Humans and the Natural Environment: The Future of Our Planet

OUR FRAGILE PLANET HUMANS AND THE NATURAL ENVIRONMENT The Future of Our Planet OUR FRAGILE PLANET atmosphere Biospher...

Author: Dana Desonie

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OUR FRAGILE PLANET HUMANS AND THE NATURAL ENVIRONMENT The Future of Our Planet

OUR FRAGILE PLANET atmosphere Biosphere Climate Geosphere humans and the natural environment hydrosphere oceans Polar regions

OUR FRAGILE PLANET

HUMANS AND THE NATURAL ENVIRONMENT The Future of Our Planet

DANA DESONIE , PH .D.

Humans and the Natural Environment Copyright © 2008 by Dana Desonie, Ph.D. All rights reserved. No part of this book may be reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying, recording, or by any information storage or retrieval systems, without permission in writing from the publisher. For information contact: Chelsea House An imprint of Infobase Publishing 132 West 31st Street New York NY 10001 Library of Congress Cataloging-in-Publication Data Desonie, Dana. Humans and the natural environment / Dana Desonie. p. cm. — (Our fragile planet) Includes bibliographical references and index. ISBN 978-0-8160-6220-1 (hardcover) 1. Environmental degradation—Prevention—Juvenile literature. 2. Nature—Effect of human beings on—Juvenile literature. 3. Human ecology—Juvenile literature. 4. Population—Juvenile literature. I. Title. II. Series. GE140.5.D47 2008 304.2—dc22 2007040403 Chelsea House books are available at special discounts when purchased in bulk quantities for businesses, associations, institutions, or sales promotions. Please call our Special Sales Department in New York at (212) 967-8800 or (800) 322-8755. You can find Chelsea House on the World Wide Web at http://www.chelseahouse.com Text design by Annie O’Donnell Cover design by Ben Peterson Printed in the United States of America Bang NMSG 10 9 8 7 6 5 4 3 2 1 This book is printed on acid-free paper. All links and Web addresses were checked and verified to be correct at the time of publication. Because of the dynamic nature of the Web, some addresses and links may have changed since publication and may no longer be valid. Cover photograph: © polartern / Shutterstock.com

Contents

Preface

vii

Acknowledgments

ix

Introduction

x

 Part oNe

Human Population and resource use 1. Population: Past, Present, and Future

1 3

2. Overpopulation

16

3. How Resources Are Used

27

 Part tWo

Water resources

41

4. Use of Water Resources

43

5. Problems with Water Use

52

6. Sustainable Water Use

64

 Part tHree

energy resources

75

7. Energy from Fossil Fuels

77

8. Problems with Fossil Fuel Use

84

9. The Energy Future

100

 Part four

Living Resources

111

10. Growing Food

113

11. Environmental Costs of Modern Agriculture

121

12. Food for the Future

132

13. Exploiting Animals for Food

143

14. Forests and Deforestation

155

 Part five

Overpopuation Revisited

15. Are There Too Many People?

165 167

Conclusion

180

Glossary

185

Further Reading

199

Index

204

Preface

T

he planet is a marvelous place with its blue skies, wild storms, deep lakes, and rich and diverse ecosystems. The tides ebb and flow, baby animals are born in the spring, and tropical rain forests harbor an astonishing array of life. The Earth sustains living things and provides humans with the resources they need to maintain a bountiful way of life. These resources include water, soil, and nutrients to grow food, and the mineral and energy resources to build and fuel modern society, among many other things. The physical and biological sciences provide an understanding of the whys and hows of these phenomena and processes— why the sky is blue and how metals form, for example— and insights into how the many parts of the planet are interrelated. Climate is a good example. Among the many factors that influence the Earth’s climate are the circulation patterns of the atmosphere and the oceans, the abundance of plant life, the quantity of various gases in the atmosphere, and even the size and shapes of the continents. Clearly, to understand climate it is necessary to have a basic understanding of several scientific fields and to be aware of how these fields are interconnected. As Earth scientists like to say, the only thing constant with our planet is change. From the ball of dust and rocks that came together 4.6 billion years ago to the lively and diverse globe that orbits the Sun today, very little about the Earth has remained the same for long. Yet, while change is a fundamental, people have altered the environment in ways unlike any other species that has ever existed before. Reminders of our presence can be found everywhere. A look to the skies might show a sooty cloud rising from a factory or a jet contrail left behind by vii

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humans and the natural environment

an aircraft. A look to the sea might reveal plastic refuse, oil, or only a few fish swimming where they once swam in countless numbers. The land has been deforested and strip-mined, while rivers and lakes have been polluted. Changing conditions and habitats have caused some plants and animals to expand their populations while others have become extinct. Even the climate—which for millennia was thought to be beyond human influence—has been shifting due to alterations in the makeup of atmospheric gases brought about by human activities. The planet is changing fast and people are the primary cause. Our Fragile Planet is a set of eight books that celebrate the wonders of the world by highlighting the scientific processes behind them. The books also look at the science underlying the tremendous influence humans are having on the environment. The set is divided into volumes based on the large domains in which humans have had an impact: Atmosphere, Climate, Hydrosphere, Oceans, Geosphere, Biosphere, and Polar Regions. This volume, Humans and the Natural Environment, describes the impact of human activity on the planet and explores ways in which we can live more sustainably. At the core of the set is the belief that to mitigate the impacts of human civilization on the Earth, each of us must understand the scientific processes that operate in the natural world; we must understand how human activities disrupt those processes and use that knowledge to predict how changes in one system will affect other systems, even seemingly unrelated ones. This series is based on the belief that science is the solid ground from which we can reach agreement on the behavioral changes that we must adopt—both as individuals and as a society—to solve the problems caused by the impact of humans on our fragile planet.

Acknowledgments

I

would like to thank, above all, the scientists who have dedicated their lives to the study of the Earth, especially those engaged in the important work of understanding how human activities are impacting the planet. Many thanks to the staff of Facts On File and Chelsea House for their guidance and editing expertise: Frank Darmstadt, Executive Editor; Brian Belval, Senior Editor; and Leigh Ann Cobb, independent developmental editor. Dr. Tobi Zausner located the color images that illustrate our planet’s incredible beauty and the harsh reality of the effects human activities are having on it. Thanks also to my agent, Jodie Rhodes, who got me involved in this project. Family and friends were a great source of support and encouragement as I wrote these books. Special thanks to the May ’97 Moms, who provided the virtual water cooler that kept me sane during long days of writing. Cathy Propper was always enthusiastic as I was writing the books, and even more so when they were completed. My mother, Irene Desonie, took great care of me as I wrote for much of June 2006. Mostly importantly, my husband, Miles Orchinik, kept things moving at home when I needed extra writing time and provided love, support, and encouragement when I needed that, too. This book is dedicated to our children, Reed and Maya, who were always loving, and usually patient. I hope these books do a small bit to help people understand how their actions impact the future for all children.

ix

Introduction

F

or the entire history of life on Earth, species have been living by certain natural rules. A species produces more offspring than the environment can support. If conditions are favorable, more of those additional offspring survive, which allows the population to grow. Whenever the population gets too high, individuals move into neighboring locations or else stay and compete for resources. As with any competition, there are some winners and some losers, so in time the population numbers may fall. Humans (Homo sapiens), a relatively new species on the planet, have found a way to expand their numbers well beyond those dictated by natural laws. By using their brains and hands, humans have blown through the natural limits in population that all other species for all of the history of life have been forced to adhere to. The numbers are astonishing: The human population was about 5 million in 8000 B.C., 300 million in A.D. 1, 1 billion in 1802, 3 billion in 1961, and 6.6 billion in 2007. This population explosion has come about because humans learned to manipulate their environment to suit their needs. Over millennia, a bird species might evolve the strategy of placing a stick in its bill to better gather ants from an anthill, but the innovation goes no further. But humans have created innovations that are utterly unprecedented in their magnitude and unfathomable in their timeframe. Modern society alters natural landscapes to grow food or build cities, engineers dams and aqueducts to move water, designs machines that run on solar energy that had been stored in the ground for millions of years (known as fossil fuels), builds ships to fish the high seas x

Introduction

and transport goods, genetically engineers crop plants to produce more yield, and creates countless other advances. Each development, particularly those that have increased food production, has gone hand-in-hand with large jumps in population. The flip side is that as population has grown, more advances have been needed to deal with these increasing numbers. So far, the connection between population increases and technological advances has kept pretty well in step. There have been temporary drops in local or regional populations—from diseases, wars, or famine—and far too many people on the planet currently live in poverty, but in general, global population has been steadily climbing for millennia and the standards of living of at least some of the planet’s inhabitants have been steadily rising. Indeed, about one-fifth of the world’s current population leads lives of great comfort: with adequate or even excess food, clean water, and material wealth that was not dreamed of even a few generations ago. Understandably, the other fourfifths of people desire lives that more closely resemble those of the wealthy one-fifth. In some developing nations, the standard of living is rising dramatically: People are eating more diverse diets, homes are outfitted with electricity and plumbing, and bicycles are being traded in for cars. Vast numbers of people, primarily in China, India, and Southeast Asia, are rapidly improving their standards of living even as their populations climb ever higher. Society, however, is now at a crossroads, or as some say, a bottleneck. The development of the technologies that have allowed the human population to grow so tremendously have spent down the natural capital: The best farmland already has been, or is currently being, farmed and some of these activities have degraded much of the land; fresh water is scarce and increasingly polluted; fish are being overharvested; forests are being briskly felled; fossil fuels are becoming depleted; and the list goes on. While the environment continues to degrade quickly, the amount of resources that people can take and the amount of pollution that they can add may be coming close to reaching the limit. The planet is already strained by the number of people and the amount of resources that the wealthy consume—and more people

xi

xii


are on their way. Few experts think that the human population will continue its exponential growth indefinitely: The rate of population increase is declining and many people think that human numbers will stabilize at between 9 billion and 10 billion in the middle of this century. That number still represents an increase of at least 2.5 billion people over current population figures, more than the total number living on the planet in 1950. Most of these additional people will be in the poor and developing nations, many of them in urban slums. The problems of the future will come from two directions: rapid population growth and the greater consumption of resources as the people of the developing nations improve their lifestyles and the people in the wealthy nations try to maintain or even improve theirs. These two factors can result in severe environmental damage, including air pollution, and limited access to basic sanitation, safe drinking water, and an adequate and safe food supply. Population growth also fuels the rate of urbanization, often leading to slum settlements and shanty towns. Some resources limit human population. Water is as important as food since people need it for drinking, bathing, and to grow food. Without clean water to drink, people sicken and sometimes die. Energy is essential to modern life, and most of the energy that people use today comes from fossil fuels. These fuels are being spent down, but perhaps more importantly are responsible for a tremendous amount of air and water pollution. Gases emitted by fossil fuels warm the atmosphere and are largely responsible for the rising temperatures the planet is now experiencing, a phenomenon known as global warming. These days, food is a limiting factor only to populations in poor countries where there is barely enough to get by, but wealthier nations may be affected as the true costs of modern agriculture need to be paid. Forests are limiting, as the people of Easter Island discovered when they deforested their island to where they could no longer sustain their way of life. Finally, the enormous human population is taking its toll on ecosystems, including forests and ocean fisheries, and thousands of species have gone extinct or are at the risk of extinction.

Introduction

Many scientists suggest that a business-as-usual course cannot be maintained and that society must make a thoughtful switch to more environmentally sound ways of living and greener technologies. The field of sustainable development seeks ways to improve the circumstances of those alive today while preserving resources and protecting the environment. Sustainability is the new buzzword, but making advances in sustainable living is both necessary and difficult. This volume of Our Fragile Planet explores some of the problems that arise due to overpopulation and over-consumption. It looks at those resources that can limit human population: water, energy, food, forests, and fisheries. Part One describes the human population, how it has risen over the past millennia, and how it typically uses resources. Parts Two through Four focus on types of resources—water, energy, and living. Each resource type is featured in a chapter that describes how it is currently being used; the consequences that arise from its use, such as pollution; and how that resource might be used sustainably. Part Five discusses overpopulation and looks to the future. Much of this discussion is speculative, since no one really knows for sure what the impact of the upcoming enormous and rapid population growth will be on human society or on the ecosystems that the planet supports.

xiii

PART ONE

HUMAN POPULATION AND RESOURCE USE

1 Population: Past, Present, and Future

t

he number of people living on Earth has exploded in recent decades. For example, a girl born in the United States in 1956 when the world’s population was 2.8 billion has lived through an increase of 135% to 6.6 billion by her 50th birthday. If she reaches the life expectancy of 80 years for an American woman, she will see the population more than triple over her lifetime to around 8.6 billion. This magnitude of population increase, both in percentages and in raw numbers, is unprecedented for any large organism over the entire his tory of the planet, except perhaps under extreme circumstances, such as after an enormous extinction event.

counting PeoPle Population is a number of the individuals of a species (a group of organisms that can interbreed) of an organism that lives in a defined area. The area can encompass the entire planet or any smaller location—either natural, like a pond, or political, like a nation. 3


World population in the century between 1950 and 2050 is expected to more than triple. While the growth rate has been declining since the early 1960s, the population is still rising rapidly.

Human population numbers are very difficult to determine. No one knows exactly how many people live in any country, not even a wealthy, technologically advanced nation like the United States. People can be born and die without leaving records; many people may arrive or leave illegally or without official notice. Population numbers for a nation or the world are only the best guesses available. Population growth rate is a measure of the change in popula tion over a period of time. There are two types: Natural growth rate is the amount the population is growing based on births and deaths. When the birthrate (the number of births per 1,000) exceeds the death rate (the number of deaths per 1,000), the population

Population: Past, Present, and Future

increases. When the death rate exceeds the birthrate, the population shrinks. Total growth rate also accounts for the people who move into (immigration) or out of (emigration) the area. The global pop ulation growth rate has been decreasing in recent decades. At its peak, from 1963 to 1964, the global growth rate was 2.2%. As of 2007, the growth rate had dropped to an estimated 1.17%. The age structure of a population affects growth rates. If the popu lation has an enormous number of young people relative to the number of older people, the population will grow at a higher rate since the young people are yet to have children. If the number of young people

World population growth rate peaked in the early 1960s at more than 2 percent per year, due primarily to a decrease in the death rate, and has been declining since. The population growth rate is expected to continue to decrease in the coming decades. The large dip in 1959 and 1960 was due to the policies of Mao Zedong’s China’s Great Leap Forward, which resulted in a massive famine.


is similar to the number of old people, children born will simply replace the older people who die and the population will not change much. Fertility rate (somewhat different from birthrate) refers to the total number of births per 1,000 women of reproductive age (which is considered 15 to 44 years). The world average fertility rate in 1990 was 3.3 per 1,000, but by the year 2002, it had declined to 2.6, where it remains. Fertility rates vary enormously by country: In 2007, it ranged from 7.38 children per woman in Mali to 0.98 children per woman in Hong Kong (part of the People’s Republic of China). A nation’s replacement fertility rate is the number of births needed to replace the parents. Although this number would seem to be two births per couple (one child to replace each parent), the replacement fertility rate must actually be higher, because some children die before reaching reproductive age and some women do not have children. How much higher the rate must be varies greatly by country. In industrial nations, where fewer children die, the replacement rate is about 2.1 per couple. In poor nations, where many children do not survive to adulthood, the replacement rate may be 3.35, as it is in the African nation Swaziland. In the United States, the fertility rate is not much higher than the replacement fertility rate. The natural growth rate is about 0.6%. Immigration raises the nation’s total growth rate to 0.9%. Canada has even more of a discrepancy, with a 0.3% natural growth rate and a 0.9% total growth rate. But even small growth rates add up over time. The population in the United States passed 300 million in 2006 and is projected to hit 400 million in 2043, just 37 years later. Some European nations have negative growth rates, usually because they have very low fertility rates. Often, these nations try to attract im migrants to help support their economies. For example, Germany’s natural growth rate is -0.2%, but its total growth rate is 0.0%. If immigration continues to prop up falling birthrates, Germany’s popu lation will remain stable. This is not the case for the Czech Republic: With a total growth rate of -0.1%, due to low fertility rate (1.2 chil dren) and high emigration (about 1 per 1,000 residents annually), the


population is shrinking. Most poor nations have high growth rates due to their high birthrates: Afghanistan’s birthrate, for example, is 4.6%, but is currently decreasing. Environmental and cultural factors both play a role in population growth rates. Birthrates go down as women become educated and join the work force, which explains the lower birthrates of the developed nations. The availability of family planning and medical abortions in developed nations allows couples to plan how many children they want to have. Population growth in developed nations is generally due to people living longer and to immigration, as people move from poor or developing nations, where life is difficult, to developed nations, where conditions are more favorable. Birthrates are highest in poor nations where women have few opportunities. Birthrates in developing nations are also high but are declining as women become educated and join the workforce. Death rates are higher in developing and poor nations compared to developed nations due to higher infant mortality (the number of children who die before the age of one) and child mortality (the number of chil dren who die before the age of five), in addition to higher incidences of fatal disease, starvation, and war. In many developing nations, death rates are declining as the clean water and basic sanitation decreases child mortality and health care becomes more widely available. Population density is the number of people inhabiting a given area. Global population density is about 115 people per square mile (44 per square kilometer), but since much of the Earth’s land is uninhabitable, the population density is actually much higher. Popu lation density varies greatly within and between nations. The highest population density in the world, approximately 44,000 per square mile (16,923 per sq. km), is in the tiny nation of Monaco, which, at only 0.75 square miles (1.95 sq. km) is home to about 33,000 people. Hong Kong and Singapore each have more than 15,000 per square mile (6,000 per sq. km). Greenland, which is mostly uninhabitable ice cap, has a population density of about 0.067 per square mile (0.026 per sq. km). In the United States, where the overall population (continues on page 11)

8


Population Demographics Professor Joel E. Cohen of Rockefeller University studies population trends, past and recent. His recent papers in Science (November 2003) and Scientific American (September 2005) provide a wealth of information on population and demographics (which refers to characteristics of population groups based on age, gender, income level, or other factors). Some of the population trends presented by Cohen are as follows: For the past 1,500 years, the rate of population growth has been faster than exponential (in exponential growth, the growth is directly proportional to the quantity itself, meaning that the larger the quantity gets the faster it grows).  Population more than doubled in the 45 years between 1960 (3 billion) and 2005 (6.5 billion). No person who died before 1930 had lived through a doubling of human population. No one born in 2050 or later is likely to live through a doubling of human population.  The peak world population growth rate was in the 1960s, 

• •

when it was more than 2% per year.  Beginning in 1990, 86 million people were added to world population annually.  In 2006, the growth rate was 1.14% per year; an annual increase in global population of 74 million to 76 million.  In 1960, only five countries had fertility rates at or below replacement; by 2000, the number had jumped to 64 countries. These nations, in which the population losses are no longer being replaced by births, contain 44% of all people. Cohen has also identified the ways in which demographics are shifting: 

Nearly all the population growth is taking place in the world’s poorest countries: The fertility rate of women in poor countries is 2.9 versus 1.6 in wealthy countries. Half of the population increase predicted by 2050 will be in nine countries. The only rich country on the list is the United States,

• •


On a graph of human population from 10,000 b.c., when people were hunter-gatherers, until the turn of the 21st century, the greater-than-exponential population growth of the past few centuries, and especially the past century, is extremely clear.

where immigration accounts for one-third of population growth.  Global population is aging, due to reduced fertility and improved survival: In 1955, 14.5% of people were age 14 and younger;

•

in 2005, that number was 9.5%. In 1960, 81% of people were age 60 and older; in 2005, that number was 10.4%. The average lifespan at the beginning of the twentieth

• •

(continues)

10


Satellite images showing population growth as indicated by urbanization in Jakarta, Indonesia, from 1976 (6 million), 1989 (9 million) and 2004 (13 million). Vegetation appears red and urban areas appear light green. (NASA/GSFC/METI/ERSDAC/JAROS, and U.S./Japan ASTER Science Team)

(continued)

century was about 30 years; at the beginning of the twenty-first century, the average lifespan was about 65. Still, half of the people in the world are under the age of 25: In the least developed countries, half the population is 23 and younger.  Populations are shifting from rural to urban areas, a phenomenon known as urbanization. The shift has spread from developed nations to developing nations. In 1800, about 18 million people (2%) lived in cities.

•

•

• In 1900, about 200 million

people (12%) lived in cities. New York was the first city to reach a population of 10 million, around 1950. In 2000, about 47% of all people lived in cities and 10% of those lived in cities of 10 million people or more. Fourteen times more people lived in cities in 2000 than in 1900, a rise to 2.9 billion. In 2000, 19 cities had 10 million or more people: Only four of these cities were in developed nations. In 2007, for the first time, there are more people living in cities than in rural areas.

•

•

Population: Past, Present, and Future (continued from page 7)

density is 85.1 inhabitants per square mile (32.9 per sq. km), the borough of Manhattan in New York City has the highest population density of approximately 70,190 per square mile (27,099 per sq. km). By contrast, the population density of Alaska is about 1.17 persons per square mile (0.45 per sq. km).

Past Population Trends Determining past population is even more difficult than estimating current population because many communities did not keep records. Researchers extrapolate the data from locations where accurate rec ords were kept or from modern records. These estimates, of course, are very rough. For millennia, human population grew steadily, but at a fairly slow rate. Between the mid-eighteenth and the mid-twentieth centuries, the most rapid population growth took place in the developed world, primarily Europe and North America. This rapid growth was driven by advances in agriculture and the birth of industry, which allowed people to move off farms and into cities for jobs. During this period, population growth outside the developed world was relatively slow. Around 1950, less developed countries had twice the population of developed countries. Around this time, however, rapid population growth shifted from the developed to the developing world as women in developed nations gained the ability and desire to control the num ber of children they would have. Meanwhile, the developing nations grew, not by increasing their birthrates, which were already high, but by reducing their death rates. With help from developed nations, they learned to better control diseases and increase food production. As a result of these changes, the relative populations in developed and developing nations have changed and will continue to change: By 2050, six times as many people will live in the less developed world than live in the developed world. Periodically, an area will experience a large drop in population due to disease, war, or famine, although the population will tend to recover rapidly. A disease that attacks many individuals in a

11

12


population is called an epidemic; when it affects a large part of the world it is called a pandemic. In fourteenth century Europe, Asia, and the Middle East, the bubonic plague pandemic, known as the Black Death, killed an estimated 75 million people, or between onethird and two-thirds of the region’s population. More than 60 million people died during World War II between 1939 and 1945, so far the deadliest war in human history. During the Irish Potato Famine of 1845 to 1849, between 500,000 and 1 million people starved to death in Ireland, about one person out of six. In addition to the deaths by starvation, about 2 million Irish moved to Great Britain, the United States, Australia, and other nations. Population also declines when environmental conditions become difficult. The Norse settlers farmed in Greenland beginning around a.d. 1000 when the climate was atypically warm, but died out in the early fourteenth century when the Little Ice Age cooled the climate and prevented them from maintain ing their way of life.

Population Projections The phenomenal population growth rates of the nineteenth and twenti eth centuries are continuing into the twenty-first century. The addition to the world’s population of 75 million people a year is like adding nine cities the size of New York City or six cities the size of the world’s most populous city, Mumbai (Bombay), India. Following the trend of the past 50 years, nearly all of these people will be added to the less developed and poor nations. The amount of time it takes for a population to double is known as the doubling time. Since growth rates change over time, the dou bling time changes also. “The Rule of 70” is a useful way to measure a quantity growing exponentially at a constant rate: By this rule, a 1% growth rate leads to a doubling of the quantity every 70 years; a 2% growth rate leads to a doubling every 35 years. When the world’s population growth rate was at its peak of 2.2%, the doubling time was only 33 years. In 2006, with a growth rate of 1.14%, the doubling time has grown to 61 years. The doubling time of individual nations varies


The Number of Years between the Addition of One Billion People to Earth’s Population Human population

Year reached

Number of years it took

1 billion

1802

All of human history

2 billion

1927

125

3 billion

1961

34

4 billion

1974

13

5 billion

1987

13

6 billion

1999

12

7 billion

2012 (predicted)

13 (predicted)

Source: Joel E. Cohen, Science (November 2003) and Scientific American (September 2005).

as well: Afghanistan’s doubling time is 14.5 years, whereas Canada’s is 77.7 years. The number of years it takes to add one billion people to the planet has decreased greatly in the past two centuries, as can be seen in the above table. Since the global population growth rate is now declining, the projected number of years it will take to reach 8 billion is 16 years: It will take 26 years to reach 9 billion. Predicting future populations is the most difficult task of all, more difficult than determining present or past population. Events that cause populations to decline are factored in if they have occurred in the recent past. For example, since famines periodically strike sub-Saharan Africa, population projections include the loss of some Africans to starvation. Events that are possible but have not yet taken any lives, such as thermonuclear war or severe climate change, are not included in population projections. Since no one can predict when a pandemic like the bubonic plague or a disease no one has yet heard

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of may arise, these factors are also not taken into account. If a pan demic occurred, it could create a huge discrepancy between real and projected population. Population growth is altered by more-normal occurrences, such as the education and employment of women. At the State of the Planet 06: Is Sustainable Development Feasible? conference held in New York in March 2006, Joel E. Cohen showed how sensitive population projections are. “If women have half a child more than anticipated in this continuing fall of fertility, we’ll go to one and a half billion more [people]. If women have half a child less, we’ll go to almost one and a half billion less [people]. In other words, a one child difference in behavior per woman means a three billion people difference by 2050.” Death rates decrease with improved sanitation, health care, and medi cal technology. Because there are so many unknown factors at work, organizations such as the United Nations Population Fund (UNPF) model differ ent scenarios for the future. If growth rates remain constant, global population will reach 13 billion in 2067 and 26 billion in 2128. Most researchers think that the population growth rate will continue to decline—due to the declining birthrates and increase in death rates, particularly due to the AIDS pandemic—and that the population will stabilize at around 9 to 10 billion in the middle of the twenty-first century. Cohen also uses demographic trends to create a picture of the future: 

Rapid growth of population will continue for a period of time, since about one-third of the world’s population is under the age of 20.  Many developed countries will continue to lower birthrates and will increase population only by immigration.  Nearly all of the population growth will be in cities: About 2.1 billion people will be added to cities in poor countries by 2030 (over 2000 population numbers), a rise from 40% to 56%.

•


• According to Cohen, “In effect, poor countries will have

to build the equivalent of a city of more than one million people each week for the next 45 years.” Wealthy countries will continue to urbanize, from 75% of their population in 2000 to 83% in 2030.  Fertility rates are currently about 2.9 in poor countries ver sus 1.6 in wealthy countries. By 2050, the rates will drop to 2.0 in poor countries and rise to 1.9 in wealthy countries.  In poor countries, the fraction of people under 15 years of age is 33%; in wealthy countries, it is 18%. By 2050, these numbers will be 21% and 16%, respectively.  Global life expectancy will increase from 65 years in 2000 to 74 years in 2045. In wealthy countries, the rise will be from 76 years to 82 years. In poor countries, life expectancy will rise from 63 to 73 years.

•

Wrap-up The decline in population growth rates is reducing the rate at which population is growing. But population is still growing phenomenally, with an additional 75 million people arriving on the planet each year. The projected increase in population between 2005 (6.5 billion) and 2050 (9.1 billion) is greater than the total population of the world in 1950 (2.5 billion). The growth will largely take place in poor and developing nations, particularly in urban slums.

15

2 Overpopulation

e

arth’s human population is incredibly high and climbing. For centuries, some experts have thought that population growth would overtake food production, and disastrous consequences would result. So far, though, nothing dire has happened on a global scale. As will be covered in this chapter, the response of nations to population growth differs: Some countries encourage their people to have more children, while some nations encourage them to have less. The population of some areas is reduced by external forces, such as the AIDS pandemic in Africa.

carrYing caPacitY and overPoPulation The carrying capacity of the population of a species in a given location depends on how many of the organisms that environment can support without depleting its resources. Carrying capacity is affected by the availability of space, food, water, and many other factors. When birth and death rates are equal, the land is at its carrying capacity for 1

Overpopulation

the present set of conditions. If conditions change favorably, the organ ism’s population increases, as does the land’s carrying capacity for that species. If conditions return to normal, the organism’s population will drop, sometimes dramatically. For example, if good weather allows a food plant to expand in an area, that area’s deer population may explode. The population will return to normal, or fall even lower, when the amount of available food drops, or when an increased number of predators (animals that eat other animals for food), takes advantage of the increase in their prey (the animals eaten by the predators). When a species exceeds a region’s carrying capacity, overpopulation occurs. A region is overpopulated if it cannot provide for that species without either becoming depleted in resources or experiencing environmental damage, or both. There is no absolute population num ber or population density that means that a region is overpopulated. An overpopulated species may expand its range, if there is room; if there is nowhere for the species to move, its population will decline. With our large brains, erect postures, and opposable thumbs, humans have been able to enormously increase the planet’s carrying capacity for our own species. People can alter their environment to better meet their needs: One way is by growing crops rather than just gathering food from the natural environment, as all other animals do. People also do not need to rely on a single region to meet all of their needs: They can trade for resources with people nearby or half a world away. Humans are also ingenious: If a resource is depleted, they can find other ways to obtain it, or they can substitute a different resource. For example, if water is in short supply, but energy is abundant and cheap, humans can create drinking water by building plants to desali nate seawater. Humans undoubtedly exceed the carrying capacity of some regions—sub-Saharan Africa, a region of chronic hunger and overpopulation, is one example.

Overpopulation Debate Debate about overpopulation likely began with an essay written by the Reverend Thomas Malthus (1766–1834) and published in 1798 (when

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world population was 978 million). In “An Essay on the Principle of Population,” Malthus argued that population grows geometrically—the ratio of two successive numbers is a constant (as in 2, 4, 8, 16, 32, 64, 128, and so on)—but food availability grows arithmetically—the difference between two successive numbers is a constant (as in 1, 2, 3,

Types of Resources Economists recognize three broad categories of resources: natural resources, human resources, and capital. natural resources are the raw materials used to produce goods. They are found in nature and used with little modification. Land and soil, minerals, fossil fuels, forests, and fish and game animals are natural resources. Hu- man resources refer to labor, the work that people do to produce goods. capital refers to the human-made tools and machines people use to produce goods. Unless otherwise noted, the word resources in this discussion will refer to natural resources. Food is not a natural resource because agriculture requires the use of human resources, through labor, in addition to the use of natural resources, such as land and soil. Natural resources may be renewable or nonrenewable, although renewable resources may be used nonrenewably. nonrenewable resources are those that natural processes do not replace on human timescales. All fossil fuels are nonrenewable since they take millions of years to form. Fossil fuels are ancient plants that

Earth processes have transformed into oil, gas, or coal. Since fossil fuels were once plants, the energy they contain is ancient solar energy. renewable resources are those that are replaced by natural processes on a human timescale. Supplies of renewable resources will never run out, provided they are used carefully. Renewable resources can be nonliving or living. Solar energy, a nonliving resource, strikes the planet each day and is virtually limitless. Trees are a living and renewable resource because they can be grown on human timescales. Renewable resources can be used sustainably. sustainability refers to resource use that “meets the needs of the present generation without compromising the ability of future generations to meet their own needs,” according to the 1987 Brundtland Report, by the United Nations World Commission on Environment and Development (WCED), which was written to address the consequences of the deterioration of the human environment and natural resources.

Overpopulation

4, 5, 6, 7, 8, and so on). Simply put, Malthus predicted that population would eventually grow to outstrip food supply. Malthus recognized that people were continually making technologi cal advances to produce more food, but he thought that ultimately food production would not be able to keep up with population growth. The result would be a dramatic drop in population by war, epidemic (pesti lence), or famine, sometimes called the Malthusian catastrophes. Mal thus said that people could avert these disasters by lowering population by choice (through sexual abstinence and late marriage, for example). While world population has grown nearly seven-fold since Malthus’ prediction, no global catastrophe has taken place, as of yet. Malthus had made several mistakes in his analysis. Most importantly, he underestimated the growth of agricultural productivity, which has been greater than he could ever have imagined. Even very recently, between 1995 and 2004, United States Department of Agriculture (USDA) sta tistics showed an increase in corn yield of 41%, with similar increases for wheat. Malthus also did not recognize that the population growth rate would eventually decline, although this has occurred only very recently. Paul R. Ehrlich’s The Population Bomb (1968) was written in a similar vein to Malthus’ essay. Ehrlich developed “scenarios” in which he predicted that population growth would overtake resources, with massive famines causing the deaths of hundreds of millions of people. Ehrlich’s book came out just before the beginning of the Green Revolution (to be discussed in Chapter 10), which brought about an astronomical increase in food production. He also did not realize that the fertility rate would drop in the developed world. In 1972, the Club of Rome, a group dedicated to the improvement of human societies, published The Limits of Growth. Led by environ mental scientist Donatella Meadows, the book presented the results of a computer model that calculated that people were using Earth’s resources at a far faster rate than they were being replenished. Mead ows and her colleagues concluded that some natural resources would run out by the end of the twentieth century and that serious ecological

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problems would arise in the 2030s and 2040s. In 2004, a new edition of the book using more extensive computer models suggested that these consequences will be realized within the lifetimes of some people who are alive today. In 1994, 58 academies of science worldwide said that the human population could not be sustained in the long run. None of these predictions have yet come to pass, but there are rea sons to think that the human population now exceeds Earth’s carrying capacity: Many of the world’s people live in poverty, without enough food or access to safe drinking water. Many resources are being used unsustainably. In addition, providing for the human population gener ates an enormous amount of waste and pollution. Optimists say that population changes are going in the right direc tion: According to the United Nations, the population growth rate is decreasing and the percentage of people who live in abject poverty (on less than $1 per day) is declining, from 27.9% of the developing world in 1990 to 19.4% in 2002. (Most of the decline took place in Asia. Unfortunately, sub-Saharan Africa had an increase in this group of 140 million over the same time period.) Optimists think that scientists will continue to develop new technologies, including agricultural tech niques, which will sustain a growth in global population. Biotechnol ogy and genomics are two examples of fields where enormous gains can be made.

Controlling Population A nation, region, or family that wants to control its population usually does so by reducing its birthrate. Births can be controlled by sexual abstinence, contraception, and abortion. Throughout human history, cultures have promoted or even required practices that reduced their birthrates. For many generations, the Siwans have inhabited a small oasis in the Libyan Desert in Egypt. Until recently, their population was limited by the small amount of available resources at the oasis. So that they could live sustainably, the group developed cultural practices that controlled their birthrate. For example, men were not allowed to marry before age 40. The government of the world’s most populated

Overpopulation

People on Nanjing Pedestrian Street in Shanghai, China, in May 2002. (AP Photo/Eugene Hoshiko)

nation, China, with about 1.3 billion people (2006), has used both voluntary and enforced cultural means to keep down the nation’s popu lation growth. Before the availability of modern technologies like birth control and safe abortions, some native cultures controlled population by using infanticide. The Inuit, who inhabit the extremely harsh Arctic environment, sometimes abandoned infants to the cold when times were desperate. The native people of the New Guinea highlands lived self-sustainably in their environment for 46,000 years, because they effectively limited their population by using all the techniques avail able to them, including infanticide. Modern studies have shown that the best way to reduce population growth voluntarily in the developing world is to educate and empower girls and women. Woman who are educated and have jobs, and who

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Controlling Population in China The government that exerts the most control over population growth is The People’s Republic of China (PRC). The Chinese government’s concern with birthrate began with the establishment of the PRC in 1949. Mao Zedong, the PRC’s first leader, established a bold economic policy—called the Great Leap Forward—that, among other policies, encouraged Chinese peasants to have as many children as possible. As a result, in 1960, a Chinese woman bore an average of six children, resulting in exponential population growth and a massive famine. During the 1970s, a voluntary program encouraged people to have children late, to wait a long time between births, and to have only a few children. In 1976, Deng Xiaoping, Mao’s successor, recognized

that China’s economic development was stifled by the need to care for so many people. Deng stepped up government and social pressure with the “One is good, two is OK and three is too many” campaign. During the 1970s, fertility rates dropped from 5.9 to 2.9 children per woman. In 1979, the voluntary program was scrapped for the mandatory one-child policy, which offers incentives to families that have only one child and penalizes those that have more. While the rule is strictly applied to most urban families, there are many exceptions. Rural families, which include about 70% of Chinese, are allowed to have two children if the first is female or disabled. Boys are more desired because they are thought to be better able to help on the farm and because Chinese custom

have the capability to control how many children they have, have fewer children and are able to better care for those they have. These factors are partially responsible for the declining birthrate seen in most of the world.

PoPulation groWtH rate decrease Global population growth rates are decreasing, although population is still growing rapidly. Other factors contributing to this decrease, in addition to changes in the lives of women, are falling fertility rates (because of increased contraceptive use), and the AIDS pandemic.

Overpopulation

dictates that boys support their own elders while girls support their in-laws. In some major cities, parents who are themselves only-children are allowed to have more than one child to assist with the support of elderly relatives. Under the one-child policy, China’s fertility rate has stabilized at about 1.7 births per woman since 1995. Nonetheless, since the number of people of reproductive age is very high, China’s population is still growing. The government’s goal is to stabilize population at around 1.4 billion to 1.6 billion by 2025. Opponents of the one-child policy say that having children is a fundamental human right and that the voluntary program was reducing birthrates. They point to practices that the government is alleged to use to compel adherence to the policy, such as

bribery, coercion, forced abortions, forced sterilization, and possibly infanticide. The policy has caused some social problems: Boys and young men now outnumber girls and young women, suggesting that some couples are aborting or abandoning their female children. Proponents of the policy say that helping people rise out of poverty respects their human rights. Without the policy, China would have 300 million more people, the number of people living in the world’s third most populous country, the United States. Having fewer people is thought to have reduced problems with crowding, epidemics, slums, ecosystem abuse, pollution, and the ability of the government to provide social services. For the 1.3 billion Chinese population, this may be an advantage.

Many developed countries have reduced their population growth so much that their fertility rates are below replacement levels. These nations that do not have high immigration rates have declining populations. Population decline can lead to the economic problem of underpopulation. Nations are underpopulated when there are too few young people to support the older generation. Some nations are so concerned about the social consequences of underpopulation that they are offering financial incentives to women who have children. Singapore, with a fertility rate of 1.06, nearly the lowest in the world, offers $3,000 for the first child, $9,000 for the second, and as much as $18,000 for the third and fourth.

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The AIDS Pandemic The deadly disease known as acquired immune deficiency syndrome (AIDS) is mostly under control in the developed nations. Preventative measures that slow the transmission rate of the human im- munodeficiency virus (HIV) that causes AIDS are widespread. (These measures include sexual abstinence, condom use, and no needle sharing for intravenous drug users.) Antiviral medications keep symptoms under control for those who are infected. These advances, however, have not been seen in the Third World, where the disease has become a pandemic. The Joint United Nations Program on HIV/AIDS (UNAIDS) published a 2006 Report on the Global AIDS epidemic that contained many statistics that reflect the

state of the pandemic through 2005. Some of these statistics are as follows: 

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Worldwide, 1.0% to 1.3% of adults 15 to 49 years old, or approximately 40 million people, were infected with HIV. AIDS has killed more than 25 million people since it was identified in 1981. 2.8 million people, including more than 570,000 children, died of the disease in 2005. More than 5 million people became infected with HIV in 2005. Sub-Saharan Africa is the hardest hit region: With 10% of the world’s population, the region has 60% of the people infected with HIV/AIDS. 6.6% to 8.0% of adults are infected. More than 20 million people are infected, including 2 million children. Life expectancy in the 35 African nations most affected has been reduced on average by 6.5 years but far more in the hardest hit nations.

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An African woman with AIDS and her daughter on her hospital bed. (Sean Sprague/The Image Works)

Overpopulation

• In Swaziland and Botswana,

30% of adults carry the virus.

When adults become ill or die, there is the loss of human capital: The victims are not able to work, leaving their

f amilies without support and their nations without skilled workers. In countries with lowered life expectancy, the gross national product (GNP), a measure of a nation’s economic output, is also lower. Families often use their (continues)

Life expectancy dropped precipitously after these African nations were hit by HIV/AIDS. In Botswana, life expectancy dropped more than 20 years in a little more than a decade. Data from World Bank, World Development Indicators, 2004.

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(continued)

meager resources to care for the sick adults rather than sending the children to school or otherwise developing their economic security. The loss of workers means the loss of taxes for the government, reducing the money available for health care and education. As infected women die, children are left orphaned—

i n 2005, there were about 12 million AIDS orphans. Predictions for the future of AIDS in sub-Saharan Africa vary, even within the same organization. UNAIDS foresees a range of possibilities from a stabilization and decline in deaths around 2012 to continued growth in cases, so that by 2025, 90 million people may be infected.

Wrap-up Malthus, Ehrlich, and other population doomsayers have been wrong, at least so far. While Malthus would undoubtedly find the current global population staggering, his predicted consequences of such a large human population have not come to pass. Neither have Ehrlich’s, whose book was published just before the advent of the Green Revo lution in agriculture. Overpopulation is sometimes ignored as an environmental problem. However, many people think that humans are exceeding the planet’s carrying capacity because of how they use resources unsustainably and degrade the environment. Some say that overpopulation is the premier environmental problem and that having too many people will soon become a crisis, if it is not one already.

3 How Resources Are Used

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lobal resources are used at extremely unequal rates around the world. For example, people in developed nations use 32 times the resources of those in the rest of the world. Overconsumption (the unsustainable use of resources), along with over population, places a strain on the planet’s ability to provide these resources and to absorb the waste that their use generates, as will be discussed in this chapter. New strategies for resource use are being developed to allow people in the First World (the developed nations) to maintain their standard of living, while allowing those in the Third World (the developing nations) to gain access to the materials and ser vices that will help them lead healthy and productive lives.

tHe evolution of resource use Through much of human existence, groups of people lived as hunters and gatherers: They migrated seasonally to take advantage of wild foods, plants, fruits, nuts, fish, and game. Huntergatherers used 2

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water from nearby sources like streams or lakes, and burned wood for warmth, protection, and to cook their food. Since they moved frequently, these people collected few possessions. Most huntergatherers formed trade networks with nearby groups to obtain ma terials they needed or wanted. This lifestyle is still practiced by a few isolated groups, but most hunter-gatherers have now become settled. Anthropologists now think that some hunter-gatherer groups modi fied the landscape to better suit their needs. Some groups of Native Americans, for example, preferred to hunt bison, buffalo, antelope, and deer because they provided large amounts of meat and hides for shelter and clothing. Because these large grazers forage on prairie grasses, the people who hunted them set fires to keep forests from encroaching on the prairie, and thus altered the natural landscape. In much of the Old World, and in some parts of the New World, some groups developed agriculture. As they needed more and more good farmland, farmers continued to clear forests and drain wetlands (poorly drained regions that are covered all or part of the time with freshwater or saltwater). Irrigation was necessary to grow crops in some arid and semi-arid regions, so people built canal systems to bring in water. Farming provided a year-round food supply, and so people settled into stationary communities. This allowed them to build permanent houses and collect material possessions. With a more reli able food supply and stable homes, towns grew larger and population density increased ten- to twenty-fold. Elaborate material cultures grew up around rulers and reli gious institutions. The European nations—primarily Portugal, Spain, France, and England—became so hungry for resources that they needed to look outside their homelands. From the early fifteenth cen tury, European explorers traveled the world searching for gold and silver, adding wood, food, and spices to their searches in later years. The seemingly endless forests of the New World fueled the European conversion to machine labor from human labor, a process also known as mechanization that began in the early eighteenth century.

How Resources Are Used

The turn of the twentieth century introduced high levels of industrial productivity in the United States. Children, such as this young girl in a textile factory, were often exploited for their labor. (Lewis Hine/Photo Researchers)

Around 1850, people discovered the enormous amount of energy contained in coal and the Industrial Revolution began. Farmers used the machines invented around this time to produce more food with less human labor. This led to peasants moving to cities in search of factory work. Transportation networks were established to haul food, fuel, and other materials into the cities. As towns grew larger, water was brought in by pumps and canals. Fossil fuels increased in impor tance in the late nineteenth and early twentieth century as the liquid fuel petroleum began to power automobiles and other engines. In industrial nations, wood was still used for construction but its impor tance as a fuel decreased as the importance of fossil fuels increased.

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Resource Use Today The minimum requirements for a healthy and productive human life are food, clean water, clean air, shelter, warmth, and basic medical care. A better quality of life includes education, jobs, sanitation, waste management, and transportation. The distribution of wealth worldwide is like a pyramid. There are many people on the bottom who have access to few resources. The middle is made up of people, mostly in the developing countries, who lead healthy lives, but are striving for a higher standard of living. On the top are relatively few wealthy people with high-quality lives and many material possessions. These people live mostly in the developed nations. The poorest nations are mostly in sub-Saharan or West Africa. The economic growth taking place in other nations is passing them by. Each day, about one billion Africans fight for the food, safe drink ing water, and shelter they need to survive. Most have no access to health care: Even a one-dollar drug that can save a child’s life is out of reach. Because they live so close to the edge, these people are extremely vulnerable. They are easily wiped out by drought or illness. Fortunately, the number of abjectly poor people is declin ing, but the poorest people are experiencing worsening conditions: deteriorating economics, greater hunger, shortened life expectancies, rising child mortality, spreading HIV/AIDS, and the increasing inci dence of famine. People in developing nations mostly have low standards of living, as in the poor nations. But some developing nations—China, India, and the countries of Southeast Asia among them—are experiencing tremendous economic expansions. China, for example, is an awaken ing economic giant. The country’s enormous population (over one-fifth of the world’s total) is making its mark globally by manufacturing goods cheaply. The nation’s economy has increased six-fold since 1978 and China is now the world’s fourth largest economy. China is rapidly industrializing and urbanizing and, as a result, uses one-third of the world’s steel and nearly half of the world’s concrete. To fuel its economic expansion, China uses more coal each year than the United States, the European Union, and Japan combined.


The result of this economic progress is an amazing improvement in people’s lives. China’s poverty rate has decreased from 53% in 1981 to below 10% in 2001. Life expectancy jumped from 32 years in 1950 to 73 years in 2007, and infant mortality dropped from 300 per 1,000 in the 1950s to 22 per 1,000 today. Despite the burgeoning economy, the money must be divided up among so many people that the average gross domestic product (GDP) per capita (per person) is still only one-fifth that of the United States. China also has a large wealth disparity between the coastal cities and the inland regions, but the government is working to develop the interior and bring economic prosperity. China anticipates a bright future with a projected 45% increase in GDP between 2006 and 2010. China hopes that its percapita economic output will triple between 2005 and 2020. About 1.7 billion people worldwide belong to the “consumer class,” which is characterized by the ownership of large houses and several cars, diets of processed foods, and the accumulation of nonessential consumer items like cell phones and video game consoles. A few of these people reside in the developing nations, but most live in the world’s wealthiest nations, found primarily in Europe, North America,

Rural New Jersey exhibits multiple mini-mansions such as the one pictured here. (lisas212/iStockphoto)

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This page and next: The ecological footprint of selected nations, from the nation with the largest footprint, the United Arab Emirates, to the one with the smallest footprint, Afghanistan. The red line shows the level at which the planet’s human population would be sustainable (discounting the needs of wildlife): 1.8 gha per person.

South Pacific nations (such as Australia and New Zealand), and Asian nations (such as Japan, Singapore, and South Korea). People in wealthy nations have lifestyles beyond what most anyone could imagine even only two or three generations ago. Houses are larger than they used to be: For example, the average home built in the United States increased from 1,500 square feet (140 square meters) in 1970 to 2,300 square feet (214 square m) in 2005. Larger houses take up more land, require more natural resources to build and main tain, and more energy per person to run. The number of people living in one house has decreased by an average of one because children no


longer live with their grandparents, and rising divorce rates have split one-family households into two. Houses are now better equipped: 23% of households had central air conditioning in 1978, while 87% did in 2006. People own more cars than ever before—in the United States, there are more cars than there are licensed drivers. Electronic devices that did not even exist 50 (or even 20) years ago are now considered essential. On average, each citizen of the United States, Western Europe, and Japan consumes 32 times more resources than does each citizen in the Third World. The amount of raw material coming into developed nations is astonishing. A recent analysis of Germany, the Netherlands, Japan, and the United States by the World Resources Institute (WRI) in Washington, D.C., estimates that these countries have an average per-capita material inflow of 41 to 73 tons (45 to 80 metric tons). That

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amounts to about 300 shopping bags of materials per person per week (weighing the same amount as a luxury car). Of that total, about 40% is made up of fossil fuels and fuel-combustion engines. People in these wealthy nations are well immersed in over-consumption. Just as in colonial times, the developed nations cannot sup port themselves with their own resources. Countries no longer have colonies, but multinational corporations make deals with the govern ments of developing nations to use those nations’ resources. Japan, for example, is the most forested developed nation, but the country gets its timber from the tropical forests of Southeast Asia. Because a foreign logging corporation has no long-term stake in the health of the nation’s forests, when a forest is depleted of valuable timber, the corporation leaves, often without replanting. The local people receive little financial benefit, but lose access to the forest’s resources. Min ing often takes place the same way. Because resource use around the globe is extremely varied, dif ferent people and different nations have very different impacts on the planet. Each individual person’s (or country’s) impact is described in terms of an ecological footprint, which is the amount of land that is needed to sustain that individual. To determine an ecologi cal footprint, a calculation is performed to convert the amount of energy, food, water, and other consumable materials that particular individual needs into a measure of land area, such as global hectares (gha) per capita. If human society were sustainable, each person would have an ecological footprint of about 1.8 gha. People in the United States use 9.5 gha on average, while in China, the number is 1.5 gha. Since 1950, the richest fifth of humanity has doubled its con sumption of energy, meat, timber, steel, and copper per person and quadrupled its car ownership, while the poorest fifth of humanity has increased its general consumption hardly at all. As Paul Ehrlich said in the online environmental news publication Grist in 2004, “Times have changed—population control, especially among the rich, is criti cal, but consumption control today is probably more critical and cer tainly tougher to achieve.”


Waste and Pollution Economic statistics do not fairly evaluate the impact of resource use on the planet. GDP, for example, does not include the cost of resource depletion. A nation may have a high GDP while it is logging its forests, but once those forests are gone, the country’s GDP will fall. The prices of goods and services also do not include the environmental costs. For example, the cost of a gallon of gasoline includes exploring, pumping, refining, and transporting that gas, but it does not include the costs of air or water pollution, including the human health effects. The byproduct of consumption is pollution and waste, and each citizen of the United States, Western Europe, and Japan not only con sumes 32 times more resources than does each citizen in the Third World, each of them also produces 32 times more waste. The ecologi cal footprint of a resident of the United States is 13 times that of a resident of India and 52 times that of a resident of Somalia. China’s incredible economic growth has come at a steep price. According to the Worldwatch Institute, 16 of the world’s 20 most pol luted cities in 2006 were in China. Coal is the nation’s worst problem: The low-grade coal that they mostly use pollutes the air and causes acid rain. Respiratory and heart diseases related to air pollution (the contamination of air by toxic particles and gases) are the leading causes of death. Nearly all the rivers are polluted and 90% of urban water bodies are severely polluted. Half of China does not have access to clean water. Regulations are passed to reduce pollution, but the air and water are not monitored and regulations are not enforced. Instead, the Chinese government deals with the consequences of pollution, estimating that it spends $200 billion each year on pollution-related problems. Media executive James McGregor, a longtime resident of Beijing, told Voice of America on June 28, 2006, “You can chew on the air in most cities,” he said. “The rivers are Technicolor with effluents. This place has gone through a huge economic boom and they’ve just been ignoring it.” Although they are the largest consumers, developed countries are in many ways now cleaner than they once were and cleaner than some

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developing countries. One reason is that the pollution that is created by the manufacture of consumer goods largely stays in the countries in which they are made. In addition, clean air and water legislation has forced businesses and governments in developed nations to improve air and water quality by limiting emissions and cleaning up polluted sites. Still, some pollutants are not regulated and the potential damage from others is not yet known. Environmental regulations and their enforcement are much less common in poor and developing nations. Multinational corporations are often not required to control emissions or clean their wastes as they would if they were working in their own countries. Waste from developed nations is even shipped to poor and developing countries. Enormous numbers of used electronics, known as e-waste, are finding their way to landfills where local people mine them for valuable mate rials. Seventy percent of the world’s discarded computers, televisions, and other appliances end up in China—often smuggled in. Unfor tunately, e-waste contains many toxic materials, which are released into the environment, causing pollution and illness among the local population. Wealthy countries use enormous amounts of fossil fuels, which generate air and water pollution when burned. Fossil fuels also release greenhouse gases like carbon dioxide (CO2 ) into the atmosphere. Greenhouse gases trap heat in the atmosphere, creating a temperate environment to support life. (Without greenhouse gases, nights would be frigid and days scorching, as on the atmosphere-free Moon.) Yet, while some greenhouse gases keep the planet’s temperature comfort able, additional greenhouse gases make the planet warmer, resulting in global warming. Since the end of the Industrial Revolution, global temperature has risen 1.8°F (1°C) and temperatures have jumped noticeably since the 1990s.

Sustainable Development People in poor and developing nations are exposed to images of the material wealth of the developed nations through movies, television,


p hotos, and the stories of relatives who have immigrated. Understand ably, these people want to raise their own living standards. Residents of the wealthy countries want this to happen without losing any of their own comforts. Yet, today, people are already exploiting about 20% more nonrenewable resources than can be replaced each year. If inhabit ants of the Third World lived the way people in the First World do, the impact on the planet would increase by 12 times. If only the Chinese achieved First World living standards, the impact on the planet would double. Even the use of resources in the wealthy nations is not sustain able. As Jared Diamond wrote in his 2004 book Collapse: How Societies Choose to Fall or Succeed, “. . . it would be impossible for the First World alone to maintain its present course, because it is depleting its own resources as well as those imported from the Third World.” Others have said that the world cannot support 9 billion people driving SUVs. If people in the poor and developing nations are to increase their standard of living and if people in the developed nations are to con tinue their high standards of living, it will be necessary for future development to take a different form. Sustainable development is about creating economic growth and helping people out of poverty while protecting the environment and not spending down natural resources. This calls for a change to the present unsustainable pat terns of production and consumption.

Ecosystem Services Valuable resources come from the functioning of ecosystems. An ecosystem is the interrelationships of the plants and animals of a region and the raw materials that they need to live. Ecosystems perform a number of ecosystem services that not only benefit the organisms that live within them, but also human society and the planet as a whole. Some important ecosystem services are listed as follows: 

Nearly all living creatures depend on the ability of plants and other photosynthesizing organisms to create food energy. (Photosynthesis is the process in which plants take carbon

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dioxide and water to create sugar, or food energy, and oxygen in the presence of sunlight.) Insects, birds, and bats carry pollen from one flowering plant to another: Pollination contributes to the birth of fer tile, healthy plant offspring. Bacteria perform an essential ecosystem service by break ing down plant and animal tissue and releasing the nutrients they contain so that they are available for reuse by plants and animals. Organisms make living spaces for other species. For example, a hole in a tree serves as a home for a woodpecker family. Plants keep down soil erosion—the movement of sedi ments from one location to another by water, wind, ice, or gravity—by holding soil in place with their roots. Soils contain minerals, microbes, and plant materials that cleanse the water that trickles through. Soil microbes detox ify or sequester pollutants. Living creatures undertake important interactions with the atmosphere by cycling or “fixing” atmospheric gases. Plants convert CO2 into oxygen (O2 ) and animals convert O2 back into CO2. Although nitrogen is the most abundant gas in the atmosphere, it is not in a chemical form plants can use. Bacteria and algae “fix” the nitrogen—that is, modify it chemically—so that it is in a form useful to plants. (Algae are simple photosynthesizing organisms.) Plants are an important part of the water cycle, which is the movement of water among the oceans, atmosphere, lakes, streams, and organisms. The role of plants is to take in water and to evaporate some of it into the atmosphere, a process known as evapotranspiration. Plants are extremely important for regulating global cli mate. Plants absorb CO2, keeping some excess greenhouse gases from entering the atmosphere and exacerbating global warming.


Wrap-up At the State of the Planet 06: Is Sustainable Development Feasible? conference, Jeffrey Sachs, director of the Earth Institute of Columbia University, posed a question: Could the world absorb another 2 billion or 2.5 billion people while increasing the income levels of the poor est countries using current strategies and technologies? According to Sachs, the answer is very likely no. “We can’t simply go on as is and have everyone continue the race for economic development as is with out really risking some terrible, terrible crises on the planet.” The following chapters will look more closely at the resources that limit population—primarily water, energy, and food—and at the waste their use generates. A look at how these resources can be developed and used more sustainably will also be discussed.

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PART TWO

WATER RESOURCES

4 Use of Water Resources

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he United Nations says that water is fast becoming the world’s most pressing environmental and development issue. As described in this chapter, water is needed for drinking, bathing, transportation, power, and industry, but mostly for irrigation. The availability of water affects many other issues such as food production, human health, and ecosystem health. Where water resources are limited, cooperation is necessary so that all nations and states can fulfill their needs.

Water soUrces Earth is the only planet in the solar system with abundant water, but the amount of water on the planet does not change. Water moves continually between many kinds of reservoirs: the oceans, atmosphere, lakes and streams, land and soil, and living creatures. Most of this water is seawater: Only about 2.5% of all Earth’s water is fresh, and much of that is trapped in glaciers. About 22% of the 43

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world’s freshwater—36 times more than is present at the surface—is groundwater. Water trickles down through soil and rock to enter a suitable rock layer known as an aquifer. The water table forms the top of the water layer in the aquifer through which the groundwater moves slowly. People have long gotten most of their water from surface lakes, ponds, and streams. In some developing countries, women may travel several miles a day with pots of water on their heads to meet their family’s water needs. In developed countries, water distribution is heavily engineered. Dams trap water in a reservoir, pumps move the water uphill, canals bring water to where it is needed, and pipes take it into homes and businesses. Groundwater is usually collected by use of a well, which is created when people dig or drill a hole down below the water table. In developing countries, people lower a bucket into the well and haul the water up. In developed countries, water is pumped to the surface. About 2 billion people use groundwater to meet various needs and many rural people are entirely dependent on it. In the United States, groundwater makes up 20% of the water that people use. Groundwater could be a renewable resource, but it is often not used renewably. In many places, people are using groundwater at much higher rates than it is being replenished.

Uses of Water People need clean freshwater for drinking, cooking, and bathing, but these domestic uses only account for about 8% of total water use. Globally, 70% of water use is for agriculture. About 40% of world food production is from irrigated agriculture. Industry is very water intensive, accounting for about 22% of water use globally. Power-generating plants use billions of gallons of water to cool their turbines each day. For this reason, these structures must be built near large natural bodies of water like an ocean, sea, or major river. Hydropower plants, which harness the energy of falling water, produce about 24% of the world’s electricity. To harness this energy, and

Use of Water Resources

to provide a steady year-round water source to the region’s population, nearly all of the world’s major rivers are dammed, most of them in several places. Freshwater ecosystems provide ecosystem services for people. Sur- face waters are necessary to meet the biological needs of plants and animals. Water trapped in soil is used by growing plants, whether they are wild, as in a forest, or domesticated, as on a farm. Freshwater fish are an important source of food for many of the world’s people. Fish farming, or aquaculture, in freshwater bodies is growing as a food source each year. Rivers that are allowed to flood bring nutrients onto their floodplains, providing free fertilizer for farmers. Wetland ecosystems provide enormous benefits to the environment and to human society. Wetlands are like a bank for holding water: During floods, they absorb water and reduce flood damage. Dur- ing droughts (times of below-normal rainfall) they provide water to streams. Water in wetlands seeps into the soil to recharge groundwater supplies. Many plants and animals depend on wetlands for their food and their living environment, known as habitat. Wetlands also serve as nurseries for young animals, including commercially valuable fish and shellfish species. As water trickles through wetlands, the rich soil filters pollutants. The aquatic organisms that live in wetlands also degrade toxins, so water exiting a wetland is cleaner than when it entered.

Water Use Today While water use is skyrocketing, only part of the increase is due to rising population. Much of the increased use is caused by the expansion of irrigated agriculture, changes in diets, and industrial development that have gone along with rising standards of living. During the twentieth century, water use grew six-fold, twice as much as human population. Water use from rivers and lakes doubled between 1960 and 2000. In that time, the amount of water contained by dams quadrupled. About 60% of the world’s largest 227 rivers have been strongly or

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oderately altered by dams and other engineered structures. Ground- m water use has also skyrocketed. One-quarter of the world’s water comes from groundwater—nearly 1.5 billion people rely on this water as their sole source of drinking water. People who live in wealthy countries use 10 times more water than those in poor countries. In 1900, an American household used as little as 2,600 gallons (10 cubic m) of water a year. In 2000, that number was 20 times greater, about 53,000 gallons (200 cubic m). There are many reasons for this increased water usage. At the turn of the twentieth century, only city homes had running water, while most people lived in rural areas. The amount of irrigated cropland has increased enormously, by 35% between 1970 and 2000, for example. People consume much more meat than they once did. Whereas about 800 gallons (3 cubic m) of water is needed to produce 2.2 pounds (1 kilogram) of cereal, about 4,000 gallons (15 cubic m) of water is needed to produce 2.2 pounds (1 kilogram) of grain-fed beef. The manufacture of cars, computers, and other consumer items, and the power needed to run them, all consume enormous quantities of water. The manufacture of a single car, for example, requires up to 29,000 gallons (110,000 liters) of water. Globally, humans use slightly more than 10% of renewable water supplies. While 90% of water goes unused, this water is not evenly distributed. Two-thirds of the world’s population lives in areas receiving only one-quarter of the world’s annual rainfall. North America has the most freshwater per capita. About 20% of the global average falls as rain on the Amazon Basin of South America, which is home to fewer than 10 million people. The Congo River and its tributaries receive about 30% of the water that falls on the African continent, but only 10% of Africa’s population lives there. However, this water is not lost: It sustains the tropical rain forests that depend on it. Still, it is also not available to the human populations that need it. China has only onequarter the water resources per capita that the rest of the world has. At this time, more than 40 countries cannot meet the daily water needs of their populations. They either do not have enough water, they do not have the infrastructure to transport the water to the people who


need it, or they do not have the ability to clean the water once it has been contaminated. About 1.2 billion people worldwide do not have enough clean water for drinking and washing each day. Groundwater is being mined (used unsustainably) in many poor and developing nations. In Africa, 20% of annual groundwater use is unsustainable; in Jordan and Yemen, the annual usage rate is 30%; and in Israel, 15%. In northern China, water tables are dropping nearly 5 feet (1.5 m) a year. In Tamil Nadu, India, the water table has dropped by 100 feet (30 m) in 30 years, and many of the aquifers there have run dry. Some of the world’s largest cities, including Beijing, Bue- nos Aires, Dhaka, and Lima depend heavily on groundwater. So much groundwater is being pumped from beneath Mexico City that parts of the city have sunk about 30 feet (9 m) since the 1900s. Groundwater mining takes place in developed nations as well. The Ogallala Aquifer irrigates more than 14 million acres (57,000 sq. km) of land beneath the breadbasket of the Midwestern United States and supplies water for the region’s cities and industries. On average, water is being pumped from the aquifer at eight times the rate it is being recharged, and the water table is dropping, in some areas as much as 3 to 5 feet (90 to 150 centimeters) per year. Some hydrologists estimate that one-fourth of the aquifer’s original supply of water will be depleted by 2020, and the water may be completely spent in those areas where the aquifer is already shallow. This level of water use is possible only in nations where there is infrastructure to gather and distribute large amounts of water. In many nations, people have to visit the village well or river to collect what they can in a pot. Each day, millions of women and young girls are forced to spend hours collecting and carrying water. The amount of work involved in supplying water to their families keeps girls out of school and women from helping with farm work or taking on outside employment. Civilizations can collapse when water becomes scarce. Over a period of about 1,200 years, the Maya constructed glorious pyramids, such as at Chichen Itza and Tikal, on the Yucatan Peninsula of Mexico and in the highlands of Guatemala. The Maya made important

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advancements in astronomy, the calendar, and in water management. Mayan farmers depended on annual rains from late spring to early fall for maize production and on their rulers to supply drinking and household water during the dry winter season. To meet the needs of their subjects, the Mayan elite learned to store water in reservoirs and to maintain its quality. Many anthropologists think that water was the

Women collecting water at Ho Lake Volta, Ghana. (Mark de Fraeye/Science Photo Library/ Photo Researchers)


means by which Mayan rulers maintained their power. Reservoirs, however, could only store water for a year or two. When a drought lasted longer than expected, and Mayan rulers could no longer supply their subjects with water, they lost the respect of the farmers they ruled and the civilization failed. Mayan farmers moved to other areas or, more likely, died of starvation and thirst. The Maya civilization collapsed around a .d. 900.

Sharing Limited Water Resources Boutros Boutros-Ghali, the secretary-general of the United Nations from 1992 to 1996, famously said the next war will be fought over water, not oil. His prediction was proven wrong by the most recent war in Iraq, but that does not preclude the possibility that some future wars will be fought over water. A total of 261 rivers, covering 45.3% of the total land area, are shared by two or more countries, but so far water conflicts have not resulted in fighting. Nonetheless, transboundary water resource management is extremely important and will become more so as the need for water grows. The Nile River basin is a good example of a region that could erupt in conflict over water at any time. According to the United Nations Education, Science, and Cultural Organization (UNESCO), “There is—apart from any differences caused by climate change—not a drop more water in the Nile River basin today than there was when Moses was found in the bulrushes. And there will not be a drop more in 25 years’ time, when the population living along the banks of the world’s longest river system is expected to have doubled to more than 300 million people.” Five of the 10 countries that share the Nile are among the world’s poorest. Ethiopia is a desperately poor country with more than 60 million people. This nation periodically suffers devastating droughts and massive starvation. If Ethiopia could irrigate its highlands, it could feed its people and keep down the erosion of its valuable soil during heavy rains. Yet, most of the Nile’s water is allotted to Egypt, as the result of an agreement that nation forged with Sudan in the 1950s.

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Even though Ethiopia was not party to the agreement and is located upstream from Egypt, the nation cannot take more Nile River water without risking a war with Egypt. To reduce the possibility of conflict and to better understand each others needs, the Nile nations have

The nations of the Nile River Basin.


approved the Nile Basin Initiative. These countries have agreed to begin to cooperate to find more equitable and legitimate use of Nile River water—for example, through increased efficiency in the methods used to retrieve it. Egypt, for example, is lining canals to keep water from seeping through, improving irrigation techniques, and reusing drainage water. Every drop of water in the Colorado River of the southwestern United States is allocated and managed. The Colorado River origi- nates high in the Rocky Mountains of Colorado and travels across the parched lands of Utah, Arizona, and into Mexico. Traditionally, about 90% of the water diverted from the Colorado River was for irrigation, much of it to California’s Imperial Valley, where in some years there is no measurable rain. But now the rapidly growing desert cities in Cali- fornia (Los Angeles and San Diego), Nevada (Las Vegas), and Arizona (Phoenix and Tucson) also compete for a share of Colorado River water. Various agreements have been signed to attempt an equitable division of water to the states and Indian reservations that depend on it. Still, by the time the river crosses the border into Mexico, there is often not even a trickle. Like 30% of rivers in the world, the Colorado River often no longer reaches the sea.

Wrap-up More than one billion people already rely on water that is being used unsustainably. Globally, between 5% and 20% of water use, including about 15% to 30% of the water being used for irrigation, is from sources that are not being replenished. Because water resources are a transboundary management problem, cooperation between nations and between states is needed to reduce the possibility of conflict.

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5 Problems with Water Use

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here is almost no place left on Earth where freshwater is completely free of contaminants. As described in this chapter, contamination comes from human and animal wastes, or agricultural or industrial effluent (also known as liquid waste). Pollutants can cause human illness and change the body’s response to its own natural chemicals. Pollutants cause natural bodies of water to lose oxygen. Ecosystem services are lost as waterways become polluted or engineered in such a way that the water system no longer supports natural ecosystems.

pathogens At present, 1.2 billion people lack access to clean water and 2.6 billion (about 42% of the world’s population) do not have basic sanitation facilities. About one- third of the world’s people live in a water- stressed country, where there is little access to clean water. Worst off is Afghan- istan, where 87% of the population faces this dire situation. Following 52

Problems with Water Use

close behind are the African nations of Ethiopia (76%), Chad (73%), and Sierra Leone (72%). Contaminants usually enter the water supply in wastewater, which is any liquid waste that comes from homes, businesses, industries, and farms. Sewage is wastewater that is made up of about 95% water and 5% human waste, such as feces and urine; pathogens, which are disease-causing microbes; harmful chemicals, and other substances. Wastewater may run or be piped directly into a stream, lake, or sea, unless it is treated first. In a wastewater treatment plant, the liquid is passed through a range of filters from large to very fine. Bacteria bio- degrade the organic material and chemicals, usually chlorine, kill the disease-causing organisms. (Material that is biodegradable can be broken down by bacteria into stable, nontoxic, inorganic compounds, such as carbon dioxide, water, and ammonia.) An effective wastewater treatment plant releases water effluent that closely matches the water quality of the stream or lake it pours into. Wastewater treatment plants are expensive to build and operate, and many nations cannot afford them or cannot maintain the ones they already have. In poor nations, and parts of some developing nations, an estimated 90% of wastewater is discharged into rivers and streams without treatment. Large cities release hundreds of millions of tons of raw sewage into local waterways each year. In some locations, the water in rivers and lakes is so polluted that it is unfit even for industrial uses. Still, between 1990 and 2004, the percentage of people in the world with basic sanitation increased from 35% to 50%, a net gain of 1.2 billion people. If there is no clean source of water, people will drink, wash in, bathe in, and cook with the contaminated water. Close to half the population in developing countries suffers at any one time from one or more types of diseases associated with dirty water. According to the World Health Organization (WHO), 3.2 million lives are lost each year to water-associated infectious diseases. People who consume untreated or inadequately treated water are likely to ingest the pathogens that cause waterborne diseases, which account for about 80% of all infectious diseases. Diarrhea is a common

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A child plays in polluted water in North Jakarta, Indonesia, in 2002. The number of children who have died from the health effects of polluted water is greater than all the people killed in armed conflicts since World War II. (OKA BUDHI/AFP/Getty Images)

symptom: About 4 billion cases of this condition occur each year. Single-celled pathogens cause diseases like cryptosporidiosis and cholera, both of which can kill victims who are unable to afford treatment. Parasites are organisms (such as flatworms, also known as blood flukes) that obtain nutrition from a host and can trigger diseases like schistosomiasis. Diseases can even result from the inability to wash properly: For example, trachoma, which to date has infected 84 million people worldwide and has blinded 8 million, can be prevented by simply washing in clean water. Whatever the sources of these diseases, the millions of adults who become sick from them are unable to work, perpetuating their poverty. Children who become sick due to these conditions suffer slow body growth and perform poorly in school.


In developed nations, water treatment plants are common. Still, untreated sewage may foul the waters in large cities where the sewage systems are now old and overextended, or when storms cause the wastewater to overflow. Raw sewage also runs into oceans. Some pathogens are resistant to treatment and may infect drinking water. Cryptosporidiosis, for example, has infected people in Georgia, Wis- consin, and New York in recent years. For the most part, however, water-related illnesses are uncommon in the developed world. When they do occur, they are promptly treated so they are rarely fatal, except in people with compromised immune systems.

Naturally Occurring Contaminants Arsenic is an extremely poisonous chemical element that is found in some rocks. Groundwater that flows through arsenic-bearing rock can become contaminated. In Bangladesh, an estimated 20 million people are drinking groundwater tainted with arsenic. Arsenic also contaminates the water for 2 million Chinese. China’s water is also tainted with naturally occurring fluorine, which affects the water supply for 63 million people. Brackish (somewhat salty) water is the only kind that is available for 38 million Chinese. Naturally occurring contaminants, in fact, are a problem in drinking water worldwide.

Pollutants from Intensive Agriculture and Industry In China, as in many other developing nations, poisonous effluent runs directly from industrial plants into the water supply. As a result, about 300 million Chinese drink water tainted by chemicals. In addition to this industrial effluent, chemical spills make their way into the water. In November 2005, a petrochemical plant explosion contaminated the Songhua River with nitrobenzene, a cancer-causing chemical. The water supply to nearby cities was cut off and people were warned not

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to eat the fish caught from the river. About 90% of China’s cities also have polluted groundwater. Among the sources of this pollution are the tanks beneath gas stations from which gasoline and the chemicals it contains leak into the ground.

Bangladesh’s Arsenic Tragedy The rock aquifers lying beneath Bangladesh contain high arsenic concentrations. This arsenic has made it into the water supply for many Bangladeshis. More than 14 million tube wells, about 29% of all wells in Bangladesh, contain water with arsenic levels higher than the guidelines established by the WHO. The result is that as many as 20,000 Bangladeshis die of arsenic poisoning each year. This tragedy has been caused by wellmeaning aid organizations. Before the wells were drilled, rural Bangladeshis drank sewage- contaminated surface water, which annually killed about 250,000 children. (Even now, bacterial pathogens kill about 110,000 children a year.) Aid organizations wanted to reduce the number of people who drank contaminated surface water, so they turned to groundwater. Although local people called the groundwater “devil’s water,” no one in the aid organizations tested it for arsenic. Arsenic in low levels poisons slowly, and the seriousness of the situation was not immediately realized. In the mid-1990s, large numbers of people began appearing

with signs of arsenic poisoning: tumors and blisters on the bottoms of their feet and on the palms of their hands. These blisters sometimes become gangrenous (when the tissue dies) or cancerous (when cell growth is uncontrolled). Internally, arsenic attacks the kidneys and lungs. Prolonged exposure is linked to several types of cancer, diabetes, skin thickening, numbness, partial paralysis, liver disease, and digestive system problems. Over time, the damage done by arsenic poisoning can be undone with clean water and nutritious foods, but most of the victims are too poor to have access to these commodities. Arsenic can be filtered out of the water, but many rural communities cannot afford the treatment technology. Research is being done on less expensive systems that exploit the affinity of arsenic for the magnetic mineral magnetite. When added to a bucket of well water, this mineral attracts the arsenic, which is then collected with a magnet and discarded. In the meantime, alternative water supplies are being constructed in the mostaffected areas.


Tap water in Shanghai, the nation’s largest and wealthiest city, runs yellow and smelly. Stinking, bubbling liquid oozes through the city’s canals. In some rural areas, residents have rioted to protest their chronic health problems and the destruction of their farmland and fish farms. China is currently spending tens of billions of dollars each year to improve its water treatment facilities and to fight water pollution. Water in the developed nations is much cleaner than it was in the 1940s, 1950s, and 1960s when the consequences of the growing population, agricultural intensification (techniques that intensify farming in an attempt to produce more food), and the growth of industry led to a precipitous decline in water quality. In the United States, many communities did not have wastewater treatment plants and so their sewage was piped directly into lakes and streams. Industrial waste also went straight into rivers and lakes or was buried in unlined pits that allowed rainwater to freely travel through into the water system. Industries had little incentive to clean the water they used before they released it. The situation came to a head in 1969 when the Cuyahoga River, a tributary of Lake Erie, caught fire as it flowed through downtown Cleveland, Ohio. The burning of the Cuyahoga River and other concurrent environmental problems led to the passage of the Clean Water Act of 1972 (amended in 1977). The act seeks to maintain the cleanliness of the nation’s waterways by reducing the discharge of pollutants, providing financing of municipal wastewater treatment plants, and managing polluted water. Since the act’s passage, United States’ surface waters are much less polluted. Even the Cuyahoga River has improved and the Environmental Protection Agency (EPA) has designated the river as one of 14 American Heritage Rivers deserving special attention for resource and cultural preservation. Pollutants, however, still contaminate the nation’s surface waters. According to the Natural Resources Defense Council (NRDC), at least 33% of rivers and more than 50% of lakes in the United States are so contaminated that they are unfit for swimming, fishing, and other uses. Besides overflow from wastewater treatment plants, many of the

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contaminants that have come into use since passage of the Clean Water Act are not regulated by the act. Groundwater is also not protected by the Clean Water Act. Con- taminated fluids standing in ponds and in agricultural fields, trickling through landfills, and leaking from underground storage tanks (including gasoline tanks) filter through the soil and rock into groundwater aquifers. In Florida, where 92% of the people drink groundwater, more than 90% of the wells have detectable levels of industrial and agricultural chemicals and more than 1,000 wells have been closed. Common pollutants include artificial fertilizers and chemicals that are used for a variety of agricultural and industrial purposes. When more fertilizer is placed on a field than the plants can use, the excess runs off into the water supply, where it becomes nutrients for algae and other aquatic plants. In cases where there is a lot of excess fertilizer, the plants bloom explosively: When they die, the bacteria population increases dramatically to consume the dead tissue. The bacteria use up all the oxygen in that region of the water body, a process called eutrophication. These oxygen-poor waters become dead zones, regions that are hostile to most forms of life. Fish and invertebrates (animals without backbones) die off or move away, harming the food supply for people living in the area. Chemicals used as gasoline additives, pesticides, insecticides, solvents, and flame retardants, among other uses, all find their way into the water supply. Some 70,000 different chemical substances are in regular use throughout the world, and every year an estimated 1,000 new compounds are introduced. Some have been proven to be damaging to ecosystems or to human health and have been banned. The insecticide DDT (dichlorodiphenyltrichloroethane) was banned in the United States in 1973 (and elsewhere later) after having been found responsible for a huge drop in populations of some birds, including peregrine falcons (Falco peregrinus), bald eagles (Haliaeetus leucocephalus), kingfishers, and barn owls (Tyto alba). DDT exposure caused the birds to lay eggs with extremely thin shells that would break when the mother birds sat on them. Populations of these birds have steadily recovered since the chemical was banned.


Some chemicals may be harmful to people or other organisms in miniscule quantities. Some of these chemicals mimic chemicals naturally found in the human body that control physiologic functions. Endocrine disruptors, for example, can become a substitute for hormones that regulate many of the body’s functions, including growth, development, and maturation. Hormone disruption by endocrine disruptors can also damage immune systems. Since endocrine disruptors are present in water, aquatic animals like fish and amphibians have been the most affected. These animals may develop poorly and have misshapen and undersized sex organs, the numbers of males and females born may be skewed, and the size of the population may be reduced. In mammals, males exposed to estrogens (female sex hormones) do not develop correctly sexually, or they have limited reproductive success. Some researchers think that exposure to endocrine disruptors may be at least partly responsible for declining sperm counts and increases in testicular cancer in men and menstrual problems, decreased fertility, and miscarriage in women. The Centers for Disease Control and Prevention (CDC) has discovered a decline in fertility in all human age groups, but the decline is sharpest in women under age 25, the group that has been most exposed to these chemicals during child- hood. Experiments on laboratory animals suggest that environmental toxins could be the cause. In a Canadian aboriginal community that lives adjacent to a heavily polluted industrial complex, only 35% of the babies born in 2003 were boys: This was a large drop from the normal sex ratio that was measured before 1993. While a cause has not been identified, endocrine-disrupting chemicals have been shown to skew sex ratios in lower animals, and these chemicals are found at relatively high levels in the region. 20,000 households in a wider study of 90 Canadian communities with elevated exposure to industrial air pollution had a sex ratio of 46 boys to 54 girls (the normal ratio being 51:49). Some of the many types of toxic chemicals are as follows: 

Phthalates, which impart viscosity, flexibility, and softness in plastics, are endocrine disruptors. In one recent study, some

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human male fetuses that had been exposed to phthalates experienced problems with penis development. Phthalates have also been linked to premature breast development in girls. About one billion pounds (450,000 metric tons) of phthalates are produced worldwide annually.  Persistent organic pollutants (POPs) is a large class of toxic chemicals found in some pesticides, flame retardants, industrial solvents, and cleaning fluids. POPs in humans are linked to cancer; liver, immune, and nervous system damage; skin problems; stillbirth; and reproductive problems. POPs travel easily through the atmosphere and water systems and do not break down or disperse into the environment. POPs also bioaccumulate in the food web so that top predators contain high concentrations. (Bioaccumulation is the process where a predator absorbs into its body all of the chemicals from each of the hundreds or thousands of prey that it eats during its lifetime, with the result that the chemical becomes extremely concentrated.) Polar bears and people in the Canadian Arctic have high concentrations of POPs.  Most heavy metals are present in some concentration naturally in the environment. All of them are toxic to humans in some dose, some in tiny quantities. Heavy metals are released by the burning of coal, fuel oils, fuel additives, and trash, in addition to steel and iron manufacturing. Once in the air, heavy metals can rain out into the waterways. Mercury in its organic form is probably the most damaging heavy metal. In humans, it causes brain, liver, and kid- ney damage. The recognition of the dangers of mercury to human health resulted in a great decrease in global mercury production beginning in 1990. Most toxic chemicals have only appeared on the scene since the 1940s and more types are released in greater quantities each year. In the United States alone, about 3 million tons of toxic chemicals


Emissions of organic water pollutants by nation, 2004. The more-developed and rapidly developing nations tend to use greater amounts of organic chemicals than the lessdeveloped nations. In UNEP/GRID-Arendal Maps and Graphics Library.

are released into the environment each year. Babies born today are exposed to thousands of chemicals simultaneously starting at conception: Harm to the sperm and eggs due to these chemicals may start even sooner. Some of these chemicals are known to have deleterious effects on individual cells or animals in lab experiments, while many other substances have not been studied. These toxic chemicals are thought to contribute to cancer, birth defects, immune system defects, and many other serious health problems. The effects of these chemicals when they are mixed together have been studied in only a few cases, even though that is how they show up in the environment.

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Loss of Ecosystem Services The more water people use for their own purposes, the less of it is available for ecosystems. According to the World Resources Institute (WRI), freshwater ecosystems have the highest proportion of species that are threatened with extinction. The loss of species diversity within an ecosystem (also called its biodiversity) is increased by the decline of wetlands and the degradation of inland water quality. More than 20% of the world’s species of freshwater fish have become extinct, endangered, or threatened. Extinction rates for aquatic species could be as high as five times greater as those for terrestrial species. An endangered species is any plant or animal species whose ability to survive and reproduce has been jeopardized by human activities. A threatened species is one that is likely to become endangered. The construction of dams causes irreversible changes in many of the ecosystems that are associated with them: For example, by converting a river ecosystem to a lake ecosystem. Dams bring about the loss of freshwater habitat, particularly floodplains and wetlands. Large dams may affect habitat for more than 600 miles (1,000 km) down- stream. The Colorado (derived from Spanish for “color red”) River once ran warm and muddy through the desert southwest. Since 1963, the river has been corralled by the Glen Canyon Dam in northeastern Arizona, upstream from the entrance to the Grand Canyon. When the river emerges below the dam, it is free of sediments, debris and nearly all nutrients, plus it runs much colder. Populations of its native fish have decreased, and species of trout and other game fish have been introduced into the reservoir behind the dam. Several bird species, including the Southwestern willow flycatcher (Empidomax traillii extimus), have also declined in number in recent years. Dams also change the human ecology of a region. Over the past 50 years, dams have displaced some 40 million to 80 million people in different parts of the world. Around the world, enormous areas of wetlands have been drained, mostly for farmland. California has lost more than 90% of its wetlands. As a result, nearly two-thirds of this state’s native fish are extinct, endangered, threatened, or in decline. Forested riparian wetlands near


the Mississippi River once had the capacity to store about 60 days of river discharge, which greatly reduced damage during flooding. Wetlands removal has reduced storage capacity to about 12 days of discharge. Without wetlands, nutrients and other pollutants make their way more readily to streams, lakes, and oceans.

Wrap-up People use water to dispose of waste. Human and animal waste, agricultural waste, and industrial waste all make their way into bodies of water at the surface and below ground. In recent years, the number of people, farms, and industries that dump pollutants into water has exploded. Many people do not have access to proper sanitation and their water is contaminated with pathogens that cause disease. Wherever there is intensive agriculture and industry, nutrients and chemical pollutants contaminate the water. Progress has been made in the developed nations, where legislation like the Clean Water Act requires that municipalities and industries keep surface waters clean. Not all chemicals are covered by the act, however, and groundwater remains unprotected. These pollutants also lead to the loss of ecosystem services. Dam construction also has a significant impact on the water supply.

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6 Sustainable Water Use

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he rising population and improving lifestyles of the developing nations that are predicted for the first half of this century will increase the water needs of the human inhabitants of the planet. Already many people live without access to clean water and many others rely on water that is being used unsustainably. In the twentieth century, water was collected and distributed using dams, canals, and other “hard” structures. As discussed in this chapter, while these have been very useful, they are also expensive and environmentally damaging. “Soft” solutions to the problem of water scarcity, particularly increased efficiency, will provide a less expensive and less damaging path for the twenty- first century.

fUtUre Water needs Nearly half of all people live in countries that contain regions with insufficient water. Even the problems of today, however, will be com- pounded many times in the future. Between 2000 and 2020, water use is expected to increase by 40%. In China, where water is already 64

Sustainable Water Use

Freshwater stress, as measured by the amount of water withdrawn as a percentage of the total water available, was highest in North Africa and the Middle East and moderate in India, Mexico, central Asia, southern Africa and parts of Europe in 1995. By 2025, water stress will be high in more of Africa, the Middle East, central Asia, India, the United States, China, and more of Europe.

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scarce, industry is expected to need six times more water in 2020 than it did in 2000. By 2050, more than 2.8 billion people worldwide will be affected by water shortages, or about 35% of the population. Populations are growing rapidly in nations that are already unable to meet their residents’ water needs. In impoverished regions such as sub-Saharan Africa, economic and technological constraints may continue to keep supply from meeting demand. Lifestyle improvements in developing and, to a lesser extent, poor nations will also increase the demand for water. Even countries with ample water in some locations will have regions without enough water, including Mexico and the United States. Some people think that a water crisis in poor arid countries with rapid population growth is inevitable. These predictions do not take into account global warming, which will alter climate patterns. As is already happening, some regions will receive more precipitation and some less. If areas that get more precipitation receive it in large storms, as is predicted, much of the water will run off the land without being put to use. Global warming is predicted to increase temperatures and reduce snowfall in several mountainous regions, causing a loss of usable water. In California, winter snows are like a bank that saves water for the dry summer months. California’s major cities rely on this water, as do farmers in the fertile Central Valley. If there is less snow and snowmelt comes too rapidly in the spring as is predicted, the water may not be available in the summer when it is needed most. The people living below the glaciers of the Peruvian Andes rely on snow and ice melt for their water during the dry summers. Since 1972, however, the glaciers have lost about 20% of their mass, and by the end of this decade some will be gone or too small to provide much melt water. The glaciers of the Hima- laya Mountains—which feed seven rivers that provide more than half the drinking water for 40% of the world’s people—are also melting back.

Solving the Water Problem Earth has a lot of freshwater, but it is not always found where it is needed. In the twentieth century, water resources were exploited by what Peter Gleick, the head of an environmental think tank called the


Pacific Institute, calls “hard” solutions: dams, aqueducts, reservoirs, and centralized wastewater treatment plants. These engineering solutions were enormously successful in allowing agriculture and development to take place where there was originally not enough water and in allowing the recycling of used water. Hard solutions to water problems are expensive, and many countries and municipalities do not have the money for them. In addition, they sometimes have negative consequences. When it is completed, the enormous Three Gorges Dam on China’s Yangtze River, for example, will flood 395 square miles (632 sq. km) of land, displacing 1.2 million people from nearly 500 cities, towns, and villages along the river. Magnificent scenery and irreplaceable architectural and archeo- logical sites will be lost. By drilling wells, groundwater can provide more water in some locations, but in many other areas, aquifers are already overexploited. Drilling into deeper aquifers has also been suggested, although this solution will be expensive and ultimately not sustainable. Arid and semi-arid nations with access to inexpensive energy look to the oceans as a source of water. The desalination process supplies water only for the nations that can afford it. Desalination is expensive because it requires a lot of energy. In the Middle East, where energy is abundant, desalination is the only feasible way to acquire cleaner, fresher water. Kuwait built the first large-scale desalination plant in the 1960s, and now more than 50% of its total water comes from the sea. The United Arab Emirates gets 16% of its water from desalination, while Saudi Arabia gets about 4%. In the United States, where desalinated seawater costs five to eight times as much as con- ventionally treated water, less than 1% of drinking water comes from desalination. There are two methods of large-scale desalination. In distillation, seawater is heated until the water evaporates, leaving the salts behind. The water vapor flows into a separate container where it condenses. To reduce the amount of fuel needed for heating, the water is placed under pressure to lower its boiling point. The multistage flash distillation process, used in more than 2,000 desalination plants, uses pressure differences to cause seawater to boil so rapidly that it flashes into

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steam. One plant in Saudi Arabia produces 250 million gallons (946 million l) of freshwater daily this way. Most future desalination plants will use reverse osmosis. With this process, saltwater is forced at high pressure through a permeable membrane, allowing the pure water to pass through, while the salts are left behind. This process also removes some contaminants like bacteria and some harmful chemicals. Reverse osmosis is much less energy intensive and only half as costly as flash distillation. Desalination plants use a tremendous amount of water. For every 15 to 50 gallons (57 to 190 l) of pure water produced, 100 gallons (380 l) of seawater are needed. The waste product is a brine contain- ing dissolved salts, chemicals used to keep organisms from growing on the plant surfaces (known as antifouling chemicals), and toxic

Biography: Dr. Peter Gleick Dr. Peter Gleick is one of the few people in the developed world who recognizes the enormous problems that many of the world’s people face every day in acquiring safe water. As the head of the Pacific Institute, an environmental think tank that explores the links between water issues and environment, economic development, and international security, Gleick is a recognized expert on issues such as the hydrologic impacts of climate change, sustainable water use, privatization and globalization, and international conflicts over water resources. Although he grew up in New York City, Gleick developed a deep love of the outdoors and the environment. While working on a degree in engineering and applied science at Yale University, Gleick became

interested in the intersection of science and policy, particularly regarding energy and the environment. His 1986 doctoral dissertation, completed at the University of California, Berkeley, was one of the earliest studies of the effects of global warming on water systems. In 1987, Gleick, along with two friends and colleagues, founded the Pacific Institute. Now the institute’s president, Gleick says there are two reasons water issues are not talked about as much as energy issues: The worst water problems are in developing countries, out of sight of the United States and other developed nations. Additionally, water resource issues are largely regional. Since nations rarely depend on foreign governments for water, the issue is not as politically


metals. The brine is so salty that it can harm marine ecosystems when it is released into the sea. In the United States, the Environ- mental Protection Agency (EPA) classifies these brines as industrial waste. Despite receiving abundant rainfall—about 53 inches (135 cm) a year—rampant growth has caused Florida to search for extra water. Since much water for new residents is coming from overuse of groundwater, the state has begun to build desalination plants. The Tampa Bay plant, the largest in the Northern Hemisphere, has the capacity to produce 25 million gallons (95 million l) of freshwater a day. Although its water is the least expensive desalinated water in the world, it is still four times more expensive than the local groundwater. This reverse osmosis plant is currently being rebuilt with many environmental

charged as other resource issues, such as those surrounding oil. Nonetheless, political disputes and tensions over water are worsening in many places. Gleick said in a 2006 interview with this author, “We need to better understand the risks of conflicts over shared water resources if we are to be able to avoid such conflicts in the future.” In the 20 years the Pacific Institute has been in existence, its goal has always been to improve our understanding of the ways in which environmental challenges, poverty, and security interconnect with each other, and to develop practical solutions to those challenges. Gleick sees the future as a time of “doing what you want with less water.” Conservation and efficiency are essential to cutting back on the

total use of water, without cutting back on the benefits that water provides. Also, increasing the availability of safe water to all people must be done without depriving the natural environment of the water that is critical for its health. “Indeed, the health of the environment is vital for the health of people as well. But we need to speak out for the environment, which has no voice in the corporate or political world, and hence, loses water it needs when humans make decisions about development.” Gleick is happy with the path he has chosen: “I love my job where I can read, think, and write about global water problems and how people can solve them. And I love talking to people about water— everyone cares about water, deeply, and I find receptive audiences everywhere I go!”

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protections; its salty effluent, for example, will be diluted with cooling water from a nearby electric power station. Hard solutions to the water problem are expensive, sometimes energy intensive, and often environmentally damaging. Peter Gleick offers another set of solutions, which he calls “soft” solutions. All nations use water inefficiently: In some developing countries, 62% of water meant for irrigation is lost to leakage and evaporation. For example, about half the water destined for Nairobi, Kenya, is lost to leaky pipes, or is stolen by farmers. Cities such as Mexico City, Seoul, and Tehran cannot account for about one-third of the water that is destined for use there. The cheapest and least environmentally damaging way to increase the amount of available freshwater is to raise efficiency. This can be a tremendous source of water. According to Gleick, Mexico City replaced 350,000 leaky toilets with more-efficient ones and saved enough water for 250,000 new residents. Improved sanitation can also increase the amount of water available to poor and developing nations. Water for irrigation can be collected and used much more efficiently than it is now. Simple earth walls can trap rainwater for later use on crops. Rainwater can also be trapped as it runs off developed land and allowed to trickle into the ground to recharge the underlying aquifer. Flood irrigation, which floods entire fields with water, can be replaced by drip irrigation, which trickles water slowly onto the roots of plants and produces higher yields with less water. Farmers of arid regions can choose drought-resistant crops. Some people suggest that water-rich crops can be grown in rainy regions and shipped to arid locations where they can offset the amount of drinking water people need, but shipping crops long distances would require enormous amounts of energy. In developed countries, increased efficiency can stabilize or even reduce demand for water. Already, per-capita water consumption in developed nations has dropped in the past two decades. Water use in the United States, for example, was at a high of about 1,900 gallons (7,200 l) per person in 1980, and dropped to about 1,620 gallons (6,100 l) per person in 1990, and 1,430 gallons (5,400 l) per person


Water withdrawals and GNP for the United States through the 20th century. While water use and GNP are well linked for the early and middle potions of the century, in the late 1970s, water withdrawals began to lessen while GNP continued to rise. This nation’s economy and population are growing, but water use is shrinking. Data from the Pacific Institute.

in 2000. The drop was due to increased efficiency in irrigation systems and domestic households, such as the introduction of low-flow toilets. According to Gleick, the Clean Water Act of 1972 is responsible for much of the decrease in water use. Once industries were made responsible for cleaning up the water they polluted, they determined that it was easier and cheaper not to pollute the water in the first place: This made them more-efficient water users. Whereas it used to take 200 tons (181 metric tons) of water to make one ton (0.91 metric tons)

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of steel, it now takes five or six tons (4.5 or 5.4 metric tons) to make the same amount. “One of the bright spots in the world of water,” said Gleick in a 2007 interview with this author, “is the fact that we are slowly awak- ening to the problems that face us and slowly moving toward moreefficient, less-wasteful use of water. We are learning that we can do what we want to do (grow food, make widgets, clean, drink, and produce) with less water than we currently use. As a result, the United States is actually using less water today for everything than it did more than 20 years ago, and much less per person! We are doing more with less. And there is far more that can be done to save water and use it efficiently.” Conservationists agree that the best way to encourage conservation is to increase the price of the commodity that needs to be conserved. For example, the price of water should include the ecosystem services that the watershed (which is all of the land drained by a river and its tributaries) provides. If an ecosystem is damaged to the point where it can no longer provide services, such as flood control or pollution filtration, the job must be done using a human-constructed system. Portland, Oregon; Portland, Maine; and New York City each found that it would cost between 7 and 200 times as much money to construct water treatment facilities as it would cost for watershed protection. To encourage conservation, Gleick says that farmers should be charged the true cost of the water they use rather than the subsidized amount they currently pay. Increasing the price farmers pay for water would provide them with incentives to adopt water-saving technologies, like drip irrigation. A similar scheme in Chile reduced water use and saved money that would otherwise have been spent for infrastructure to supply new water sources for other users. Farmers in the arid and semi-arid regions of the United States could be encouraged to grow less-water-intensive crops. Vegetables, fruits, and nuts use less water than cotton, alfalfa, rice, and irrigated pasture (for beef), and they have higher value. To protect a nation’s water supply from pollution, regulations must be put into place and enforced. Charging polluters for their effluents


would force them to pay the real cost of their business, rather than allowing them to pass that cost along to other water users, or allowing the system to further degrade. A cap-and-trade system could be implemented for some pollutants in the United States, such as nutrients. In such a system, a country-wide “cap” would be set for annual phosphorous and nitrate runoff. Program participants would receive allowances for the amount of nutrients that they are permitted to discharge each year. The allowances could be used, traded to another participant, or banked for future use. Since allowances can be traded for cash, people have a monetary incentive for reducing nutrient use. To be sure emissions lessen over time, the cap would be lowered.

Wrap-up Climate changes and population growth together could leave as many as 7 billion people in 60 countries facing a water shortage by 2050. To avert a water crisis that could cause starvation and thirst for millions of people, governments should take action to stop wasting and polluting fresh water sources. As Peter Gleick said in a 2007 interview with the author, “Solving the problem of providing complete access to safe water and adequate sanitation is not a technical problem. Nor is it a financial problem. We have enough money and the right kinds of solutions. What we seem to lack is governmental commitment and will. Everyone on the planet could have safe water and sanitation if we decided, collectively, that this was a priority.”

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PART THREE

ENERGY RESOURCES

7 Energy from Fossil Fuels

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his chapter focuses on fossil fuels, which currently provide about 85% of the world’s energy. Fossil fuels have driven the incredible economic and population expansion of the past one- and-a-half centuries. While running out of fossil fuels is not imminent, they are likely to become more expensive as the remaining deposits are more difficult to access for political, technological, and environmental reasons.

Fossil Fuels Most of the energy used today is from coal, petroleum, and natural gas. These fossil fuels are located in rock at or beneath the land surface, sometimes even below the seafloor. Coal forms from decayed and partially decayed plants that were buried at great enough depths in the Earth to be compressed and transformed into rock. The more heat and pressure the organic material experiences, the higher quality coal it

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becomes. Miners access a coal seam by stripping away all the rock and plants that lie above it, a process called strip mining, or by creating underground caverns to expose the desired material. Petroleum, or crude oil, forms below the seafloor where the bodies of large numbers of tiny marine organisms (mostly single-celled plankton) sink and become buried by sediments. As with coal, burial raises the material’s temperature and pressure, converting it to crude oil. In a permeable rock, the oil rises until it becomes trapped by an impermeable rock layer, where it can be drilled and pumped to the surface. The crude oil is then transported to a refinery where it is chemically treated and heated under pressure, which converts it to propane, gasoline, heating oil, or other distilled oil that is useful for petroleum-derived products such as plastic and nylon. If, while it is buried, the crude oil’s temperature exceeds 212°F (100°C), the boiling point of water, the heat converts it to natural gas. This gas may float on top of the heavier crude of a petroleum deposit, or it may migrate into a separate reservoir. Natural gas is cleaner and more energy efficient than petroleum and does not need to be refined. Because of this, natural gas is less expensive than oil. In some locations in the Middle East and elsewhere, natural gas is present in petroleum deposits in such small quantities that it is flared off rather than pumped. If oil cannot move through the rock but remains trapped, the rock becomes oil shale. Oil shale is mined in open pits. This rock is crushed and heated to very high temperatures (between 840°F and 930°F [450°C and 500°C]) and then washed with enormous amounts of water. This process converts the fuel to petroleum, which then is extracted from the rock. Tar sands are rocky materials mixed with very thick oil. Because the tar is too thick to pump, tar sands are strip mined. Separating the oil from the rocky material requires processing with hot water and caustic soda. When this slurry is shaken, the oil floats to the top, where it can be skimmed. Oil shale and tar sands are just coming into use as an energy source. Producing oil from oil shale or tar sands creates an enormous amount of waste rock.

Energy from Fossil Fuels

Fossil Fuel Use Today The inhabitants of poor and developing nations usually burn wood or coal directly for heat, light, and for cooking food. (Unlike coal, wood is a biofuel, a type of fuel that harnesses the Sun’s energy stored in plant and animal tissue.) Industrialized nations depend almost entirely on fossil fuels for energy. Fossil fuels are highly utilized because they are readily available, plentiful, easily recovered and stored, and com- paratively inexpensive. They are relatively well concentrated so that a large amount of power can come from a small amount of fuel. Because of these advantages, technologies were developed to use fossil fuels and the machines that use them are long established and widespread. Gasoline is especially important because it is one of the few energy sources available as a liquid, which allows its use in cars and trucks. Natural gas is used for home heating, cooking, and fueling electrical generating plants. In industrialized nations, people use energy in two forms, as electricity and as a liquid, like gasoline. Electricity is needed to heat houses and run computers, among many other tasks. To generate electricity (or any other type of energy that can heat water) from fossil fuels, the fuels are burned to create steam in a steam-electric power plant. The steam turns a turbine that is connected to a generator, which supplies the electricity. In newer power plants, the burning fuel releases gases that turn the turbine directly. Liquid fuels are needed for use in internal combustion engines, as in cars, and may also be used for heat. The world’s energy consumption is growing, mostly in fossil fuel use. Between 1950 and 2004, the use of oil increased 8 times, coal increased 2.6 times, and natural gas increased 14 times for a 523% total increase in fossil fuel use. Recently, the strongest growth in fossil fuel use has been in the Asia-Pacific region, where fuel use in 2005 was up 5.8%, with China alone accounting for more than half the growth in global energy consumption, most of it in coal. Coal, petroleum, and natural gas currently provide more than 70% of the energy consumed in the United States. Though accounting for only 5% of the world’s population, Americans consume 26% of the world’s

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World consumption of fossil fuels grew astronomically between 1950 and 2005.

energy. Transportation accounts for 28% of energy use in the United States. While the number of miles of new roads built in the country over the past 20 years has gone up less than 5%, the average number of miles Americans travel in their cars has increased 81%. In 2005, North America had the weakest growth in fossil fuel use of any world region, only 0.3%, and consumption in the United States fell slightly.

Running Out of Fossil Fuels Because fossil fuels are nonrenewable resources, they will eventually run out. Although there is much disagreement among experts on when that will happen, the following statistics were presented by Steven E.


Koonin, chief scientist of British Petroleum at the State of the Planet 06 conference. He suggests that there are 40 years of proven oil reserves at current production rates and possibly another 40 years that are as yet undiscovered. Natural gas has about 70 years proven and possibly another 70 to be discovered. Coal has 160 years proven and probably at least six times as much because not much has yet been done to look for new deposits. If needed, new technologies could exploit lower grade coal or coal waste that had been previously unusable. Although there is still oil left to exploit, that oil is lower grade, harder to get to and extract, and is often located in politically volatile locations. For these reasons, oil prices are rising. To separate the political and technological/environmental causes of rising fuel prices, economists take into account the cost of producing the energy. When an oil deposit is easy to exploit, the energy return on investment (EROI) is about 25 to 1, as it was in the early 1970s. Today, the average EROI is about 15 to 1. Increasingly, exploration yields little additional oil. In 2003, according to Thomas Homer-Dixon, director of the Trudeau Center for Peace and Conflict Studies at the University of Toronto, companies spent $8 billion on oil exploration but only found $4 billion worth of oil. Many people think that tar sands and oil shale will satisfy future fossil fuel needs. On the positive side, the deposits are in politically favorable locations, and they are large. The amount of fuel available as oil shale is comparable to the amount remaining in conventional oil reserves, with 60% to 70% of it located in the United States. The amount of fuel in tar sands is equal to about two-thirds of the world’s total reserves of oil: Most of these reserves are found in Alberta, Can- ada, with some in Venezuela. On the negative side, these fossil fuels have an EROI of only 4 to 1. Such low profits reduce a nation’s ability to maintain or improve its standard of living. Joseph Romm, executive director of the Center for Energy and Cli- mate Solutions, said at the State of the Planet 06 conference, “Canada is now getting a million barrels a day from the tar sands. [With] the tar sands you have to waste a lot of natural gas heating them up to turn them into oil. So instead of exporting natural gas to us to displace coal

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plants, they are wasting it making carbon intensive liquid fuels. It is a really, really bad idea.”

The Politics of Oil Use Fossil fuels are not evenly distributed around the globe, and because they are so essential to the modern economic structure, the nations that have abundant sources of them have political and economic lever- age over those that do not. The greatest oil reserves are located in the Persian Gulf, an especially volatile region of the world. The United States spends more than $25 billion a year on Persian Gulf oil. The United States hit its peak oil production in 1971 and has been declining since. Oil imports, however, are steadily increasing. In 2000, the United States imported 58% of its oil, a number that rose to 66% in 2005. While the political ramifications of oil dependency are well beyond the scope of this book, recent history has shown that depending on a volatile region of the world to supply an essential commodity is fraught with problems. Reducing oil consumption would have important economic and political implications: It would reduce the trade deficit (the amount which the value of a nation’s imports exceeds the value of its exports) and reduce the nation’s dependence on foreign governments. Many people call for increasing domestic oil production, but there are few areas that have not yet been exploited. One of these remaining areas, the Arctic National Wildlife Refuge (ANWR), has been called America’s single largest untapped source of oil. Drilling in this wildlife refuge has been controversial for decades. In 1998, the United States Geological Survey (USGS) estimated ANWR’s technologically recoverable oil at between 4.3 billion and 11.8 billion barrels (mean value 8.05 billion barrels). With the United States currently consuming about 20 million barrels of oil each day, ANWR would meet the nation’s total oil use for between 215 and 590 days (mean value 402.5 days, slightly more than one year). An unknown quantity of oil lies in the ground beneath the Arctic Ocean. The USGS estimates it to be one-quarter of the world’s undiscovered oil and gas reserves, and


e xploration is ongoing. Portions of the nations of Russia, Canada, United States, Greenland (a territory of Denmark), Iceland, Norway, Sweden, and Finland are located in the Arctic. Russia is beginning to search the far north for oil.

Wrap-up While the world will not run out of oil and gas for a number of decades, the price of petroleum will continue to increase as the remaining deposits are more difficult to exploit and are located in areas that are politically volatile. Coal will last for centuries, and China will increasingly rely on its enormous coal reserves. Tar and oil shale could become more important as a future source of oil in the future, but both have low EROIs and are environmentally destructive. The biggest unknown in oil reserves is what lies beneath the Arctic Ocean, which will undoubtedly be the focus of intense exploration in the coming years.

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8 Problems with Fossil Fuel Use

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s fossil fuel use has increased, so has people’s awareness of its costs, which are the focus of this chapter. The pollutants that are given off by fuels when they are burned pollute the air and water and cause acid rain and global warming. Although the effects of global warming are already being seen, efforts to curb greenhouse gas emissions have not been very successful so far.

aiR PolluTion Fossil fuel burning contaminates the atmosphere with gases and other substances in quantities that may be harmful to human health and the environment. Nitrogen oxides, sulfur oxides, carbon monoxide (CO), and hydrocarbons (organic compounds composed of hydrogen and carbon) are among the gases released directly into the atmosphere when fossil fuels are burned. Particulates, like soot, are also air pollutants. Photochemical smog is not emitted directly into the air, but forms

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Problems with Fossil Fuel Use

A factory spews air pollution, contaminating the atmosphere with substances harmful to the health of people and of the environment. (Alexy Samarin/Dreamstime.com)

when sunlight reacts with other pollutants to create ozone (O3) and other polluting substances. Lead is a heavy metal that was once added to gasoline to improve its efficiency but is now present only in diesel fuel in the developed nations and in gasoline in some developing nations. The Environmental Protection Agency (EPA) estimates that Ameri- cans send more than 160 million tons (145 million metric tons) of air pollutants into U.S. airways each year, causing reduced visibility and health problems. Most of the effects that people experience from air pollution are short term: irritation to the eyes, nose, and throat; head- aches; nausea; allergic reactions; or upper respiratory infections, such as bronchitis and pneumonia.

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But there are also longer-term effects. The incidence of asthma in children ages 5 to 14 in the United States increased nearly 2.5 times between 1980 and 2005, which may be partially related to air pollution. One California study showed that children who lived in a city with high ozone pollution and played three or more sports had a much higher incidence of asthma than other children. One study tracked 500,000 people in more than 100 U.S. cities for 15 years and showed that not only did the risk of a nonsmoker dying from lung cancer rise with increasing pollution, but that no level of air pollution could be considered safe. The study also found that the longterm effects of breathing heavily polluted air are the same as those from breathing second-hand tobacco smoke (the reason that many establishments no longer allow smoking). The risk of dying from heart disease, or of dying from any cause, increased with higher air pollution levels. The Natural Resources Defense Council (NRDC) estimates that 64,000 premature deaths from cardiopulmonary (heart and lung) illnesses may be attributable to particulate pollution each year. Fine particle pollution emitted from power plants each year causes more than 30,000 deaths and more than 603,000 asthma attacks. Despite these sobering figures, air pollution has gotten much better in the developed nations where clean air legislation has been enacted. In the United States, the Clean Air Act of 1970 established standards for ambient air quality, set emissions limits, empowered state and fed- eral governments to enforce standards and limits, and increased fund- ing for air pollution research. The law was updated in 1990 to make emission requirements stricter. The Clean Air Act now regulates 189 toxic air pollutants, alternative fuels, and also monitors the pollutants that contribute to acid rain and stratospheric ozone depletion (including the Antarctic ozone hole). Still, while industrial smog has been on the decline in the United States since the act’s passage, levels of photochemical smog continue to rise. In the developing world, there are few if any regulations on air pollution and the increasing numbers of people and activities that pollute the air. Of the 20 most polluted cities in the world, 16 of them are in China. Indeed, in 2006, China not only pushed Mexico City out of its


top spot as the most polluted city in the world, where it had been for decades, but knocked it out of the top 10 altogether. Globally, air pollution is thought to kill about 3 million people a year. In wet air, the nitrogen and sulfur oxides emitted by fossil-fuel burning combine with water (H2O) to form nitric acid (HNO3) and sulfuric acid (H2SO4). When these droplets come together, they form acid rain, which is considerably more acidic than normal rainwater. Acid rain makes stream and lake water more acidic, which can harm or even kill aquatic organisms. Acid rain strips the soil of its nutrients and damages trees by harming their leaves and needles and reducing their nutrient supply. Large amounts of acid rain can seriously alter an aquatic ecosystem. Acid rain takes a toll on stone buildings and other structures that are culturally significant, including the United States Capitol building in Washington, D.C.; St. Paul’s Cathedral in London; and Egypt’s temples at Karnak.

Global Warming The debate is now over: Nearly all climate scientists say that the greenhouse gases that are released by fossil-fuel burning are largely to blame for increasing global temperatures. As NASA’s James Hansen, often called the country’s leading climate scientist, said in Science, in April 2005, “There can no longer be any genuine doubt that humanmade gases are the dominant cause of observed warming.” CO2 is the most abundant greenhouse gas: It is also the one that is increasing most rapidly. Plants store CO2 in their tissue, where it remains when the plants are converted into coal, oil, or gas. When these fossil fuels are burned, the CO2 is emitted into the atmosphere. Since that CO2 had originally been stored, or sequestered, in the ground, adding it into the atmosphere increases the atmosphere’s CO2 content. Of the three main fossil fuels, coal produces 45% more CO2 than natural gas, while petroleum produces 30% more. Tar sands and oil shale emit about the same amount of CO2 as coal. Atmospheric CO2 has risen 27% from a preindustrial value of 280 parts per million (ppm) to the 2007 value of 382 ppm; nearly

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65% of that rise has been since CO2 values were first measured on Mauna Loa volcano in Hawaii in 1958 (the value at that time was 316 ppm). Other greenhouse gases, particularly the hydrocarbon gas methane (CH4), have also increased. Elevated greenhouse gases levels were a major factor in driving up global temperatures by 1°F (0.6°C) between 1900 and 2000. Of that increase, 70% (0.7°F [0.4°C]) has occurred since the 1970s, with a major upswing taking place during the 1990s. Recent scientific evidence shows that the past 10- to 20-year period was the warmest period of at least the past two millennia. Not all nations of the world are equally responsible for greenhousegas emissions. The United States is the largest emitter (24% of the

Average measured temperatures from 1880 to 2005. The boxes connected by the dotted line show the annual mean measured temperature. The solid line is the 5-year mean. The 0 line is the 1961 to 1990 average temperature.

Problems with Fossil Fuel use

The Kyoto Protocol The world’s first coordinated response to the climate change problem has been the Kyoto Protocol, an international treaty seeking “stabilization of greenhouse gas concentrations in the atmosphere at a level that would prevent dangerous anthropogenic interference with the climate system.” The treaty was negotiated in Kyoto, Japan, in December 1997, then was ratified by nearly every nation on Earth before coming into force in February 2005. Kyoto regulates six major categories of greenhouse gases, including CO2. The 36 industrialized countries that signed the agreement are obliged to collectively reduce their greenhouse-gas emissions by 5.2% below 1990 levels by between 2008 and 2012. This value is 29% below what these nations’ emissions would likely be without the reductions. Emissions reductions are by an internationally agreed upon cap-and-trade program. Each participating nation’s greenhouse-gas-emissions cap is set by United Nations Framework Convention on Climate Change (UNFCCC) and is based on the nation’s size and the state of its economy. Requirements are for an 8% reduction for the European Union, 6% for Japan, 0% for Russia, and a permitted increase of 8% for Iceland. Participating nations are then allowed to trade emissions credits amongst themselves. A country

that will exceed its limit can buy credits from a country that will not use all of its credits. The trading scheme provides financial incentive for countries to meet and even exceed their targets. Developing countries are exempt from emissions reductions at this time because they have so far contributed a very small share of emissions, their per-capita emissions are still relatively low, and because they have great social needs. Countries are also rewarded credits for protecting forests and other CO2 sinks. So far, the Kyoto Protocol has not been a great success. The United States, which would have a cap of 7% below 1990 emissions, refused to sign because U.S. politicians feared that emissions restrictions would slow down the nation’s economic growth. The nation engages in voluntary cutbacks, but by 2005, the greenhouse gas emissions of the United States were 19% over what it would have been if it adhered to its Kyoto limits (although emissions fell by 1.3% in 2006 probably because of heightened fuel costs). Major greenhouse-gas emitter China is exempt from emissions reductions because it is a developing nation. In addition, many of the treaty’s participants are not on target to meet their emissions goals. (continues)

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(continued)

Climate scientists say that the Kyoto Protocol does not go nearly far enough. Even if all developed nations participated, the treaty would only result in a reduction in global temperature of between 0.04°F and 0.5°F (0.02°C and 0.28°C) by the year 2050. One climate

model suggests that reductions of more than 40 times those required by Kyoto would be needed to prevent atmospheric CO2 concentrations from doubling during this century. Defenders of the treaty say that its value lies in how it helps set the stage for larger emissions limits in the future.

World CO2 emissions in 1990, 2010, and 2030 with and without adherence to the Kyoto Protocol. In both cases, carbon emissions rise, with just a slightly smaller decrease when Kyoto is adhered to. This argues for the need for greater emissions reductions by more nations.


world’s total in 2002) partly because it has the world’s largest economy, but also because the nation is only half as efficient in using energy as the Western European countries. Other large greenhouse-gas emit- ters are the nations of the European Union (this value changes since nations are always being added to the EU), China (15%), and India (5%). Emissions from industrial nations are rising at 1.2% a year, versus 2.8% for developing nations. China is projected to pass the United States as the world’s largest greenhouse-gas emitter by 2009 (by some estimates, this had already occurred in 2007) because of China’s reliance on coal and its inefficient energy use. The growth in greenhouse-gas emissions from the developing nations means that every 10% reduction that the industrial world makes in its emissions is made up for by less than four years of growth in the developing world. While no single event can be attributed unequivocally to global warming, the sum of all of the changes the world is witnessing is a strong indicator that global warming is already occurring. These changes agree in type and magnitude with the models created by climate scientists. Some of these changes are

Changing weather patterns 

Wet regions are becoming wetter and dry regions are becoming drier. The United States has weathered a 20% increase in blizzards and heavy rain storms since 1900. The total amount of winter precipitation is up 10%. By contrast, dry areas have more than doubled in size since the 1970s.  Extreme weather—heat waves, drought, and floods—is increasing in frequency and duration. The hottest summer in Europe since 1500 occurred in 2003, resulting in 26,000 deaths. About 30% of the world’s lands are now stricken by drought, double the area of the 1970s. In 2005, the Amazon basin suffered the worst drought on record.

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Waves and storm surge pound a beach during a 1978 hurricane. (NOAA/Historic NWS Collection)

• There

were 10 times as many catastrophic floods between 1990 and 2000 than in an average decade between 1950 and 1985. In 2004, 150 million people were affected by floods, up from 7 million in the 1960s.  Hurricanes, violent ocean storms that sometimes bring strong winds and rain on land, draw their power from the heat energy arising from tropical waters. Hurricanes have increased in duration and intensity by about 50% since the 1970s. The number of category 4 and 5 hurricanes jumped from 50 per five years during the 1970s to 90 per five years since 1995. The North Atlantic experienced an increase from 16 strong hurricanes between 1975 and 1989 to 26 between 1990 and 2004.


Changes in ice, snow, and water 

The Greenland and Antarctic ice sheets are melting and portions of them are collapsing.  The summer sea-ice cover over the Arctic Ocean has decreased 20% since 1979. Sea-ice extent hit a record low in 2007.  Mountain glaciers all around the world are retreating: The Andes Mountains of South America are losing their glaciers at a rate of 328 feet (100 m) per decade. Mount Kilimanjaro’s glacier in Africa is predicted to be gone by 2015.  The ice on large lakes and rivers in the mid- and high latitudes (nearer the poles) now freezes nine days later in the season and breaks up 10 days earlier. The ice is also thinner and less extensive than in the past.

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Arctic summertime sea-ice extent in 2005 and 2006 compared with the average from 1979 to 2000. The past several years have seen a large decrease in sea ice even relative to that recent time period, the most recent for which there is satellite data, with 2005 being the record low as of November 2006.

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humans and the natural environment 

Winter and spring snow packs are smaller and snow melts earlier, resulting in rivers with lower volume. In addition, their peak flows are coming earlier in the spring.  The temperature has risen in Northern Hemisphere lakes and rivers by about 0.3 to 3.6°F (0.2 to 2°C) since the 1960s.  Global surface ocean temperatures have risen 0.9°F (0.5°C) over the past four to five decades.  Sea level rose 8 inches (20 cm) in the past century, with an average rate of 0.1 inches (0.3 cm) per year between 1993 and 2005.

Changes in organisms 

The results for 1,700 Northern Hemisphere species studied are Migrating species of birds and insects moved northward 3.9 miles (6.1 km) per decade. Spring life-cycle events of some animals started an average of 2.5 days earlier per 1.8°F (1°C) temperature rise.  In the southwestern United States, trees already weakened by temperature increases and a multi-year drought have been killed by a piñon bark beetle (Ips confuses) infestation. Bark beetles are killing trees in other forests in the western United States and Canada.  North Atlantic plankton and fish have moved northward 10° in 40 years.  Coral reefs are bleaching, destroying the ability of the coral to produce food. As of 2004, 20% of the world’s coral reefs were severely damaged from all causes, and 24% were on the brink of serious ecosystem collapse.

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Changes for humans 

Flooding due to storms superimposed on rising sea level is driving residents of some low-lying Pacific Island nations from their homes.

Problems with Fossil Fuel Use 

Sea ice arrives later and leaves earlier each year, shorten- ing the winter hunting season for the Arctic Inuit. Summer hunters are cut off from the migrating caribou herds by melting ice.  Alaskan fishing villages are eroding: In the summer of 2006, the people of Shishmaref voted to move their village inland at a projected cost of $100 million.  Disease pathogens are spreading to areas that were once too cold for them to thrive. Illnesses such as tuberculosis and influenza are re-emerging as major threats. New threats, such as West Nile virus and Lyme disease, have developed.

A Warmer Future Climate scientists predict future climate using sophisticated models run on supercomputers. Climate models have many uncertainties, most importantly the rate of future greenhouse-gas emissions: Will emissions increase at the same rate they have for the past decade, increase at an even higher rate due to lifestyle improvements, or decrease due to imposed emissions limits? If greenhouse-gas emissions continue as they are—what scientists call the business-as-usual model—CO2 will double from its preindustrial value of 280 ppm to 560 ppm by about 2080, and average global temperature will rise around 5°F (2.8°C). Temperatures will not increase uniformly: The Northern Hemisphere will warm more than the Southern, and the polar regions will warm much more than equator. A temperature increase of that magnitude is predicted to have many negative consequences: 

Agricultural yields may increase at higher latitudes, but they will be reduced at lower latitudes. The North American bread basket will move from the midwestern United States into Canada. The need for irrigation will increase, and regions that cannot supply enough water for crops, like subSaharan Africa, will experience famine.

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The possible range in temperature from various models projected to the end of this century is shown relative to the temperature variations of the past 1,000 years, putting the risks of the future in perspective.



Extreme weather—intense rainstorms, flooding, heat waves, droughts, and violent storms—will become more common. Commenting on the 2003 European heat wave, Prime Min- ister Tony Blair of Great Britain said in 2004: “It is calculated that such a summer is a one in about 800 year event. On the latest modeling, climate change means that as soon






 

as the 2040s at least one year in two is likely to be even warmer than 2003.” Droughts will make marginal regions—including the western United States, northern China, and Southern Africa— uninhabitable without major inputs of water. Sea surface temperatures will rise, bringing about more El Niño events, the replacement of cold water with warm water off of western South America, and possibly the increased frequency and severity of hurricanes. Arid and semi-arid regions will experience more droughts, resulting in increased stress on water and food supplies. About one-third of species will be lost from their current ranges.

The 1995 Chicago heat wave. (© Gary Braasch from the book Earth Under Fire: How Global Warming Is Changing the World, University of California Press, 2007.)

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humans and the natural environment  







Disease pathogens and parasites, such as malaria, will spread into areas that have typically been too cold. Coral reefs will die as they lose their ability to produce food. Coral reefs are nurseries for many types of fish, and commercial fisheries may suffer. Ocean acidification will decrease the ability of marine organisms to make shells and cause existing shells to dissolve. Acidification will decrease plankton population, which could initiate a collapse of ocean ecosystems. Rising sea level could make more than 350,000 (25%) of the houses within 500 feet (150 m) of the United States coast uninhabitable by 2060. By 2080, hundreds of millions of people worldwide may be forced to abandon lowlying coastal areas. Sea level could rise by 2.1 feet (65 cm) by 2100. Warmer temperatures will increase the range of plant diseases and parasites, which will affect forests and crop plants.

The impacts of climate change will strike developing nations earlier and harder than developed nations due partly to their location. Poor overpopulated nations will not have the financial resources they need to adapt to changes. According to the International Panel on Climate Change (IPCC), by 2100, 30 times more people will be displaced, 12 times as much area will be inundated, and flood protection for coastal regions will cost three times the amount of money for developing nations as it will for developed nations. The wealthier nations of the world may come to the aid of the poorer ones for a time, but the costs may eventually become too great. In developed countries, the costs of climate change may be masked by other advances, such as increasing the amount of land that is irrigated. Private insurance will pay for some of the damage from extreme climate events for a time. In the long run, the costs of dealing with climate change will be very high. Estimates are that the cost of damage could reach $150 billion each year in the next 10 years.


Humans are extremely adaptable, but the changes that climate scientists foresee will be far greater than anything experienced during the course of human history. They say that it is unlikely that human civilization will be able to survive unaltered. Even a small decrease in global food production or water availability could lead to famine, water scarcity, or political unrest—for several billion people.

Wrap-up Without energy, world commerce would collapse. But rampant fossilfuel use is having a tremendous negative environmental impact on the planet. The greatest problem is global warming, the consequences of which are becoming more apparent as ice melts, organisms change their habits, and island nations become uninhabitable. A future with rising greenhouse-gas emissions will likely be a future of rising seas, species extinctions, and disruptions of human civilization. Some of the suggestions that are being made by climate scientists for reducing atmospheric greenhouse-gas concentrations are presented in the next chapter.

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9 The Energy Future

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limate scientists urge the taking of several steps to mitigate global warming: Improve energy efficiency, transform energy technology from carbon-based fuels to alternative energy sources, and develop carbon capture and sequestration, among other ideas. This chapter also discusses how sustainable energy sources— solar, wind, geothermal, tidal, and wave—are renewable and do not produce greenhouse gases.

FuTuRe eneRgy needs and emissions Demand for energy, if it continues unabated, is projected to increase by 60% between 2006 and 2030, with a near doubling (an increase of 100%) by 2050, according to British Petroleum (BP) chief scientist Steven E. Koonin. China’s demand is expected to double over 15 years, and India’s may double in 30 years. At this time, it appears that the increase in energy will mostly be supplied by fossil fuels, much of it from coal. 100

The Energy Future

Energy use and projected energy use by type, 1980 to 2030. Although the use of renewable energy sources is forecast to increase in the coming decades, fossil-fuel use is expected to increase much more.

Coal-fired power plants are being built rapidly, especially in China, where a new one opens every week to 10 days. Coal power from new plants will increase by 221 gigawatts (GW) between 2003 and the end of the decade, with increases in the next two decades projected at 500 GW and 670 GW. For comparison, the total power in the United States in 2006 was 800 GW, about half of it from coal. When he presented these data at the State of the Planet 06 conference, author Joseph Romm stated, “The coal plants built between 2003 and 2030 . . . will emit over their lifetime as much carbon dioxide as every piece of coal that has been burned since the dawn of the industrial revolution. This is unsustainable development.”

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Along with rising energy needs, there must be a reduction in g reenhouse-gas emissions—and all nations will need to be involved. Climate scientists say that the developed nations should lead the way because they are responsible for most of the excess CO2 that is currently in the atmosphere. They have also outlined a series of steps toward reducing greenhouse-gas emissions in developed and developing nations. Although these researchers do not all agree on the details, they do agree that something must be done very soon. Some of their ideas are discussed below.

Step One: Improve Energy Efficiency The easiest and quickest way to reduce greenhouse-gas emissions is to promote conservation and radically improve energy efficiency. Financial motivation generally works best to encourage conservation. In fact, rising energy prices have already caused industries to make improvements in energy efficiency. Today, it takes only 60% as much energy to produce steel and paper as it took in the mid-1970s. A cut of 25% in energy usage has taken place in petroleum refining, aluminum refining, and cement production. To augment the gains being made by rising energy prices, many climate scientists favor placing a surcharge on the energy sources that release CO2. This is known as a carbon tax, which would be added to the price of gas or onto an electric bill. Because of these additional costs, consumers would then be motivated to drive less, purchase more fuel-efficient vehicles and energy-efficient appliances, and keep the heat turned down during the winter, and air conditioning down during the summer. A subsequent increase in consumer demand for energyefficient cars and appliances would give industry an incentive to create and supply them. The money collected from the carbon tax could then be used for research on alternative fuels and to develop mass transit systems, along with many other energy-saving possibilities. Since transportation is such a large part of the energy budget, improvements in fuel efficiency in vehicles is extremely important. The U.S. government could make a tremendous impact by increasing the fuel economy standards of its enormous vehicle fleet from 22 to

The Energy Future

40 miles per gallon (9.3 to 17 km per liter), a policy that has been discussed but has not yet been implemented. Changing government fuel economy standards worked during the energy crises of the 1970s, when automakers nearly doubled the average efficiency of automobiles. Subsequently, global growth of CO2 fell from 4% per year to between 1% and 2%. Government mandates would ensure that new technologies were used for increased energy efficiency. Hybrid vehicle technology, for example, can be used to reduce gas consumption or to improve accel- eration in larger vehicles. Hybrid vehicles, which can get nearly 50 mpg (21 km per liter), make use of the energy that is usually lost during braking by putting it through an electric motor and into a rechargeable battery. To reduce the need for gasoline further, hybrid cars are being developed that can be plugged into an electrical outlet overnight. A plug-in hybrid car would be able to run its first 20 miles (32 km) on electricity, which is as much as many people travel in a day. Cars can be made more fuel efficient by being smaller and constructed of lighter-weight materials. Reducing the speed limit from the current 65 miles per hour (105 kph) back to 55 mph (89 kph), as it was during the energy crisis of the 1970s, would increase fuel efficiency by 15%. Governments can also mandate that homes and businesses be more energy efficient. Weatherization and programmable thermostats help a home or business use less energy, as does keeping the thermostat up in the summer (80°F, or 23°C) and down in the winter (65°F, or 18°C). Using appliances with the Energy Star designation, which is awarded by the Environmental Protection Agency (EPA) to energy-efficient appliances, also reduces energy use. Commercial spaces can lower energy consumption by not overlighting and by using fluorescent lighting, which is about four times as efficient as incandescent lighting. Developing countries, such as China and India, produce much more CO2 per unit of their gross national product (GNP) than the developed countries. In other words, they are very inefficient at using energy. Therefore, with technological assistance they can easily increase their efficiency and lower their CO2 emissions. Yet, improvements in energy efficiency cannot make up for the enormous increases in energy use

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that are taking place in these nations. Since coal will continue to be important to developed and developing nations, great improvements can be made if coal-fired power plants are made cleaner. Gasification (or IGCC—for integrated gasification combined cycles) is a promising technology that has not yet been used in a fullscale power plant. In gasification, coal is heated to about 2,500°F (1,400°C) under pressure to produce syngas, a clean, energy-rich flammable gas. Syngas is combusted in a turbine that drives a generator; the waste heat powers a second, steam-powered generator. Syngas can also be liquefied and burned like gasoline. An IGCC plant is more efficient and produces far fewer emissions than a traditional coal-fired power plant. Emissions of most air pollutants from this type of facility are reduced about 80% and greenhousegas emissions, particularly of CO2, are lower. Gasification has other positive features: Because the coal is cleaned during combustion, coal that is too dirty for a traditional power plant becomes usable. Gasification plants do not need expensive pollutionreducing scrubbers like traditional coal-fired plants. Gasification, however, consumes about 10% to 40% more energy, making the process expensive. Gasification plants cost 15% to 50% more to build and 20% to 30% more to run than traditional coal-fired plants. Due to these additional costs, clean coal plants are not being built at this time and conversions from traditional plants will not become widespread until industry is given financial incentives or emissions caps. The processes of carbon capture and carbon sequestration capture CO2 before it is emitted into the atmosphere and sequester it in a location where it can be stored for thousands of years. CO2 is easily captured from gasification plants, so emissions from these plants can be reduced by 80% to 90%. CO2 can also be captured from natural gas and biofuel plants. Once the CO2 is captured, it can be transported by pipelines or by ship to a storage site, such as an impermeable salt layer or coal seam. Reports by the Intergovernmental Panel on Climate Change (IPCC) suggest that sites could be developed that would trap CO2 for millions of year with less than 1% of it leaking over a period of 1,000 years. Several sequestration projects are currently underway:

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Norway is injecting CO2 from natural gas into a salt formation in the North Sea, while CO2 from a coal gasification plant in North Dakota is being used to enhance oil recovery in a reservoir in Canada. BP is involved in a project in Algeria that will store 17 million tons (15 million metric tons) of CO2.

Step Two: Transform Energy Technology Most climate scientists say that to substantially reduce greenhousegas emissions, society must make a massive change in the way energy is produced and used by the middle of the twenty-first century. This will require a transformation from fossil fuels to sustainable energy sources that create zero- or low-carbon emissions. While progress is being made to develop and grow renewable energy sources, the current growth rate in that sector is only 3.3% per year. Financial incentives could encourage research into less expensive and more efficient forms of renewable energy. Hydropower harnesses the energy of falling water, which spins the blades of a turbine to produce electricity. Hydroelectric energy is renewable as well as free of pollutants and greenhouse gases. Hydro- power already produces about 24% of the world’s electricity, but rivers in developed countries are almost fully utilized, which limits further development. Damming of rivers, however, will continue to take place in some developing countries. Solar energy technology continues to improve. Photovoltaic cells, also known as solar cells, convert sunlight directly into electricity in a process that is renewable and produces no pollutants or greenhouse gases. Solar cells arranged in solar panels on rooftops can provide a building’s energy. Producing large amounts of electricity requires assembling huge arrays of solar cells into panels, parabolic troughs, thermal dishes, or power towers. The potential for solar power is enormous, particularly in sunny locations like the southwestern United States. Wind energy also has enormous potential: It is renewable, nonpolluting, produces no greenhouse gases, and is widely available. Wind energy is also becoming less expensive. The price of electricity from

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wind now costs only 20% what it did 20 years ago. To create usable power, the wind turns turbine blades that a generator transfers into usable electrical current. Small wind turbines can be placed individually in open areas, but the large-scale use of wind energy requires a wind farm. Estimates are that wind could supply 40 times the current demand for electricity, a figure amounting to about five times the global consumption of all power. Although wind generated only about 1% of global power usage in 2006, that amount represents more than a four-fold increase between 1999 and 2006, and as demand increases, the cost will go down. Geothermal energy harnesses the energy contained in hot rock below Earth’s surface. With this process, hot water flows directly from hot springs, or cold water is heated when it is pumped into a region of hot rock. The steam produced is then used to generate electricity. Geothermal energy is renewable, nonpolluting, and does not emit greenhouse gases. The U.S. Department of Energy estimates that geothermal sources could provide up to 30 times the annual energy currently used in the United States. Only Iceland currently uses geothermal energy on a large scale. Research is ongoing on a more advanced geothermal technique called Enhanced Geothermal Systems (EGS). In this process, bore- holes are drilled into rock to a depth of about 6 miles (10 km), a depth routinely drilled by the oil industry. In 2006, the Massachusetts Institute of Technology (MIT) reported that, with improved technology, EGS has the potential to supply the world’s total energy needs for the next several thousand years. The steam from the deep holes could be used in an existing coal, oil, or nuclear power plants. The oceans are alive with energy. Tidal energy exploits the rise and fall of the tides. Water is trapped behind a dam-like structure at high tide and released at low tide when the energy of the falling water is collected. Although a few tidal energy plants have been built, the structures are large, expensive, and restrict water movement, potentially causing environmental damage. Ocean waves can also be harnessed for power, although only a few experimental plants are operating so far.

The Energy Future

Ocean thermal energy conversion exploits the difference in temperature between the warm surface waters and the cold deep waters. Heat from the surface waters is used to vaporize a fluid with a low boiling point, like ammonia. The pressurized vapor turns a generator to produce electricity. Cold seawater pumped up from below the surface helps recondense the vapor so the ammonia is conserved. Experiments into this technique have been successful, but the technology has not been pursued because it has low efficiency and building and maintain- ing the plants would be complex and expensive. Categorizing nuclear energy as a sustainable energy source is controversial. Many people oppose nuclear power plants because they have a history of accidents and the transport of nuclear materials exposes many people to potentially harmful radiation. In addition, the waste generated is radioactive and must be safely stored for more than 10,000 years. Proponents say that the dangers have lessened as technologies have improved and that the damage to Earth being done by fossil fuels makes nuclear power more attractive. Nuclear fission plants, the only nuclear plants that are currently in operation, use enriched uranium as their energy source. Current estimates are that if fossil fuels were replaced by nuclear fission, there would only be enough uranium for about 6 to 30 years, although uranium can theo- retically be collected from seawater. Research is ongoing into breeder reactors, in which the byproducts of nuclear fission are made to breed new fuel, and nuclear fusion, which would produce unlimited clean power if it could ever be harnessed. Ethanol is liquid biofuel produced from plant material that can be burned in place of gasoline. Ethanol is typically produced from plant sugar, such as the sugar produced by corn. Cellulosic ethanol is made from crop wastes, like plant fiber or cellulose from corn stalks. Cellulosic ethanol could supply about 25% of the energy needed for transportation in the United States while creating about 85% less greenhouse gases than typical gasoline. Biodiesel is a liquid fuel that can be made from fats such as those used cooking oil, animal guts, used tires, sewage, and plastic bottles. Although biofuels are not pollutant free, the CO2 was taken from the environment recently so

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its addition back into the atmosphere has no net effect (unlike fossil fuels, which emit CO2 that has been stored for millennia and so add to the burden on the atmosphere). Biofuels are currently added to some gasoline sold in the United States. One of these fuels is E85, which consists of 85% ethanol and 15% gasoline. Ethanol fuel, however, is as much as 25% less efficient than gasoline per gallon. Biofuels have their limits as an alternative fuel source. Cellulosic ethanol is limited by the low amounts of suitable agricultural waste when compared with the amount of fossil fuels used each year. Grow- ing crops to produce biofuels is an extremely inefficient use of energy. Because fossil fuels are used extensively in pesticides, fertilizers, and for machines, there is little or no energy gained from biofuels created from crops like soybeans or rapeseed. Ethanol produced from corn on a large scale would likely increase food prices, because corn is a basic ingredient throughout much of the food industry in products from animal feed to corn syrup. A 2005 paper by David A. Pimentel of Cornell University and Tad W. Patzek of the University of California, Berkeley, stated that the corn-to-ethanol process powered by fossil fuels consumes 29% more energy than it produces. Other scientists say that biofuels provide a reasonable alternative to fossil fuels if the right crops are used and ethanol-producing plants become more efficient. Algae, for example, contain much more usable oil than land-based crops and could be grown with agricultural and other wastes. At this time, however, research into algae biofuel is in the early stages. Fuel cell use is in its infancy, but is entering a rapid growth phase, with about a seventeen-fold increase in expenditures expected between 2004 and 2014. Fuel cells may someday be used in motor vehicles, but will not be ready for mass production for some time. Fuel cells are extremely efficient at harnessing the energy released when hydrogen and oxygen are converted into water. This makes them the basis of what is known as the hydrogen economy. Fuel-cell technology is promising because it is incredibly efficient when pure hydrogen is used, the oxygen needed for hydrogen-oxygen fuel cells is

The Energy Future

widely available in the air, and hydrogen fuel cells produce CO2 but no other emissions. Unfortunately, there are many problems with fuel-cell technology. Hydrogen does not exist in vast reservoirs: It must be created. Most of the current generation of fuel cells runs on the hydrogen found in natural gas, which is needed for other important uses. Fuel cells using natural gas require a large amount of energy, have high waste heat and emissions, and produce more CO2 than burning the fossil fuels directly. Joseph Romm, the author of The Hype about Hydrogen, is not enthusiastic about the hydrogen economy. At the State of the Planet 06 conference he said, “The short answer for why you can forget hydrogen is [because] hydrogen is just an energy carrier: You have to make it from something.” Romm goes on to say that if hydrogen is made from natural gas or renewable electricity sources, these resources would no longer be available to displace coal use, so there is not a net improvement for the environment. He urges automobile manufacturers to “focus on fuel economy for the next two decades, and then on more plausible alternative fuels than hydrogen.” No one alternative energy source can meet America’s demand for energy now, or in the future. To do that between now and 2050, according to Thomas Homer-Dixon in a 2005 New York Times edito- rial, would require 

1,200 new nuclear power plants. 4,000 square miles (10,000 sq. km) of photovoltaic panels at a cost of half the country’s gross domestic product (GDP).  230,000 tons (210,000 metric tons) of hydrogen to put hydrogen fuel cells in all current cars and trucks and double the current electricity to electrolyze enough water to produce the hydrogen. 

It seems clear that what will be needed to replace fossil fuels will be a combination of renewable power sources and a modernization of currently used power sources to make them cleaner.

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Wrap-up Climate scientists suggest, and some even insist, that now is the time to make the changes that will reduce greenhouse-gas emissions and slow the climate changes that are already under way. The first step would be to place a carbon tax on CO2 emissions to reflect the true costs of burning fossil fuels. This would encourage an increase in energy efficiency and put a large amount of money into research and development of alternative fuels and alternative technologies for existing fuels. Then, energy from renewable sources would become cost-competitive and a conversion to zero- or low-carbon emissions fuels would be able to take place. In energy, as in all resource use, many people are using the resources and producing wastes. As Chris Rapley, director of the Brit- ish Antarctic Survey, told the British Broadcasting Corporation (BBC), “Although reducing human emissions to the atmosphere is undoubtedly of critical importance, as are any and all measures to reduce the human environmental ‘footprint,’ the truth is that the contribution of each individual cannot be reduced to zero. Only the lack of the individual can bring the footprint down to nothing.”

PART FOUR

LIVING RESOURCES

10 Growing Food

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he growth of human population and agriculture has gone hand- in-hand: Each time agricultural techniques advance, the human population grows. So far, as will be discussed in this chapter, this mutual reinforcement has continued, even though a significant number of the world’s people live in dire poverty.

SubSiStence FarMing Anthropologists think that without agriculture, the carrying capacity of humans on Earth would be around 10 million people. That population number was reached about 10,000 years ago when humans were hunters and gatherers. Agricultural development has allowed the planet to support 660 times that number, and will likely support even more. From the time agriculture was born, each major advance in farming techniques has increased the number of people one farmer could feed, with the result that the population has grown.

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People have been clearing wild lands for farms since the beginning of agriculture. Lands that are suitable for farming are referred to as arable: They have nutrient-rich soil and available water. Among the best places to farm are floodplains, where annual floods bring nutrients to the soil. Filled wetlands and cleared temperate forest are also good locations for farms. Soil is an extremely important natural resource for farmers because plants cannot grow without the proper soils. Productive soils trap nutrients and water and provide the stability plants need to grow. The top layer is good topsoil, which contains broken up and partially decomposed organic material, weathered bits of rock, and many living creatures, such as bacteria, fungi, algae, protozoa, insects, worms, nematodes, and mites. Most farming has been, and continues to be, subsistence farming. Subsistence farmers must work the land carefully and need some good luck or they will lose their crops and their food for that season. To be sucessful, subsistence farmers must take steps to protect their soil and its nutrients with practices such as rotating crops, planting polycultures (which are multiple species growing together), and replacing soil nutrients—elements that are essential to plants and animals for living and growth—with natural fertilizers, like manure and crop wastes. To control the damage done by insects and weeds, subsistence farmers use inexpensive methods like being careful of where crops are grown and materials like tobacco extract as natural pesticides and herbicides. Water comes from rain or from local irrigation: If the rains fail to come or the stream runs dry, the year’s crops will dry out. When conditions are good, a farmer might be able to sell some of the harvest to raise money for supplies. When conditions are bad, the farmer’s family may go hungry. Long before the study of genetics, agriculturalists in the Fertile Crescent of Mesopotamia 10,000 years ago discovered selective breeding. The concept of selective breeding is simple: By breeding only plants or animals with certain desired traits, most of their subsequent generations of offspring will also have only those desired traits. This process can now be described in terms of genetics. Selective

Growing Food

breeding changes the frequency of genes in a population of an organism so that future generations are more likely to have the favored genes and therefore the desired traits. Genes are the units of heredity that make up an organism’s deoxyribonucleic acid (DNA). Genes are passed from parent to offspring: Their expression determines the traits the offspring will have. (Genetic traits are discrete, not blended. For example, a red-flowering pea plant and a white-flowering pea plant will have offspring with red or white flowers, not pink.) When a farmer selectively breeds an organism, the genes for desired traits will remain in the population, while the genes for the undesired traits will be reduced in frequency or bred out entirely. Farmers have traditionally bred crops to improve yield, disease resistance, drought tolerance, ease of harvest, and sometimes improved taste and nutrition. Worldwide, thousands of plants have been domesticated for crops, and farmers in a single region may have hundreds of plant species available for planting. Animals have been bred to produce the maximum amount of meat, give birth to more and healthier young, or for farm work. Although about 42% of the world’s labor force is engaged in agriculture, these workers produce only about 4% of the world’s gross domestic product (GDP). This number is low because subsistence farmers raise only enough food to meet their family’s needs. At this time, more than 70% of the world’s poor are subsistence farmers in rural communities. Some 800 million poor people try to farm with insufficient water and poor soils, and are unable to grow enough food to stay healthy, or for their children to develop normally.

Modern Farming Agricultural advances in the developed nations and some developing ones over the past two centuries greatly increased farm productivity. Even greater advances in productivity were made after World War II as the result of the Green Revolution. The techniques developed during this time greatly increased the yield a farmer could get out of each acre of farmland. As a result, cropland has increased only 12% in the past

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40 years, but grain harvests have doubled. The advances of the Green Revolution have been due to changes in the strains of grain that are grown, increased mechanization and irrigation, and the widespread use of artificial fertilizers and chemical pesticides. The father of the Green Revolution was Norman Borlaug (1914–), who received the Nobel Peace Prize for his work in 1970. Borlaug spent years selectively breeding a high-yield, disease-resistant variety of wheat. Borlaug did his early work in Mexico, where his wheat strain increased the country’s crop six-fold between 1944 and 1963 and made the nation a grain exporter. Borlaug next focused on India and Pakistan, where his wheat strain allowed food production to increase faster than the nations’ booming populations. Between 1968 and 2006, India’s wheat production increased by 730%. Despite these accom- plishments, however, selective breeding has limitations. The process is time-consuming, since traits must be selected for over many generations. Also, a trait can only be selected for if it is present in at least one member of that species. Genetic engineering is a quicker and more flexible way to introduce a trait into a species. In genetic engineering, also called genetic modification (GM), a gene coding for a desired trait is cut out of the DNA of an organism from one species and spliced into the DNA of an organism from another species. A gene can be added to a crop plant to make it resistant to an herbicide. Genetic engineering has now created herbicide- and insecticide-resistant canola, corn, cotton, and soybeans; disease-resistant sweet potatoes; iron-, iodine-, and vitamin-fortified “golden rice”; protein-enriched potatoes; lysineenriched maize for animal feed; and crops that can better tolerate low water, hot weather, high- salinity soils, and other environmental stresses. Because they can be grown in marginal environments and can be made more nutritious, GM crops can help stave off hunger in poor nations. Crops that are genetically engineered to repel insects need less pesticide use. GM crops are rapidly growing in popularity. The United States is the leader in growing them, but countries such as Argentina, Canada, China, Brazil, and India are joining the trend. In India, one area where

Growing Food

GM crops are planted expanded by more than 2.5 times from 1,930 square miles (5,000 sq. km) to 5,000 square miles (13,000 sq. km) just between 2004 and 2006. Subsistence farmers in other developing countries are beginning to use GM crops. In 2006, in the United States, 89% of soybeans, 83% of cotton, and 61% of maize were genetically modified. The Grocery Manufacturers of America estimate that 75% of all processed foods in the United States contain at least one GM ingredient. Nearly every aspect of agricultural work in developed countries is now done by machines, replacing domesticated animals and humans as the dominant labor source. Large tractors and plows work the land; self-propelled units spray fertilizers, pick crops, and bale hay; and trucks transport goods in and food out, among many other tasks. These machines are built and powered by natural resources, primarily metals, and fossil fuels. About 17% of the energy consumed annually in the United States is for agriculture. One acre (4,047 sq. m) of land farmed using modern techniques requires 50 or even 100 times the amount of fossil fuels as that same acre farmed with traditional methods. Modern farming also requires irrigation, which expands the amount of land that can be used for growing crops and allows farmers the ability to grow crops that are not otherwise well-suited for that particular environment. About 65% of the world’s freshwater is used for agriculture. The need for irrigation water has spurred the building of dams on many of the world’s large rivers. Dams also keep rivers from flooding (except in extreme instances), which protects the homes and businesses that have grown up in riverside communities but has stopped the supply of nutrients that once flowed onto the rivers’ floodplains. As a result, farmers must add more fertilizers to their crops. Modern farmers use enormous amounts of chemical fertilizers to add nutrients and some trace elements back into the soil. Soils are deficient in nutrients for several reasons: floodwaters no longer bring nutrients to floodplain soils, farming takes place on more marginal lands where the soils are nutrient-poor, and modern farming practices are hard on soils. Because fields consisting of a single crop plant are easier to grow and harvest than mixed-crop fields, farmers plant

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monocultures year after year, even though this practice strips the soil of its nutrients. This is one reason that modern high-yield crops also need more nutrients to grow. Chemical compounds such as ammonium nitrate and potassium sulfate are extremely effective fertilizers. These chemicals are the same as those found in explosives. Phosphates for fertilizers are mined from phosphate beds and chemically altered to a form that is more concentrated and soluble (in the forms of superphosphate, triple superphosphate, or ammonium phosphate). Nitrogen fertilizers are made from atmospheric nitrogen in a process that uses the gas methane, which is derived from fossil fuels. The past 50 years have seen a twenty-three-fold increase in fertilizer use globally, according to Ismail Serageldin, director of the Library of Alexandria in Egypt, who spoke at the State of the Planet 06 conference. In 1950, fewer than 50% of corn fields in the United States received any inorganic nitrogen, but now that number is above 99%. During that same time, less than 2% of the nitrogen applied to fields in China was from inorganic sources, but now that number is more than 75%. Modern farming also depends on chemical insecticides and herbicides to keep down unwanted pests and weeds. According to Serageldin, pesticide use has increased 53 times globally in 50 years. Chemical pesticides were first used in the early 1940s and became increasingly common in the years after World War II. Spray machines or small airplanes called crop dusters are used to spray these chemicals over the fields.

Modern Farming and Population Growth The Green Revolution has allowed food production to outpace population growth. Crop yields have increased astronomically. A farmer in the early twentieth century produced enough food for 2.5 people, but a farmer today can feed more than 130 people. In the United States, between 1900 and 2001, maize production increased from about 40 bushels per acre (2.5 tons per hectare) to about 150 bushels

Growing Food

Increases in wheat yields (the amount of wheat produced per unit area) between the years 1950 and 2004 were very high in nations that practiced Green Revolution agricultural techniques. Most dramatic was wheat yield in Mexico, which was an early beneficiary of the Green Revolution.

per acre (9.4 tons per hectare). Global wheat production went from less than 1 ton per hectare in 1900 to 2.5 tons per hectare in 1990. Farmers in France produce more than 8 tons per hectare of wheat using modern methods, but subsistence farmers without irrigation in Africa still produce less than 1 ton per hectare. Norman Borlaug has been credited with feeding an estimated 1 billion people who likely would otherwise have gone hungry. It has been estimated that 40% of the people alive today owe their lives to ammonium fertilizers. Borlaug maintains that if pre-Green Revolu- tion agricultural techniques were used, either world population would

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be smaller or much more forest land would be converted to farmland. Some experts contend that high-yield grain has saved 100 million acres (400,000 sq. km), more than 13% of the total area, of India.

Wrap-up Modern farming has vastly increased the carrying capacity of Earth for humans. Without the Green Revolution, it is extremely unlikely that the human population would be as high as it is today. Yet, despite the obvious successes of the Green Revolution, many of the planet’s people have just enough food to survive. When conditions are bad—when there is a drought or a war—mass starvation strikes, particularly in sub-Saharan Africa where many inhabitants live on the edge. Besides the credit he gives to the Green Revolution for saving lives, Borlaug admits that the Green Revolution has not created a utopia and that keeping up with feeding people in a growing world is an ongoing battle.

11 Environmental Costs of Modern Agriculture

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o one disputes that the Green Revolution and other agricultural advances have been ineffective at allowing the human population to grow. But not everyone believes that these changes have been wise. Many people point to modern farming’s enormous environmental costs, costs that will someday have to be paid. Author Richard Manning said in Harper’s Magazine in 2004: “With the possible exception of the domestication of wheat, the green revolution is the worst thing that has ever happened to the planet.”

the coStS oF the green revolution Manning is concerned about what modern agriculture has done to society in both the developing and the developed nations. Modern commercial agriculture—with its large fields, intensive mechanization, and the need for large amounts of fertilizers, pesticides, and fossil fuels—places great demands on the Earth’s environment. Small family farmers cannot afford these financial outputs. If they are driven out of 121

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business, corporations or large plantation owners often take their place. In the United States, productivity is so high that only 2% of Americans are now farmers. The move away from a rural lifestyle is not so difficult to make in the developed nations where there are many other ways to make a living. In the developing nations, however, these displaced farmers flood into the cities looking for work, but only a few are able to find jobs. Most of these former farmers wind up living in poverty. There are many environmental costs to intensive agriculture. Mod- ern farming favors only a few high-yield crop types, and 60% of the plant-based foods grown today are rice, wheat, and corn. Other crop plants, and even the genes for traits that are not currently desired, are lost to genetic erosion. During the twentieth century, an estimated 75% of crop diversity was lost, according to the United Nations Food and Agriculture Organization (FAO). Currently, 70% of the world’s corn; 75% of rice in Asia; and 50% of wheat in Africa, Latin America, and Asia are modern varieties. Between 1950 and 2015, the number of varieties of wild rice found in India is expected to decline from 30,000 to 50. When crop varieties are lost, their genes are no longer available for plant breeders and genetic engineers. If a new insect pest or disease or a different set of environmental conditions, such as warmer temperatures, arises, a suitable gene for handling the situation may not be available. Eliminating backup plant strains and genes could be setting society up for a massive crop loss. Mechanization requires that farms grow monocultures. As monoculture farming spreads to developing nations, it causes other problems. Some of the crops that are not best for modern farm techniques are food plants that local people prefer and have eaten for centuries. Their diets are poorer for the loss of these foods. Traditional farms, especially in the tropics, have high species diversity. A single farm may include grains, root crops, vegetables, spices, medicinal plants, livestock, and trees for lumber, fruit, and firewood. Modern farms with only a small number of crop types are associated with low diversity of birds, insects, and soil organisms. Monocultures result in a loss of pollinators, especially bees, since there is no food

Environmental Costs of Modern Agriculture

for them. Losing pollinators is a deadly problem for the natural world and could be a problem for agriculture if that pollinator is needed for future crops. Farms growing monocultures need more pesticides since pests more easily grow out of control when they have an abundant, uninterrupted food supply and fewer natural enemies, like spiders, wasps, and beetles. Genetically modified (GM) foods generate other criticisms. Insects breed quickly, and, over generations, they can become resistant to pesticides. There is fear that they will also evolve to become immune to insecticide-resistant plants. In addition, companies that produce GM seeds protect their creations with patents, which restrict their availability to poor farmers, who may not be able to compete using their traditional crop plants. The biggest fear has been that a gene that was transferred into a GM crop will find its way into wild or non-GM species. That fear has already been realized, which is not surprising since pollen from GM plants can be carried by the wind to plants near and far. A 2002 study found genes transferred to maize in the United States had spread to traditional maize in Mexico. A 2004 study showed that conventional varieties of crops in the United States have been widely contaminated. For these reasons, GM foods are very rare in Europe and must adhere to strict labeling laws and regulations. Some African nations have also opposed GM crops and reject food aid that contains them. Fossil fuels have many uses in modern agriculture: for running machinery, manufacturing inorganic fertilizers and pesticides, pumping water, raising livestock, drying crops, and transporting goods. Between 1945 and 1994, there was a 300% increase in the amount of food grown, but a 400% increase in the amount of energy used for agriculture. Since 1994, even more energy has been used, but the increase in food production has been minimal. Increasing the amount of fossil fuel used to grow crops increases a nation’s oil deficit and brings about pollution and climate change. On average, every calorie of food produced requires one liter of water. Pastoralists, who subsist on raising animals, produce about 1,800 calories with 980 liters of water. American farmers require

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about 5,500 liters of water to produce about 3,200 calories of food because of the use of arid and semi-arid lands. The amount of water used for agriculture will likely need to increase by 14% in the next 20 years, as some farming regions will probably receive less moisture. Already, most rivers in developed nations and many in developing nations are dammed. Damming rivers has other implications for agriculture. Before the Aswan Dam was built, the springtime flooding of the Nile River brought in much-needed nutrients. Now farmers must add artificial fertilizers, which are sometimes too expensive. Subsis- tence farmers are then driven off their land by corporations that can afford the fertilizers. Irrigation is also causing the overuse of groundwater in many locations. Mining phosphates for fertilizers can be ecologically damaging. The tiny country of Nauru, for example, has become an environmental wasteland due to the intensive mining of its phosphate deposits. Chemical fertilizers produced from petroleum products take ancient energy from the Sun and use it to grow food. As Richard Manning said in Harper’s Magazine in 2004, Oil is annual primary productivity [the food energy created by producers] stored as hydrocarbons, a trust fund of sorts, built up over many thousands of years. On average, it takes 5.5 gallons (21 l) of fossil energy to restore a year’s worth of lost fertility to an acre of eroded land—in 1997 we burned through more than 400 years’ worth of ancient fossilized productivity, most of it from someplace else.

Since fossil fuels are limited in supply and are also politically vulnerable, having agriculture depend on them jeopardizes food security. Artificial fertilizers cause eutrophication in streams, lakes, and coastal ocean areas, as discussed in Chapter 5. Dead zones are found all around the coastal United States where major rivers flow into the sea. One of the largest and most persistent of them forms where the Mississippi River, which drains 41% of the land surface of the United States (including the rich farmland of the Midwest), flows into the


Gulf of Mexico. The dead zone forms when spring rains wash excess fertilizers into the river from fields, urban lawns, and golf courses, and it disappears in the autumn when storms mix the oxygen-poor waters with normal water. The fate of the dead zone is important since the Gulf provides 70% of the shrimp and two-thirds of the oysters harvested in the nation each year. Over the past two decades, the Gulf of Mexico dead zone has continually appeared earlier and become larger. The growth of the zone is not surprising, since triple the amount of fertilizer runs down the Mississippi now when compared with the period from the 1950s to the 1970s. During one of its worst years, 2002, the dead zone was more than 8,000 square miles (21,000 sq. km), slightly more than the size of New Jersey. In 2007, for the first time, a new dead zone formed off Texas to add to the Louisiana area. Researchers suggest that a 40% to 45% annual cutback in nitrogen use in the Mississippi River drainage area is necessary to decrease the dead zone to 3,000 square miles (5,000 sq. km). Nutrient runoff could be reduced by planting crops that cover the ground year round or by better controlling drainage. Pesticide use has also increased tremendously. The U.S. Envi- ronmental Protection Agency (EPA) estimates that 2.2 million tons (2 billion kg) of pesticides are applied to crops in the United States and 11 million tons (10 billion kg) are used around the world each year. Pesticides do not discriminate: They destroy not only pests, but also beneficial insects, fungi, and the predators that are the pests’ natural enemies. Pest species often evolve resistance to pesticides so that increasing amounts of pesticides must be applied, and new toxic chemicals must be developed. Increasing pesticide use is hazardous for human health, as discussed in Chapter 5. In many developing countries, environmental regulations are lax, and chemicals that have been banned in developed countries continue to be used. Eighty percent of human deaths from pesticides take place in the developing world. Besides harming farmers and their families, these chemicals enter and harm nearby ecosystems.

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Soil Degradation Intensive agriculture also causes soil degradation. Soils are so depleted in some locations that productivity is decreasing. In other locations, the land is too degraded to grow food at all. Excess nitrogen from fertilizers may become part of a chemical reaction that produces acids in the soils, known as acidification. Soils may also become acidic from acid rain or acid stream water. In arid regions, water evaporates from reservoirs and canals, leaving behind salts. If this brackish water is used to irrigate crops, the salts collect in the soil. If the cropland is poorly drained, enough salts collect to cause salinization of the farmland. The salts keep plants from absorbing soil moisture so they cannot grow, so eventually the farmland becomes unusable. Salinization damage can be prevented by flushing the soils with large amounts of nonsaline water, but that is not always available. Estimates are that already about 20% of the total irrigated agricultural land on Earth, about 170,000 square miles (450,000 sq. km), has been damaged by salinization. Each year, another 5,800 square miles (15,000 sq. km) of arable land become too saline for use, leading to a loss of about $11 billion annually in agricultural production. Soils can assimilate small amounts of contamination, but larger amounts damage the soil so that it is no longer productive. Slash-and-burn agriculture is a major cause of soil degradation. With this practice, peasant farmers clear tropical rain forest land by slashing down trees at the forest edge and then burning the unusable scrub. In rain forests, the nutrients are all found in the living plants, while the soils are nutrient poor. When the forest plants are cleared or burned, the nutrients are lost. After a few years of farming, this soil becomes infertile and cannot grow food. The farmer next grazes cattle on the land, a practice that tramps down the soil and leaves behind a bricklike surface layer. Once the old land becomes unusable, the farmer must slash-and-burn a new plot for crops. Large plantations are more successful at growing crops on former rain forest land because plantation owners (who are often corporations) can afford fertilizer to keep the soil fertile.


Soils that are damaged or intensively farmed are more vulnerable to erosion. Plowing loosens the earth and monoculture farming leaves it exposed to rain, wind, and gravity for part of the year. When the nutrient-rich topsoil erodes, it makes the land less valuable for agriculture or for ecosystems. Farmland soils erode at between 10 and 40 times the rate that soils form. In the world’s worst locations, soil is lost at a rate of 25 tons per acre (48 metric tons per hectare) per year. If every location lost soil at that rate, the entire world’s topsoil would be eroded away in 150 years. Since the arrival of Europeans, the United States has lost about one-third of its topsoil: The Midwestern breadbasket has lost that much in just 100 years. Artificial fertilizers must be added to make up for losses of soil nutrients, or the land becomes less productive. About half of the topsoil of Iowa has been eroded away in the past

Tree skeleton at Dead Vlei, near Sossusvlei, Namibia. In the background, more tree skeletons and a tall sand dune. (Anchesdd/Dreamstime.com)

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150 years. The eroded sediments are deposited in places where they are not wanted, such as reservoirs, wildlife habitats, and navigable waterways. China has the highest rate of soil loss of any nation: an annual average loss of about 18 tons per acre (40 metric tons per hectare). Although soil is constantly being renewed, it takes 200 to 1,000 years for 1 inch (2.54 cm) to be created, depending on soil type and climate. Erosion can be prevented by keeping the soil protected from the force of wind and rain. Using mulch (organic material) holds the soil in place while plants grow. Strip cropping alternates a row of a crop plant that leaves the ground exposed with a row of a crop that grows close to the ground and captures blowing soil. Trees planted around a field break the force of the wind, and crops planted in rows perpendicular to wind direction also protect the soil. In the tropics, trees above the fields shelter the crops from the force of falling rain and keep direct sunlight from baking the ground and breaking down organic materials. On hillsides, steep slopes can be terraced and gentler slopes can be contoured to reduce erosion. Erosion in the United States has been reduced since 1985, when Congress created the United States Conservation Reserve Program (CRP). The CRP pays farmers to plant highly erodable cropland with grass or trees instead of food crops. Within a few years, the CRP had removed some 35 million acres (14 million hectares) of cropland, nearly one-tenth of the nation’s total, from production. Better farming practices are also protecting soils in some locations. In arid and semi-arid regions, soils that are highly degraded may become unable to support plants and so undergo desertification. Although desertification is sometimes caused by a decrease in rainfall, human activities are more often to blame. Desertification is most often caused by erosion and salinization. In developing countries, the soil nutrients that were taken up by trees or animals are burned as firewood or as animal dung, which destroys both the nutrients and the chance that the region will recover its fertility.


Soil Degradation (FOF)

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Among the western half of the United States, sub-Saharan Africa, the Middle East, western Asia, parts of Central and South America, and Australia, more than 100,000 square miles (350,000 sq. km) of land are lost to desertification each year. A recent United Nations report warns that one-third of the world’s land surface is at risk for desertification.

Losing Agricultural Land In many locations, the small agricultural communities that grew up to take advantage of fertile river floodplains have grown into modern cities. Prime farmland in these regions is being rapidly lost to development. Land that has been paved over cannot easily be converted back into farmland since the soil loses its structure, and the roots, colonies of bacteria and worms, minerals, and air that were once an important part of it are destroyed. Between 1982 and 1997, in the United States about 39,000 square miles (101,000 sq. km) of farmland, an area equal to Maine and New Hampshire combined, was converted into subdivisions, malls, businesses, roads, parking lots, and other developments. California, which produces half of all of the nation’s fruits, nuts, and vegetables each year, has lost 16% of its richest soils to urbanization. Between 1984 and 1992, California lost 3% of its total cropland, enough land to grow grain to feed 45 million people. More than 50% of the state’s best soils may be lost in the next few decades. At the rate farmland is being developed for other uses in the United States, 110 million acres (445,000 sq. km) will be lost to farming by 2050, equal to the area of Connecticut, Massachusetts, Rhode Island, Vermont, Delaware, Pennsylvania, New York, New Jersey, and Virginia. The United States Census Bureau says that at current rates, 30% of all farmland in the nation will be gone by 2100. Since the nation’s population is also growing, cropland per capita is predicted to decline by twothirds, from 1.4 acres per person in 1997 to 0.46 acre in 2100. In order to maintain the rich and varied diet that Americans are used to, and to export food to feed the growing world population, major advances in biotechnology will need to be made.


The United States is not currently at risk of having people go hungry due to farmland losses, but since arable soils may be lost in other ways (such as erosion), these losses may reduce the ability of future generations to grow enough food. Cropland losses also restrict America’s capacity to supply food to other hungry nations. In developing nations, losses of agricultural productivity may be felt more immediately. Egypt, for example, has all of its arable land on the Nile Delta. The Nile Delta is also where the rapidly growing population must live, since the only alternative is to move into the Sahara Desert. China, with more than one billion mouths to feed, is also urbanizing some of its best farmland. Clearly, there is a lack of large-scale land-use planning in developed and developing regions. Since cities can also be built in regions with poorer-quality soils, such as those that are rocky, sloped, or arid, farmland should be treated as a natural resource that, if wisely used, can be productive far into the future. “Humans tend to congregate where the best resources are. Is it wise to take the best soils and turn them into parking lots?” Marc Imhoff, a biologist at NASA’s Goddard Space Flight Center, said in EOS, the newspaper of the American Geophysical Union, in 2000.

Wrap-up Human activities have destroyed 11% of the world’s farmable land, an area the size of China and India combined, and more than 40% of the rest is now degraded. As a result, every year, the world’s farmers must feed 75 million more people with 27 billion fewer tons of topsoil. Fertilizers cause eutrophication, toxic chemicals contaminate the water, desertification makes lands useless, and on and on. Some people who study these trends suggest that the rise in population and the costs associated with modern farming open up the possibility of Malthusian catastrophes. What will happen when soils can no longer produce as much food, the best lands are covered with houses, or when there are not enough fossil fuels to produce fertilizers and perform farm work?

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12 Food for the Future

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mazing advances in agriculture have allowed the human population to grow astronomically over the past decades. Many people believe that the link between population and agricultural advances will continue until population growth levels off later this century. But the consequences of producing such enormous quantities of food for so many people—in pollution, soil degradation, and natural resources loss—are reducing the abilities of future generations to grow food for themselves. This chapter looks at the long-term problems facing agriculture and discusses the possibility of feeding people by using more environmentally sound practices.

Food Security and inSecurity People suffer from food insecurity when they lack enough food to lead active and healthy lives. People may experience periods of temporary hunger—perhaps seasonally or during a bad crop year— or they may suffer from chronic hunger. Populations that are already 132

Food for the Future

chronically hungry face serious consequences when a catastrophe, such as a drought or a pest infestation, strikes. These populations then fall into the next level of food insecurity, which is called famine. Drought and other naturally occurring events can trigger famine, but the impact of this level of food insecurity is often exacerbated by the political situation. War or corrupt governments, for example, may keep food from being distributed to where it is needed and can cause large numbers of people to starve. About 2 billion people now lack food security at various times. The United Nations Food and Agriculture Organization (FAO) reported in 2003 that 852 million people are chronically hungry. About 60% of all chronically hungry people are found in Asia, and 25% of them live in Africa. But a larger proportion of the African population suffers from hunger: about 33%, compared to 16% of Asians. According to

Famine is prevalent in such developing African nations as Somalia, where this starving child lives. (Andrew Holbrooke/The Image Works)

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the Hunger Project, more than 20,000 people die each day from not having enough food. Food insecurity is caused to varying degrees by poverty, and poverty is caused, to varying degrees, by food insecurity. People who are malnourished are less able to work and take care of their families than people who are healthy. In sub-Saharan Africa, malnutrition costs about $2.3 billion a year in lost productivity, which accounts for more than 1% of the national GDP in the countries of Mozambique, Zambia, and Malawi. Hunger problems can show their effects in a population for years. Malnourished children suffer from stunted growth, cognitive deficits, and a lowered ability to fight off illnesses. In Africa, malnourished children are frequently sick with diarrhea and respiratory ailments and do poorly in school, often falling asleep during class. When these children reach adulthood, they are physically and intellectually stunted, and they are at risk of premature failure of vital organs and higher rates of disease. Malnutrition in one generation then can inhibit the economic growth of a nation for many years. Right now, 33 million children under age 5 are living with malnutrition in sub-Saharan Africa. If a fetus is malnourished during pregnancy, or a child is malnourished during its first few years, that person is more likely to die before reaching adulthood. Malnutrition is a major contributor in the deaths of 5 million African children under the age of 5 each year. Children in sub-Saharan Africa are 22 times as likely to die as children who live in wealthy nations and twice as likely to die as all the children in the rest of the developing world. Some African nations are attempting to combat malnutrition by fortifying flour, cooking oil, and sugar with vitamins. Iodine, which is deficient in the diets of about 2 billion people, is being added to salt in many nations. Ethiopia screens nearly half of all children under 5 for health and nutrition problems, making them eligible for nutrient supplements, de-worming, vaccinations, and fortified food, as needed. But supplying nutrient supplements to all the African children who need it is too large a job, and most children do not receive the help they need.

Food for the Future

Daily per-capita calorie intake by country (FOF)

People have food security if they never go hungry and do not fear losing access to food. The FAO defines food security as “when all people, at all times, have physical and economic access to sufficient, safe and nutritious food to meet their dietary needs and food preferences for an active and healthy life.” Although most people in the United States have more than ample food, some of them still go hungry. According to the U.S. Department of Agriculture’s most recent survey, 12% of the estimated 12.6 million American households lacked food security in 2005. That is, as many as 35 million Americans went hungry at least some of the time during that year. Of those, more than 4 million were chronically hungry. About 3% of American children are malnourished, even though flour and cereal have been fortified with vitamins and

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iron since the 1930s. In Western Europe, the social safety net keeps people from going hungry, but a few nations that were once part of the Soviet Union face significant problems with food insecurity. As bad as food insecurity is today, the situation is better than it was in 1970, when 959 million people were chronically hungry in a world of 3.7 billion people. Many concerned groups, however, call for even greater improvements. For example, the 1996 World Food Sum- mit called for the United Nations to halve the number of chronically undernourished people by 2015, from the 1990 to 1993 baseline number of 823 million. In 2006, a decade after the summit, there were an estimated 854 million chronically hungry people. Although the number represented a slight rise in total numbers, the proportion of hungry people actually dropped a few percentage points because the world’s population grew. The locus of hunger has changed somewhat: Improvements have been made in Asia and the Pacific, Latin America, and the Caribbean, but the situation is worse in South Asia, East Asia, and Africa, where economies are stagnant, population growth is high, HIV is rampant, and standards of living are low.

Increasing Food Production Most experts agree that if we are to feed 8 billion people—many of them demanding a meat-rich diet—by 2030, the world food production will have to increase by at least 40%. In the view of FAO, 80% of this increase will have to come from more-intensive crop production and the remaining 20% from an expansion of arable land, much of which will come from existing forests. Some studies suggest that agricultural advances and expanding farmland will be able to meet rising demands for food. One such model, created in 2002 by the International Food Policy Research Institute, predicted that global cereal production will increase by 56% between 1997 and 2050, and livestock production will increase by 90%, mostly in developing countries. Developing nations will also double their imports of cereal grains by 2025 and triple them by 2050. Income growth and urbanization will increase demand for meats, fruits, and vegetables, all of which demand higher

Food for the Future

agricultural intensity than cereals. At the same time, child malnutrition will decline from 31% to 14% of children by 2050. In sub-Saharan Africa, the number of malnourished people is predicted to increase slightly until 2015 but will decrease slightly by 2050, representing a reduction in the percentage of those who are malnourished. Food production could increase even more with greater investment in production capabilities and education. Doing this would require that more clean water be made available through conservation and better management. By using genetic engineering, scientists could design new crops that are better adapted to the environments in which they are needed. Crops could be engineered to be high yield, disease resistant, cold tolerant, pest tolerant, erosion minimizing, weed sup- pressing, drought tolerant, adapted to adverse soil, nitrogen fixing, and deep rooted. Farmers would need to be educated on how to use more advanced technologies and how to better manage crops for high productivity. Of course, this level of effort would take a great deal of research and the solid support of the local and national citizens who would be the main consumers. Models that incorporate these changes suggest that cereal production could increase by 71% and meat production by 131%. This would halve the number of malnourished children in sub-Saharan Africa between 1997 and 2050 (from 33 million to 16 million) and reduce by more than three-quarters the number of hungry children in South Asia (from 85 million to 19 million). Some advocates support a “doubly green” revolution, in which sound environmental practices are incorporated with Green Revolu- tion philosophies. These people say that being doubly green is the only way to feed the world in the twenty-first century. In the doubly green philosophy, biotechnology, including genetic engineering, is used to design new and better plants and animals, to develop nonpolluting alternatives to synthetic fertilizers, to improve soil quality, and to forge a partnership between researchers and farmers. Other concerned groups and individuals focus on the degradation of the environment that the Green Revolution has brought in the past several decades: the loss of good soil, the loss of arable land, the accumulation of toxic chemicals in the environment, and the enormous

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dependence of agriculture on fossil fuels. In this view, technologically advanced agricultural practices will no longer be able to increase food production at some point. They suggest that the best hope for the future is to use lower-technology solutions.

Sustainable Agriculture Sustainable agriculture is growing in popularity. Sustainable agriculture emphasizes the importance of management over technology. In this philosophy, farms should be profitable enterprises that are part of stable farm communities, while farmers care for the environment through sustainable agricultural practices. Farmers who adhere to these practices farm organically, and the crops and animals they grow are not exposed to synthetic chemicals or pharmaceuticals. These farmers do not utilize GM organisms, artificial fertilizers, pesticides, or other synthetic chemicals. They also avoid the use of nonrenewable resources like fossil fuels for farming or for transporting goods. Sustainable farmers apply the principles of natural ecosystems to agricultural landscapes. They plant a diverse assortment of perennial crops that grow in different seasons. Also called polycultures, these crops avoid the problems caused by monocultures, such as nutrient depletion, soil erosion, and biodiversity loss. Farmers carefully select crops to minimize insect damage by designing a scheme to attract species that will eat the pests. For example, a crop that attracts an insect pest might be planted between a crop that attracts predators that eat those same pests. (By necessity, sustainable farmers must tolerate losing some of their crops to pests.) Only fertilizers from natural sources like manure, rock phosphate, and recycled crop waste are used. Although they may irrigate, growers try not to use more water than is replenished naturally. Animals are raised humanely by not raising them in crowded conditions and by giving them access to the outdoors. Horses and cows perform some of the farm labor while providing manure for crop fertilization. Sustainable farming is best done in communities where farmers can share their machinery, manure, and expertise.

Food for the Future

The products of sustainable farms generally cost more than the products of industrial farms because sustainable farming is more labor intensive and does not trade fossil-fuel energy for food energy. Sustain- able foods are priced to prevent the long-term mining of resources. Food produced by agribusiness is not priced responsibly because many of its costs are not paid by the growers or consumers, but by the people who live nearby whose environment is polluted or whose lifestyles have been compromised. For example, the expense of excess nutrients used on crops is borne by the fishers who can no longer harvest in eutrophic lakes or marine dead zones created by those nutrients. The price of fossil-fuel use is in the costs of air pollution and acid rain, and in the changes brought about by warming temperatures, which will be paid largely by future generations. Currently, it is unclear whether sustainable, organic farming could completely replace conventional farming. In a 22-year study of crop yield, researchers at Cornell University discovered that organically farmed soybeans and corn had the same yield as crops farmed by conventional methods: It took less energy to grow the organic crops and they contained no pesticide residues. A survey of farms in the United States concluded that organic crops yielded between 95% and 100% as much as conventional crops. But a 21-year Swiss study found that the yield for organic crops to be only 80% as high as for conventional crops. On the positive side, much less money was spent on fertilizers and energy. According to Michael Pollan of the University of Califor- nia, Berkeley, who writes on food issues, studies show that small farms produce more food than large farms and polycultures are more productive than monocultures. According to Pollan, the rise of agribusiness as it is today is due more to the desire of large supermarket chains to deal with one food supplier than with several of them. Sustainable farming practices can also be beneficial to subsistence farmers. Pilot projects in Africa were shown to yield improvements in cereal production of 50% to 100%, while simultaneously reducing pollution, protecting or expanding biodiversity, and enhancing habitat quality. The International Institute for Environment and Develop- ment (IIED) suggests that in many countries where it is practiced,

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s ustainable agriculture has dramatically increased crop yields and raised local incomes. To expand sustainable agriculture, governments and nongovernmental organizations would need to work with communities to improve grain strains for the type of rain-fed agriculture that is practiced in these regions. Producing more food requires more water, but often the extra water is only needed to bridge dry spells. Rainwater can be stored in man-made ponds or underground tanks near fields and saved for dry periods. Conservation tillage, which does not use plows, minimizes damage to the soil and enables it to absorb more water and produce more food. A more radical idea, suggested by many people over several decades, was recently presented at the State of the Planet 06 conference by Johan Rockström, executive director of the Stockholm Environ- ment Institute. He proposed reducing or eliminating meat consumption by people in developed nations. In poor nations, grazing animals eat wild grasses that are inedible to people, so raising animals for meat increases the amount of available food. In developed nations, however, the livestock eat crops that are edible. In fact, they must eat about 10 pounds of vegetable matter to produce one pound of meat: This makes meat production a very inefficient use of farmland. In addition, raising livestock, especially in the United States, is extremely energy intensive: Nearly all of the consumed energy comes from fossil fuels. In all, beef cattle from feedlots consume 10 times the number of calories that they provide: Therefore, they are an extremely inefficient food source.

Future Agriculture The Worldwatch Institute believes that land degradation and water shortages will seriously inhibit the ability of people to grow food in the future. While China’s production has been astonishing—the nation feeds 20% of the world’s population with only 7% of the world’s arable land—China is now losing agricultural land to other uses and to land degradation. For these and other reasons, China’s food production has been falling, from 392 million tons in 1998 down to 322 million

Food for the Future

tons in 2005. If there is no turnaround, China will eventually need to import more grain to feed its enormous population. This may have serious repercussions for global agriculture and for the Chinese economy. One very important unknown factor in the future of agriculture is the impact of global warming. Crop yields have increased greatly in the temperate regions in the past few decades, but the effects on productivity of longer growing seasons and increased CO2, which helps plants grow, are difficult to separate from those increases caused by technological changes. In the second half of the twentieth century, the growing season in mid- to higher-latitude locations lengthened by up to two weeks and there was an increase in the number of frost-free nights. Satellite data shows that the lengthened growing season increased productivity of all plants, wild and farmed, in the mid- and high latitudes of the Northern Hemisphere from 1982 to 1991. From 1991 to 2002, however, productivity decreased, possibly due to hotter, drier summers and more widespread droughts. Crop yields appear to have grown in wet regions as rainfall and growing season have increased, but they have shrunk in arid regions, which have become warmer and drier. Insects have spread with rising temperatures, causing additional harm to crops. The loss of crops due to a reduction in rainfall has increased the loss of lands to desertification. Where possible, farmers in arid lands increase irrigation, but where this is not possible, formerly usable land becomes lost. More extreme weather is affecting agriculture, even in the developed nations. In the United Kingdom, drought has caused farmers to increase the percentage of crops they irrigate. The European heat wave of 2003 decreased crop yields by up to 30% in some nations, including Greece, Portugal, Italy, and especially France. Little is known about the effects of climate change on subsistence agriculture. In the Sahel, which borders the Sahara Desert, and where farming is extremely marginal, higher temperatures and lower rainfall have reduced the chance that the strains of plants that are currently being grown will be able to complete their lifecycle and produce food. Some rice-growing regions in Southeast Asia appear to be seeing a slight decrease in productivity.

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Wrap-up Like other major developments in agriculture, the Green Revolution changed the course of human history. The world currently produces more than enough food to feed everyone on the planet, but many people suffer from hunger because the food does not reach them. In the future, though, the costs of the Green Revolution will need to be paid, and it is unclear for how long this agricultural expansion can continue. The adoption of sustainable farming practices would allow food to be produced in perpetuity and should be instituted quickly to stop further losses of agricultural potential.

13 Exploiting Animals for Food

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ore than one-third of the world’s endangered birds and mammals are threatened by overfishing and overhunting, as will be discussed in this chapter. Fisheries are harvested unsustainably, sometimes to the point of collapse, as greater demand brings modern fishing techniques and an increased number of fishing boats. An alternative to wild-caught fish is aquaculture, which is increasing rapidly in importance, but has environmental consequences. In developing nations, hunting continues to threaten many species. Over time, more meat has come from livestock farming, and the practice has become more intensive as human population has skyrocketed.

overFiShing The oceans provide an enormous food resource for the world’s people. Marine fish and shellfish account for a large percentage of the protein that is consumed worldwide and marine animals are the primary 143

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p rotein source for one-sixth of the world’s population. Some of this protein comes from aquaculture, which is the raising and harvesting of seaweed, fish, and shellfish. People eat much of the fish and shellfish harvest, but a growing portion of it is now being made into animal feed, fertilizers, and other products. In the 1950s, 90% of the catch was used as food for people and 10% for farm animals. Now only about three-quarters is for direct human consumption and the rest is for other products. This use of animal protein is only 20% efficient, meaning that a great deal of the energy contained in the fish is lost. Catching fish is now a global business. In 1950, about 20 million tons (18 million metric tons) of fish and shellfish were harvested worldwide. Since then, the world’s population has tripled and seafood production has increased to 130 million tons (118 million metric tons). The incredible increase in the fish harvest was made possible by a tremendous expansion of effort, including a doubling of the number of fishing boats between 1970 and 1990. Fishing methods have also become more sophisticated and more destructive, and fleets now find fish by using sonar scouting vessels (for sound navigation and rang- ing), planes, helicopters, and satellites. Overfishing in both marine and freshwater environments occurs when more fish are taken than are replaced by their young. Overfish- ing is the result of exploding human populations, and the rising expec- tation that seafood should be widely available. In its 2006 biennial report, The State of World Fisheries and Aquaculture (SOFIA), the United Nations Food and Agricultural Organiza- tion (FAO) estimated that most fisheries are fully or over-exploited. Despite international regulations, industrialized fishing has decimated large fish populations so that only 10% of the large fish—tuna, marlin, swordfish, sharks, cod, and halibut—remain when compared to their population in the 1950s. Seven of the top 10 marine fish species are fully or over-exploited. In the United States, the Office of Fisheries Conservation and Management says 41% of species in United States waters are overfished.

Exploiting Animals for Food

The North Atlantic cod fishery on the Georges Bank provides a distressing example of what happens when overfishing causes a fishery to collapse. For more than 400 years, fishers collected cod with hand lines or long lines from small boats. In the late 1950s, however, huge factory trawling ships that scooped enormous numbers of fish from the sea joined the hunt. The fishery peaked in 1968 and, despite increased effort, fish catches dropped in later years. By the time quotas (limits to the amount of fish that can be harvested from a fishery in a season), and then a moratorium, were introduced, the fishery had collapsed. By 2000, the population of mature fish was estimated at 97% below 1990 levels (which were already very low). No one knows if a full moratorium will bring the cod back because the bottom trawlers used by the industrial fishing boats also destroyed the seafloor habitat that the young fish need to survive. When a fishery collapses, fishers are forced to move on in search of new fisheries. For the past few decades, new fisheries have been found in deeper waters or in tropical or polar waters farther away from the nations that practice industrialized fishing. The slow-growing, longlived Chilean sea bass (Dissosticchus eleginoides), originally called the Patagonian toothfish, was one of the species that replaced cod on people’s dinner tables. Now its population is in serious decline, as are the populations of many of these more recently harvested species. To maintain healthy fisheries, fishing must be done sustainably. The first step to protecting a healthy fishery is to understand the life cycles of the fish and their dependence on their environment. Fisher- ies managers must use research to determine how many animals can be taken and at what stage of their life cycles. They then calculate the total allowable catch and ascertain the number of boats that will be permitted to fish and the number of fish that the fishers can take. Quotas are difficult to calculate because there are many unknown factors to consider, and it is often difficult to know if fishers are honestly reporting their catch. If a fishery is determined to be in decline, managers place a temporary moratorium on fishing. Bycatch limits must also be set and adhered to. Bycatch refers to animals that are caught

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or killed in the process of fishing for valuable species and include fish that are too small, that have a low market value, or are species that the fisher is not licensed to catch. Some fisheries now use individual fish quotas (IFQs) to work toward sustainability. With IFQs, the total fishing quota is divided into percentage shares, which are then divided among the fishers using the fishery. Since each shareholder receives a percentage of the total quota, fishers profit by conservation methods that improve the health of the fishery. Receiving an IFQ is considered a privilege and not a right, and fisheries managers can lower the quota if they determine that it was set too high. The weakness in IFQ plans is that fishers may dump lower-value fish so they can fill their quota with higher-value fish. Marine protected areas (MPAs) are ocean areas that are set aside to protect fisheries and safeguard ecosystems and other resources, such as cultural treasures and local economies. MPAs provide a place for marine life to recover from the overfishing and habitat destruction that is occurring outside the protected area. There are more than 4,500 MPAs throughout the world, but they cover far less than 1% of the ocean’s surface. Many of them are small and not well regulated. Fishing is usually allowed in these areas, but there may be restrictions. MPAs are most successful where they protect a specific habitat, such as a coral reef. The number and size of fish of some (but not all) commercial and noncommercial species has increased in some MPAs due to the number of both larger and younger fish that survive to reproduce. Many marine experts favor the expansion of marine reserves, which are set aside as “no take” zones. Marine reserves are natural systems with greater biodiversity than marine protected areas. Marine managers can study marine reserves to more successfully supervise sites outside the reserve. Marine reserves provide an “insurance policy” in which the ecosystem and its species are unharmed. These species serve as a bank for other over-harvested areas. At this time, less than one one-hundredth of 1% (0.01%) of U.S. waters are closed to all fishing. New Zealand and Australia (primarily within the Great


Barrier Reef Marine Park) have national networks of marine reserves. In most nations, at this time, marine reserves are set up only as a last resort when there is a crisis. Many marine scientists support reserves that are set up in conjunction with responsible fisheries management in adjacent lands and waters. Some advocates suggest that at least 20% of the ocean be permanently set aside in reserves. According to the United States National Marine Fisheries Service (NMFS), if people are to continue to get fish from the seas, sustainable fishing will be increasingly important since global seafood demands will more than triple between 2004 and 2025. Consumers can play a role in reducing overfishing by buying fish and seafood wisely. Information on recommended and endangered seafood sources can be found on one of the various lists put out by marine organizations, such as the Monterey Bay Aquarium. Freshwater fisheries are also being overfished, although in the developed nations, intense management is helping some fisheries to recover. Other fisheries, like the lake sturgeon of the Great Lakes, remain critically endangered. In most developing nations, however, little management takes place in their fisheries. Many large freshwater fish in the Mekong River of Southeast Asia, for example, including the world’s largest freshwater fish, the Mekong giant catfish (Pangasianodon gigas), are endangered.

Aquaculture To meet consumer demand, fish and shellfish are increasingly grown by aquaculture, similar to the way people raise meat. In 1970, less than 4% of the total production of fish, crustaceans, and mollusks were from aquaculture, but that number grew to about 30% in 2002, according to statistics from the United Nations. This is a tremendous increase compared with other protein sources: Since 1970, the average annual rise in production by aquaculture has been 8.9%, with only 1.2% for wild fisheries, and 2.8% for land-based farming (of beef, chicken, and other farm animals). More than half of the farmed

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World fish production from capture fisheries and aquaculture from 1976 to 2030. As the contribution from capture fisheries levels off, farmed fish become more important.

species are freshwater fish, and a large proportion of the aquaculture expansion has taken place in China. Currently, about 45% of all fish consumed by people is farmed, and that number is rising. Farmed fish and shellfish must have a safe and healthy environment in which to grow. They can be farmed in earth or concrete ponds, behind barricades, or in cages suspended in water from just offshore to far out in the deeper sea. For a species to be successfully farmed, it must reproduce easily in captivity, be inexpensive to feed, and thrive in the environment in which it is being raised. Because the population density of these farms is high, keeping these animals healthy and their wastes flushed out are high priorities. Currents moving through the cages replace the oxygen and eliminate their waste.


As Dr. Jane Lubchenco of Oregon State University said in World Aquaculture in 2003, “Make no mistake: The Blue Revolution has begun and is needed.” Aquaculture, however, has drawbacks. Facili- ties are difficult to design and operate because storms are common in coastal regions. Costs are often high for land and labor and there are many potential environmental problems. Most farmed fish are genetically altered or hybridized to encourage quick growth. If these individuals escape into the wild, they may out-compete the native fish for food resources and be better able to avoid predators. This causes a decrease in the genetic diversity of the wild population. Enormous numbers of feed fish are needed to supply fish farms. To be useful, these fish must be inexpensive and not eaten by humans. Still, their overuse may reduce the food that is available for other organisms and weaken the marine food web. Just as on factory farms on land, excess food and animal wastes increase nutrients in the water and cause eutrophication. Closely packed animals are prone to disease because parasites, viruses, and bacteria can spread easily among them, making nearby wild populations more vulnerable, as well. To protect their animals from the threat of disease (even if the animals are not diseased), fish farmers release antibiotics into the water. This can affect natural bacterial activity and bring about the evolution of antibiotic-resistant strains of bacteria, possibly affecting wild fish populations and even humans. For aquaculture to be sustainable, it must be done with minimal impact on the environment. Fish that feed lower on the food web, such as filter-feeding shellfish and some other species, consume a smaller amount of energy compared with what they provide. For this reason, they could be farmed more effectively. Native species are a better choice for farming than nonnative species, since they are better adapted to the local environment. Carefully chosen land would also minimize the environmental impact. Shrimp farms, for example, typically replace coastal mangrove forests. Mangroves, however, provide important environmental services, such as serving as a nursery for young aquatic organisms, neutralizing pollutants, trapping sediment, and protecting inland regions from storms. Since about 50% of the

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world’s mangroves have already been destroyed, it is necessary to protect those that remain. Regulating and monitoring nutrients and other pollutants would help avoid contamination. Research is underway into plant-based feeds that meet the nutritional needs of the farmed fish and of the people who consume them, yet have a less-negative impact on the marine environment. Polyculture farming represents a better approach to aquaculture. Practiced in Chinese fish farms for centuries, polycultures, where multiple species of fish are raised, more closely approach the conditions found in a natural ecosystem. Polycultures face fewer threats from disease, and provide an economic safeguard to the farmers if market conditions change to where one species is no longer as economically desirable.

Overhunting People hunt for food, medicines, feathers, furs or skins, ivory, internal organs, and recreation. Early humans used animals for food, warm clothing, and other commodities. As farm food started to contribute a larger portion of people’s diets, and alternative materials replaced products derived from animals for manufacturing goods, hunting became a sport, often reserved for the privileged classes. After many animals were hunted to extinction or near-extinction—buffalo, pas- senger pigeons, and whales among them—hunting in developed nations became highly regulated. In many developing countries, however, hunting is not well regulated. Overhunting is the major problem for one-third of the birds and mammals threatened with extinction. In fact, for 8% of critically endangered mammals, hunting is the major threat. As hunting technology improves, large mammals continue to be targeted, except where they are specially protected. Bushmeat is wild animal meat that is now being seriously over- exploited. For many generations, African forest people hunted wildlife with no impact on populations. Forests were immense and access was extremely limited, so the hunted animals were easily replaced by their


young or migrants into the area. Today, logging roads allow hunters to penetrate much deeper into the forest and to gain access to protected preserves. The hunters are no longer working to feed their families or villages, but often for the money they get from supplying bushmeat to the loggers and workers in other commercial enterprises around the area, which means they kill many more animals. Because many Africans prefer the taste of bushmeat to domesticated meats, bushmeat is available anywhere African immigrants live, including New York, London, Paris, and other large cities. Officials estimate that up to 10 tons (9 metric tons) of African bushmeat arrive in London each day. Recent studies show that between 1 million and 5 million tons (0.9 million and 4.5 million metric tons) of bushmeat are taken annually from the Congo Basin in West Africa, six times the amount that is considered sustainable. Three-quarters, by weight, comes from hoofed animals, such as antelope, but the rest is from predators and other large or scarce animals including 22 species of primates. Of the mammals, 60% of them are harvested unsustainably. Six of the seven species of great apes (the seventh being humans) are taken as bushmeat and are threatened with extinction. The bushmeat trade is controversial. Some people say that the meat is an important source of protein and cash for some of the poorest people in the world and that the trade should be developed to be sustainable. Others say that the meat is supporting people outside the community who have access to other protein sources. In 2002, Dr. Jane Goodall, who has been a world expert on chimpanzees for decades, described to the BBC what happens after the hunters have left a hunting area: “The animals have gone, the forest is silent, and when the logging camps finally move, what is left for the indigenous [native] people? Nothing.” Africa is not the only continent being raided for wild animal meat. As the Chinese economy grows, the demand for exotic foods grows with it. An example of an animal in trouble is the pangolin (Manis sp.), a slow-moving anteater, which is prized for its tasty meat. China’s forests were once full of pangolin, but now they are so rare in China that illegal wildlife traders import them from distant tropical forests in Sumatra

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and elsewhere. Even there, hunters have already killed the larger animals and the size of those being captured now is decreasing. Eventu- ally, those who strive to protect wildlife predict that the shipments to China will dry up, but not before more animals go extinct or become critically endangered. To stop this from happening, animal welfare groups are beginning to appeal to Chinese consumers to stop making the meat of pangolin, and other wild animals, part of their diet. One thing that aids wildlife managers in their efforts to protect wild animals from hunting is the widespread fear of zoonotic diseases. These diseases are spread by pathogens that jump from wildlife to humans. Zoonotic diseases are increasing in type and frequency in human populations because people are increasingly coming into contact with wild animals. The severe acute respiratory syndrome (SARS) virus killed 774 people during the winter of 2002–2003. The virus was transmitted from wild civet cats to humans, probably because they are a popular winter dish in China. HIV is thought to have originated in the central common chimpanzee (Pan troglodytes), and jumped to humans when they hunted or butchered the chimps. A 2005 report of the Wildlife Conservation Society warns that similar outbreaks will become more common as humans come into increasing contact with wild animals.

Livestock Production Most human civilizations changed from relying on wild to domesticated animals for protein many millennia ago. As the human population has grown, so has the number of livestock: The planet is currently home to about 1.5 billion cattle and domestic buffalo, and 1.7 billion sheep and goats. Those numbers do not include pigs, chicken, and turkeys. Live- stock accounts for 40% of the world’s total agricultural GDP. Global production of meat and milk are expected to approximately double between 2000 and 2050. Livestock have an enormous impact on the planet. Grazing and feed production uses 30% of the land surface, while domestic animals contribute 18% of the annual addition of greenhouse gases (in CO2


equivalents) to the atmosphere, more than the amount from transportation. These greenhouse gases include CO2 emissions, mostly due to deforestation, and methane produced by cows during digestion and during the decomposition of manure. To provide enough beef, chicken, and pork to meet the demand, the livestock industry in the United States, and to a lesser extent elsewhere, has created factory farms. Fully 78% of the beef produced in the United States comes from feedlots, where cattle live shoulder to shoulder and are fed corn and wheat, a diet that is not natural to grazers. Chickens are kept in cages allowing about 9 square inches (60 square cm) per bird. These enormous production facilities can house up to hundreds of thousands of pigs, cattle, dairy cows, or chickens. On a typical North Carolina hog farm, between 880 and 1,220 animals live together in a barn with slatted floors for the waste to pass through. 10 million hogs are being grown for slaughter in this state. Animals in such close proximity are susceptible to the rapid spread of disease. Antibiotics are often placed in their feed, even when they are healthy. The excess use of antibiotics is causing bacteria to develop resistance to the drugs, which ultimately makes people and animals more susceptible to bacterial infections. Hormones are used to fatten the cattle: These substances get into the water supply and can cause endocrine disruption in humans. Besides medications, enormous quantities of animal waste pass through a factory farm. Feedlots in the United States produce nearly 300 billion pounds (136 billion kg) of manure daily. Since the feedlots are usually far from farmer’s fields, the manure, which is rich in phosphates and nitrates, is usually not used as fertilizer, but is placed in waste ponds where it releases methane into the environment. Factory farms rely heavily on mechanization, which uses fossil fuels. In a factory poultry farm, machines deliver feed and water and remove wastes automatically. When a chicken reaches the correct weight, it is processed in an assembly line. This efficiency has decreased the price of chicken so that what was once a luxury is now a staple item in many people’s diets. Factory farms use water extremely inefficiently: for example, producing one-half pound (one-quarter kg) of beef requires

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6,600 gallons (25,000 liters) of water. Farm animals also eat a lot of crops, including 95% of the world’s soybeans. Because the cost of starting a mechanized farm is high, factory farms are owned by corporations, which can afford it. Farmers are contracted to grow the animals for these corporations, which take the product but leave behind the pollutants. These feeding operations work under laws that were designed to protect small farms that did not house enough animals to cause major environmental damage. Whereas the World Bank once supported factory farming in developing nations, it changed this policy because of the deterioration of social structure and the environment that large-scale farming brings. To be socially and environmentally sound, growing food animals would follow a sustainable agriculture model in which consumers pay farmers a fair price to raise meat that does not harm the long-term productivity of the land or the health of the environment.

Wrap-up Fish are the only wild animals that are now routinely caught for food in the developed nations. But increased demand, coupled with advanced technologies and a greater number of fishing vessels, has resulted in the reduction, or even the collapse, of many fisheries. Typically, when a fishery is no longer commercially viable, the fishers move on in search of new fishing areas, but there are now fewer fisheries to move on to. Wild animal hunting no longer provides much food in many parts of the world, but where it does, the game animals may be threatened with extinction. To supply meat for the people in some developed nations, domesticated animals are being produced cheaply in factory farms. These feeding operations are extremely damaging to the environment and often to the nation’s social structure. As with crops, the long-term effects of producing food will need to be considered so that meat and fish can be supplied to people in a sustainable manner. While this may cost consumers more, it will assure that fish and meat will be available to future generations.

14 Forests and Deforestation

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cosystems are disappearing as people convert the land to other uses or use up the resources that are found within it. As will be discussed in this chapter, ecosystems that have already been lost, or are now being lost, include all types of forests. Forests and the products harvested from them are extremely important to people and to the planet. Forests around the world are being rapidly logged for resources or converted to farm or ranch land. With their own forests seriously depleted, people in the developed nations are looking to tropical forests to meet their needs for wood. Sustainable forestry, in which managed forests are treated like natural forest ecosystems, are becoming more common, and it is now possible to buy wood products from forests that are farmed sustainably.

ForeSt tyPeS Forests are common worldwide where temperatures are not too extreme and there is enough water. The type of forest found in a region depends on its climate. Forest biodiversity varies with the type of forest: 155

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High-latitude forests have a much smaller number of plant and animals species than the tropical forests that are located in lower latitudes nearer the equator. Boreal forests stretch across enormous areas of Canada and northern Eurasia, where growing seasons are short and most precipitation falls as snow. Firs are the dominant trees here: They can survive frosts and have tough, needle-shaped leaves that shed in the winter. Although boreal forests have low species diversity, they are still home to many types of animals and are an important summering stop for migratory songbirds. Temperate forests extend across the temperate regions of North America and Eurasia, where the climate is cool and annual rainfall is high. Deciduous forests are found where summers are hot and winters are cold. To avoid freezing, deciduous trees lose their leaves in the winter. Evergreen forests are found where summers and winters are mild. Evergreen trees do not lose their leaves seasonally. Spectacular forests of coastal redwoods (Sequoia sempevirens) and Douglas fir (Pseudotsuga menziesii), both of which can grow to more than 300 feet (92 m) tall, are found in western Canada and the United States. Tropical rain forests are more hospitable to life than other forest types because temperatures are fairly constant year round, and rainfall is abundant. Tropical rain forests support the greatest biodiversity of any ecosystem on Earth: an estimated 50% to 80% of all species. Plants are at the heart of rain-forest biodiversity. Each hectare (2.47 acres, 10,000 sq. m) of tropical rain forest contains 350 to 450 tree species with only one or two representatives of each species. By contrast, temperate rain forests have anywhere from 6 to 30 species per hectare, and three or four species account for almost all trees. The diversity of plants in the rain forest creates an enormous number of living places for animals, so a tremendous variety of birds, mammals, and reptiles are able to live throughout the forest. The world’s largest rain forest, the Amazon, has the most biodiversity of any ecosystem in the world, with up to 30% of the world’s total plant and animal species. Much of the Amazon is remote, so many of these plants and animals remain unknown to science.

Forests and Deforestation

Forest Uses In the developing world, people use forest products for constructing shelter and making rope. They also harvest fruits, nuts, and other foods. The forests support the birds and mammals that humans hunt, provide the medicines they use to treat illness, and supply the firewood they use to cook their food. People in the developed nations have replaced wood with manufactured materials, like plastic and fiberglass, for many uses, but forest products are still important for construction, furniture, paper products, and firewood. Because forests contain such an enormous number of plants, they provide very important ecosystem services to the planet, as follows: 

Forests are major contributors to evapotranspiration. About 75% of the precipitation that falls on a healthy forest is evaporated back into the atmosphere. Forest plants absorb water and contribute to the health of the soils, which also absorb water.  Forests cleanse the atmosphere by filtering some air pollutants, like carbon monoxide. Plants and their soils absorb CO2 and forests act as enormous carbon sinks, which assists with keeping down the levels of greenhouse gases in the atmosphere.  Forests retain water. Their soils trap the water, which then filters down to recharge groundwater aquifers. Forests are cut for their timber and wood products, but many of them are cleared for agriculture, grazing, and urbanization. The uses of forest materials or the land that they are cleared from are 

Fuel: Half of all downed trees are used for fuel. In developing nations, firewood is often the most economical and easily accessible energy source.  Wood and paper products: At least half of the world’s timber and nearly three-quarters of its paper are consumed by 22% of the world’s population, mostly by those consumers

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living in the United States, Europe, and Japan. Global paper use has increased six-fold since 1961. Cattle ranching: Ranchers clear tropical rain forests to create cattle pastures. Some of this beef is exported to developed countries and made into fast-food hamburgers and frozen meat products. For every ¼ lb. (113g) hamburger made from cattle grazed in cleared rain forest, about 55 square feet (5.1 sq. m) of rain forest (the size of a small kitchen) is destroyed. Agriculture: Forests worldwide are cleared for farmland. These farms are economically important to families living on subsistence agriculture and to corporations for larger farms. The farms are also important to the region, where they supply food and contribute to the local economy. Resource extraction: Mining for minerals and drilling for oil destroys forests. Roads built for access to these resources open up once-pristine areas for logging, hunting, and other destructive activities. Industrial development: Pipelines, power lines, roads, dams, and other infrastructure are built to open forests for largescale industrial development.

Deforestation Deforestation is the loss of forest due to human activities. Deforestation occurs for the reasons cited above, but also happens unintentionally— by wildfires, for example. Uncontrolled grazing can keep young trees from growing to maturity and can contribute to forest degradation. The underlying causes of deforestation are economic need and population growth. Nations with higher standards of living consume more timber and wood products, and developing nations depend on the income that timber sales generate. Growing numbers of poor people depend on cleared land for subsistence agriculture. Humans have damaged or destroyed about half of the world’s original forests. More than half of these losses have occurred in the


Deforestation associated with the Tierras Bajas project in eastern Bolivia as seen from the international space station on April 16, 2001. People are being resettled in the Amazon to cultivate soybeans. Each “pin wheel” pattern is centered on a small community; the communities are spread across the landscape at 5-km intervals. (NASA/Earth Sciences and Image Analysis Laboratory/Johnson Space Center)

past 50 years. The temperate forests have been the hardest hit, since Europe and the United States have been logging for centuries. The United States, once a vast frontier of seemingly limitless trees, now has less than 4% of its original virgin forest. Canada still has enormous tracts of boreal forest, and the nation has committed to preserving sizable areas. With the temperate forests largely logged out, developed nations have increasingly turned to tropical and subtropical forests for wood products. Tropical rain forest once covered as much as 12% of the planet’s land surface (6 million square miles [15.5 million sq. km]), but that percentage has now fallen to only 5.3% (1 million square miles [2.6 million sq. km]). About 120,000 square miles (310,000 sq. km),

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an area nearly as large New Mexico, the fifth-largest state, is lost each year, and the rate of destruction is increasing. Current projections show that tropical rain forests may be gone in as little as 40 years. Deforestation has many adverse effects that reduce or eliminate the forest’s ecosystem services. The most obvious effect of deforestation is the loss of diversity in organisms or genes. Species may vanish locally or may become extinct. When a species becomes extinct, its potential uses are lost. This is a problem because organisms are an extremely important source for prescription drugs. The Pacific yew tree (Taxus brevifolia), for example, is the source of the important anti-cancer drug Taxol. More than 75% of the top 150 prescription drugs are derived from, or are synthesized to mimic, chemicals found in plants, fungi, bacteria, and vertebrates (those animals with backbones). Wild organisms are also a source of desirable genes. Eradicating a forest changes the way water moves through a region. Reducing evapotranspiration can alter the amount of precipitation that falls in the deforested region and nearby areas. Deforestation increases erosion to between 500 and 10,000 times an area’s normal rate. The loss of topsoil means that nutrients are lost at six to eight times the rate of a forested valley. Because tree roots hold soil in place, when slopes become stripped of trees, they are much more prone to landslides. Nutrient loss and erosion cause long-term deterioration of the soil, which brings on desertification in arid and some semi-arid climates. Furthermore, eroded sediments are carried by rainwater into waterways, where they silt up lakes, ponds, man-made reservoirs, and even seas and oceans. Sediment clouds the water and hinders photosynthesis in aquatic plants. Entire ecosystems, such as coral reefs, may be buried by sediments. Estimates are that excess sediments due to deforestation have killed 75% of the coral reefs found in the Philip- pines and in the Caribbean Sea off of Costa Rica. Plants contain most of the nutrients in a tropical rain forest ecosystem. Plants absorb nutrients. When the plant dies and decays, the nutrients enter the soil briefly, but then are quickly taken up by another plant. When the plants are removed, whether for harvesting


or by slash-and-burn agriculture, the nutrients are taken with them. Tropical rain forest soils, therefore, make for very poor farming. Deforestation contributes to global warming by releasing the carbon stored in plants back into the atmosphere. When loggers burn the debris, the plant matter releases its absorbed CO2. Of course, deforested areas are no longer able to absorb CO2. Deforestation, mostly for agriculture, destroys 50,000 square miles (13 million hectares) of forests worldwide a year. Reforestation, which can either occur naturally or be done by people, makes up for some of the loss: Between 2000 and 2005, the average amount of forest lost per year was 28,000 square miles (7.3 million hectares). This represents a decrease in the rate of forest loss from 34,000 square miles (8.9 million hectares) per year during the period from 1990 to 2000.

Forest Management Forests still exist as wild lands because either people have not yet moved into them or they have been set aside for preservation. Many forests are managed for their resources. The most extreme type of managed forest is a tree farm, also called a plantation. Tree farms are monocultures, where only one species of tree is grown. Little attempt is made to grow native trees, and the species chosen is usually resilient and fast growing. Pine (Pinus sp.), spruce (Picea sp.), and eucalyptus (Eucalyptus sp.) are common species, as are hybrids between two species or genetically modified species. Since the trees are often not native to the area, and since they are all the same size, they do not make good habitat for native animals. Plantation trees are grown with the same techniques used for any other crop. For example, these trees are planted all at the same time and in rows, and they are harvested over a period of just a few months. A tree farm bears little resemblance to a natural forest ecosystem. At this time, forest plantations make up less than 5% of the total forested area worldwide, but they account for 20% of current wood production. After logging, some forests may be allowed to grow back naturally. In some cases, however, when the conditions are not favorable, trees

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do not recolonize the area, which becomes grassland or some other type of landscape. Foresters may sometimes attempt to reestablish a forest after it has been logged by rejuvenating the soil and planting seedlings. Companies in countries like Costa Rica and Panama are reforesting old cattle pastures for future timber harvests. These forests are typically polycultures, so they more nearly resemble a natural forest than most tree plantations. Much of the logging done today takes place in the tropical forests of the developing nations. Oftentimes, the local people take from the forest ecosystem the same things they always have: nuts and fruit, fish, game, and other necessities. When international timber companies want to log the forest, however, the national government leases the land, often with little benefit to the local people. The timber company takes all the trees and usually fails to replant them. The nation makes some money from the raw lumber, but the high-value items, like furniture and paper, for example, are manufactured in more developed nations. The local people see little of the economic value of their forest resource and their ability to live off of it is lost. When a logging company has a long-term lease, or they own the land outright, they are more likely to practice sustainable forestry.

Sustainable Forestry The goal of many foresters, particularly in Europe and North America, is to manage forests sustainably. Sustainable forestry practices are meant to mimic natural processes as much as possible. Forests that contain all stages of tree growth and the right amount of woody underbrush more closely resemble natural ecosystems and make better homes for forest animals. Healthier forests contain healthier trees. In such a situation, those that are logged yield more wood of a higher quality. In sustainable forestry, trees are logged individually and are carefully chosen with regard to the space between them and the amount of underbrush that is growing beneath them. Only as much timber is removed as the for-


est can grow back without damage to the soils, the watershed, or the seed source. In many forests, that means no more than 25% to 35% of the trees can be harvested, although this number varies depending on the forest type. Some old trees are kept standing to serve as a seed source since their age means they are well adapted to their environment, unlike young trees that may be more in danger of being killed off by disease or fire. In sustainable boreal and temperate forests, fires are allowed to burn because they are part of the natural ecosystem, although these burns are controlled. Consumers can now choose wood products that have been created from sustainably managed forests. Certification programs establish criteria and forests are evaluated by independent auditors for how they match those criteria. There are several certification systems, and each one has its own criteria. The Canadian Standards Association, the Forestry Stewardship Council, and the Sustainable Forestry Initia- tive are three main programs. These programs have certified forests of roughly 1,000,000 square miles (2,600,000 sq. km), of which nearly half are located in Canada. (Becoming certified is difficult for developing nations.) Consumers can further reduce wood consumption by recycling paper. Americans recycle about 50% of their paper, but Germans are a model for the world with a recycling rate of 75%. A forest may also be managed for reasons other than timber and wood products. The Area de Conservación Guanacaste (ACG) in northwestern Costa Rica is a sustainable forest that is being managed for its socially useful “crops.” Besides the forest’s aesthetic and intel- lectual beauty, these crops contribute to ecotourism (tourism that is environmentally and culturally sensitive); biological education, for local children and Costa Rican and international researchers; biodiversity services, for pharmaceuticals and other products; and ecosystem services, such as sequestering CO2. The use of all of these crops is sustainable as long as it is organized, controlled, structured, and done with full understanding of the organisms and ecosystems. ACG scientists are expanding this forest ecosystem by buying and converting adjacent ranchland. It is believed that if the ACG provides useful

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services and jobs, the local people will want to keep it as forest instead of converting it to other uses.

Wrap-up Even as virgin forests dwindle, trees will still need to be grown to meet society’s needs. Forests can be managed as tree farms, but these provide little biological diversity and few ecosystem services. Forests can also be managed sustainably so that they can produce timber but still be viable ecosystems for the indefinite future. If future generations are to have access to forests and the services they provide, more forests will have to be managed sustainably, and a good number of them will need to be preserved in their natural state.

PART FIVE

OVERPOPULATION REVISITED

15 Are There Too Many People?

E

cosystems are disappearing due to the creation of farmland and the building of cities. Pollutants are contaminating the air, water, and land and are causing global temperatures to rise. Species are going extinct at a high rate, mostly due to habitat loss, but increasingly due to other environmental changes, like global warming. All of these changes are the result of human activities. It remains to be seen whether the planet’s carrying capacity for humans has been exceeded, or whether people can learn to live sustainably.

tHE CurrEnt EXtInCtIon CrIsIs Biologists agree that the greatest threat to life on Earth is the degradation and destruction of ecosystems. The land from nearly half of the planet’s ice-free areas has been transformed for human uses: By 2032, more than 70% of the Earth’s surface will likely to have been altered. Incred- ible losses have already occurred in the ecosystems of the developed nations, such as in the temperate forests of North America and Europe. Destruction is currently accelerating in developing nations, particularly 167

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in wetlands and tropical rain forests. Each transformed ecosystem is no longer the perfect habitat for its native species, and many of those species are likely to experience population reductions, or even extinction. Habitat loss is the primary threat to 85% of endangered and threatened species in the United States, and possibly even more globally. The rate at which species are going extinct worldwide is increasing. The millennium ecosystem assessment by the United Nations Environ- ment Programme (UNEP) found that the current global extinction rate is between 100 and 1,000 times higher than the average over geologic time. The extinction rate in 50 years is forecast to be more than 10 times the current rate. Biologists call species loss of this magnitude a mass extinction. Although mass extinctions have occurred in the planet’s history—caused by asteroid impacts, climate change, or unfathomably large volcanic eruptions—none of these events has been caused by the actions of a single species. Worldwide, an estimated 30,000 species are lost per year, or an average of about three per hour. At this time, most of these losses are taking place in the biologically rich tropical regions. The World Conservation Union, or the International Union for the Conservation of Nature and Natural Resources (IUCN), projected in 2004 that about 1 million land organisms will disappear in the next half-century. In all, some 12% of birds, 20% of reptiles, at least 32% of amphibians, as many as half of the plant species, and 25% of mammals (including lions, rhinos, tigers, and most primates) could be extinct by the end of this century. Harvard University biologist E.O. Wilson has an even more dire prediction: He estimates that one-half of all species on Earth will be extinct by 2100. As Jeffery Sachs stated at the State of the Planet 06 conference, “Every single major ecosystem on the planet is under profound stress. It should be the number-one talked-about issue, because it is right at the core of our needs, our survival, and our future prospects.”

Easter Island: A Cautionary Tale In the middle of the Pacific Ocean, 2,300 miles (3,700 km) west of Chile, lies tiny Easter Island, only 66 square miles (171 sq. km) in area. Known as Rapa Nui to its inhabitants, the volcanic island is

Are There Too Many People?

unique because of its moai, the beautiful and eerie stone statues built by the island’s inhabitants. In addition to these wonders, Rapa Nui is becoming known for a different reason: “Scientists recognize Easter Island as the best example of an environmental catastrophe caused by humans,” said Jared Diamond in his 2004 book Collapse: How Societies Choose to Fail or Succeed. In this catastrophe, overpopulation and overuse of resources played critical roles. Rapa Nui was colonized by Polynesians in about a.d. 900. The Poly- nesians were clearly looking for a new home since they arrived in their boats with bananas, taro, sweet potatoes, sugarcane, paper mulberry, and chickens. Inadvertently, they also brought rats. The island they found was a rich and diverse subtropical forest of tall trees and woody brush. The Easter palm grew more than 65 feet (25 m) tall and 3 feet (1 m) in diameter. The tallest trees were the Toi (Alphitonia zizyphoides) and Elaeocarpus rarotongenesis, which grew up to 100 feet (30 m) and 50 feet (15 m), respectively. Native species of land birds, lizards, and turtles wandered the land and seabirds nested on its shores. The island presented a few difficulties to the colonizers. It is cooler, windier, and drier than most of the other Polynesian islands, and only one freshwater stream runs across it, although water collects in pools in other locations. Offshore, the island drops steeply off into the deep sea, and the relatively cool water does not allow coral reefs to grow. When the settlers arrived, common dolphins (Delphinus delphis) swam in the cool waters nearby, as did seals, and large fish like tuna. Once the Polynesians arrived on Rapa Nui, they did not receive any outside influence or help. Initially, the island was a paradise. The people consumed nuts and took sap from the Easter palm to make into syrup or wine; they also made its fronds into baskets, mats, and boat sails, and used its trunks to construct rafts. They carved the tall trees into canoes, which gave them access to the fish and dolphins offshore. They also used various trees and shrubs for construction, carving, rope, tapa cloth (for clothing), harpoons, outriggers, fruits, nuts, and firewood. The dead were cremated in enormous firewood funeral pyres. Archeologists have excavated garbage dumps (more appealingly called middens) to understand the evolution of cultures. (Middens

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hold the remains of what people ate, wore, and used: The bottom layers represent the earlier years, and the top layers the later years.) On Rapa Nui, the lower levels of middens contain many bones from common dolphins, land and sea birds, seals, and large fish. The presence of charcoal indicates that this wide assortment of meat was cooked before being eaten. The Polynesians also farmed and raised chickens in stone coops. The island was inhabited by 11 or 12 clans, each with its own territory that covered coastline, flatlands, and uplands. These clans also shared the island’s resources. The statues they left behind look eerily alike: a large head set on a legless body wearing a loincloth. Some have eyes constructed of a white coral iris and a pupil of a red volcanic rock. Some have pukaos, red stone cylinders that weigh up to 12 tons (11 metric tons), placed on top of their heads. Some of the 300 platforms on which the moai rest are constructed of large stone slabs up to 13 feet (4 m) high and weighing up to 10 tons (9 metric tons) placed in a rectangle. The slabs serve as retaining walls for the hundreds of tons of rock rubble placed inside. The moai were erected near the coast with the statues facing inland in the direction of the clan that erected them. The cost of creating and mounting the moai was tremendous. Spe- cial craftsmen carved the statues in the quarry. When carving was complete, the statues were placed in wooden sleds that were moved across the land on heavy logs spaced along the ground and connected as a sort of ladder. Workers gathered to pull simultaneously on thick ropes that were attached to the sled. Experiments with modern Easter Islanders have shown that 50 to 70 people working five hours a day could transport a 12-ton (11 metric ton) statue nine miles (14 km) in one week. The largest statues might have required the work of 500 adults, which would have been possible only when the island population was at its highest. Once a statue reached the platform, it was levered up using stones and logs until it stood vertically. Diamond estimates that the clan probably needed about 20% more food than usual to support the building and transport of the moai. The bulk of this activity began in about 1300 and took place over the 300 years


Moai on Easter Island. (Akivi33/Dreamstime.com)

that coincided with the years of greatest productivity for the upland plantations. Although farming the upland areas was more difficult than farming the lowlands, farms moved uphill because there was more rain. During the best years from 1400 to 1600, the population may have risen as high as 30,000. The Rapa Nuians harvested tremendous amounts of wood from the island’s forests to transport the moai and for other uses. The people also cleared trees to grow food. While human activities took a toll on the forest, so did the rat population: Every nut from an Eas- ter palm that has now been found was previously chewed by a rat. Since damaged nuts could not germinate, mature trees could not be replaced. As a result, the island’s trees began to disappear in the

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sixteenth century. Easter palms and other Rapa Nui island trees are now extinct. Without trees, there was no material left to make boats, cloth, rope, and tools, or for warmth and cooking food. With the ecosystem so altered, native birds and mammals died out or were hunted to extinction. Eggs and young animals were probably eaten by rats. The higher layers of the middens have few or no bones of fish, dolphins, and seabirds since the Rapa Nuians did not have logs for making boats to go fishing. Wild fruits and nuts were no longer available. As people became hungrier, they decimated the larger shellfish and began to eat smaller species. As the lands were deforested, topsoil eroded away, and nutrients became scarce. The upland plantations ceased to be productive, and between 1600 and 1680 they were abandoned. “The overall picture for Easter is the most extreme example of forest destruction in the Pacific, and among the most extreme in the world: the whole forest gone, and all of its tree species extinct. Immediate consequences for the islanders were losses of raw materials, losses of wildcaught foods, and decreased crop yields,” writes Diamond in Collapse. With so many food resources gone, the seventeenth and eighteenth centuries were a time of starvation for the islanders. The number of home sites on the island decreased by about 70%. To memorialize this time, the island has many small carved statues of starving people “with hollow checks and protruding ribs,” says Diamond. The upper layers of the middens show that the Rapa Nui in the later years ate chicken, rats, and high-carbohydrate crops. Deforesta- tion caused rainwater to run off the land quickly and water for drinking and domestic uses became scarce. Although there is some doubt about this, many anthropologists believe that the Easter Islanders then resorted to cannibalism, a hypothesis that is supported by oral tradi- tion. Certainly, evidence of human bones that were cracked to extract the marrow has been found on the island. When food was abundant, the building of the moai appears to have been peaceful. Over time, the statues increased in size, a sign that there was competition between chiefs and possibly an attempt to appease the gods to provide more food. As deforestation progressed,


the islanders were unable to make lumber or ropes for transporting the statues. The last moai were erected around 1620, and many were abandoned in the quarry and along transport roads. As they failed to deliver food and water year after year, the authority of clan chiefs and religious leaders grew precarious, and their relationships with the gods were questioned. The leaders were overthrown in a military coup in 1680. Civil war erupted. Angry residents toppled the moai so that they would break when they hit the ground. Some of the moai have been reconstructed for the benefit of the tourists who visit the island. The first record of contact between Rapa Nuians and Europeans took place on Easter Sunday (hence the name Easter Island) in 1722. The captain described 2,000 to 3,000 islanders who possessed only small, leaky canoes for transport. His log does not mention the presence of trees over 10 feet (3 m). In 1774, Captain Cook stayed at the island for four days. At that time, some of the moai were still standing. He described the residents as “small, lean, timid, and miserable.” In the following centuries, many Rapa Nuians were killed by European diseases or were removed from the island to become slaves. By 1877, the island’s population had fallen to only 110. Diamond uses what happened on Easter Island as an allegory, “a worst-case scenario, for what may lie ahead of us in our own future.” The nations of the world are now as integrated in their sharing of resources as were the clans on Easter Island. Rapa Nuians could not rely on help from outside, nor can humankind today. As then, there is nowhere for excess population to go. Diamond recognizes that this is an imperfect metaphor: Easter Islander population numbers were much lower and their tools were relatively primitive, compared to people in the world today—but how much does having more people in a larger world with more sophisticated tools really help?

Results of Overpopulation and Over-consumption The carrying capacity of a species in a location is exceeded if resources are being depleted faster than they are being replenished.

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Since 60% of resources are now being used at a faster rate than they are being replaced in nature, the carrying capacity of the planet is being exceeded by the current human population. This means that for the current level of consumption, the planet is overpopulated. Some of the effects of overpopulation and over-consumption that are currently being seen are      

difficulty providing clean water and sewage treatment for large numbers of people. overuse of natural resources including forests, fossil fuels, and minerals. loss of arable land due to urbanization and soil degradation. loss of ecosystems and consequent species extinctions due to land-use changes. increased pollution of the air, water, and land. atmospheric changes leading to climate change.

Many people are also suffering in regions that are overpopulated. They are experiencing         

starvation and malnutrition. high incidence of poverty. high infant and child mortality. low life expectancy. increased infectious diseases due to overcrowding, ecosystem disturbance, and overburdened health care systems. high unemployment and resultant social problems. high crime. fighting and war due to competition for resources. overused human infrastructure: roadways, health care systems, etc.

Asked the approximate value of Earth’s carrying capacity for people, Paul Ehrlich, in an interview with the online magazine Grist in August, 2004, stated, “Carrying capacity depends on the behavior of


the organisms (people, in our case) involved—the carrying capacity of Earth for vegetarian saints is much higher than for the present mix of people. For that present mix it is easy to show we’re in overshoot— way above the carrying capacity.”

How Population Will Grow Nearly all of the growth in population is in developing and poor nations, and much of that is in the slums that sprawl around major cities. Slums grow because farmers lose their ability to produce enough food to feed their families—due to changes in agricultural practices, land degradation, adverse weather, and increased family size. They then move into cities to look for work, which often is not available. Even in rapidly developing nations, these poor people are excluded from rising standards of living. Today, 600 million slum-dwellers do not have adequate shelter and 400 million do not have latrines. Slums may be located next to major roads, factories, or dumpsites so that the inhabitants are exposed to high levels of air and water pollution. Most of these people lack garbage collection and proper sanitation. Poor drainage allows wastewater to collect, creating an ideal environment for diseasecarrying insects to breed. Crowded conditions also allow diseases to spread more rapidly. By 2030, nearly 5 billion people, 60% of the world’s population, will live in cities and towns, mostly in slums. As the environment deteriorates, many places will become unliv- able. If ecosystems collapse, economies may collapse with them, leaving people without life’s basic necessities. If global warming causes high temperatures to melt ice sheets, then sea levels will rise and inundate billions of people’s homes with water when storms strike. Situations like these will create what are called environmental refugees, people who are displaced from their homes by environmental deterioration. The group includes climate refugees, those who are displaced by increases in extreme weather events, sea-level rise, or any other effect of climate change. There may already be millions of environmental refugees. Immigrants to the United States and Europe are sometimes driven by deteriorating soil and water conditions in their

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Slums in Hong Kong resulting from urban decay. (sumnersgraphicsinc/iStockphoto)


native lands. The United States may already have its own environmental refugees—those Americans who were driven from New Orleans and other Gulf Coast locations by the 2005 hurricanes Katrina and Rita. The Red Cross says that the number of people in the southwestern Pacific who have been affected by weather-related disasters has increased 65 times in the past 30 years. Many of these people have already become, or will soon become, climate refugees. According to a 2005 United Nations report, by 2010 there may be as many as 50 million environmental refugees worldwide, driven from their homes by rising sea level, desertification, and catastrophic weather events. The U.N. is urging the international community to recognize “environmental refugees” as a refugee category, which will make them eligible for the same assistance given to traditional categories of refugees.

This camp in Pakistan, November, 2005, served as shelter for children and their families displaced by an earthquake. (Zoriah/The Image Works)

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People in the developed nations may think that the problems caused by climate change will largely leave them untouched. But, like New Orleans, low-lying coastal cities will need to be protected from rising seas or they will be lost. Warmer temperatures will cause extreme weather events to increase in frequency. The combination of higher seas and more-extreme weather has the potential to create enormous numbers of environmental refugees within the developed nations. There is also the risk that, if people in the developed nations are seen as being better off than people elsewhere, increasing numbers of immigrants, legal or illegal, will be clamoring to move in.

Can Sustainable Development Be Realized? One very important step toward achieving sustainable development is to continue to reduce population growth rates. World fertility rates have decreased from six children in 1960 to three today due to economic development and access to family planning. When women are educated and allowed to make reproductive choices, their productivity, economic situation, environmental management, and reproductive health improves: Child and maternal mortality decreases and the daughters they do have are more likely to be educated; demand for family planning increases and birthrates go down, as do abortion rates, including those for unsafe abortions; the spread of sexually transmitted diseases slows down, along with the spread of HIV/AIDS. If sustainable development is to be achieved, science will play an important role. Scientists need to better understand how the world’s ecosystems and climate work so that they can recognize how human activities are changing them. Scientists will also help to develop technologies that can be used wisely to solve problems. Used correctly, genomics can lead to better health management, improved aquaculture for supplying fish and seafood, and better agronomy to increase the types of environments in which food can be grown. Steps can be taken that lead to better water management practices. Engineering advances can introduce better ways to use resources, such as the development of cleanly burning fossil fuels and methods to capture and sequester


carbon. Alternative energy sources, such as solar power, can also be developed. Scientists will need to help politicians and citizens understand the problems and get onboard with the solutions. Citizens will need to change their behavior to reduce the impact everyone has on the planet, and politicians will need to lead the way, by both understanding the problems and convincing citizens that the changes they advocate are the right ones. As Jeffrey Sachs said at the State of the Planet 06 conference, “The fact of the matter is we need science and engineering, which is the translation of science into practical objectives. We need science and engineering right in the forefront if we are going to achieve sustainable development on the planet. If we don’t achieve sustainable development on the planet, what that portends for us is a world of much greater risk and upheaval than we have right now.”

Wrap-up The Rapa Nuians made many mistakes, primarily by not recogniz- ing that their resources were limited. They also did not understand the effect their actions would have on the rest of their island: That if a slope was deforested, for example, it would no longer be useful for farming. This same story plays out in many ways in the modern world. The question is whether people can change course now and stop this sort of destruction from happening on a planet-wide scale. As Jeffery Sachs said at State of the Planet 06 conference, “I’m not making a forecast but I am making a warning. If we don’t change our trajectory and if we don’t harness science and technology to do it in a wise way we’re going to be building up a lot of pressure on each other and on our planet in ways that will be very dangerous in the years to come.”

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he Reverend Thomas Malthus predicted in 1798 that, if left uncontrolled, human population would grow to exceed the amount of Earth’s resources that could support it. The result would be pestilence, famine, or war. Over time, all of these Malthusian catastrophes have occurred in local or regional groups. Disease has wiped out countless people living in high-density populations. The bubonic plague exterminated an estimated 75 million people in the squalid conditions that existed during the fourteenth century. Today, the AIDS pandemic is killing people around the world, but particularly in densely populated sub-Saharan Africa, where there are few resources available to stop it. Thousands of years ago, the people of Easter Island thrived materially and culturally until their population exploded. As a result, they overused their resources, to the point where they cut down all their forests: The end result was starvation and civil war, which greatly reduced the population. Famines occur in modern times. One can happen when people who are already living on the edge are forced to undergo even a minor

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alteration in normal conditions: for example, when there is a drought, or when the human population grows too high to be supported by the available resources. Sometimes, this famine leads to war. Although the genocide in Rwanda in 1994 has been blamed on ethnic hatred, in his book Collapse: How Societies Choose to Fail or Succeed Jared Diamond links that event to overpopulation. Rwanda is one of the most densely populated countries in the world, and by the late 1980s, all forests outside the country’s national parks had been cleared, all arable lands were being farmed, and the rate of soil erosion was heavy. Famine spread as a drought ensued, possibly due to precipitation changes caused by deforestation. Even when there was enough rain, many people experienced chronic hunger because there was not enough arable farmland available per person. In this desperate situation, Rwandan politicians sought to maintain their hold on power by fanning the flames of ethnic hatred. The ensuing Rwandan genocide claimed up to one million lives, about 10% of all Rwandans. Many of these people were murdered, but some died of starvation that was exacerbated by the war. According to Diamond, the Rwandans themselves state in interviews that there were too many people for too little land, and that war is sometimes necessary so that the survivors can better support themselves. Despite these catastrophes, Malthus’ predictions have not come true on a global scale so far. Although the population has increased nearly seven times since Malthus made his predictions, and many people suffer without enough to eat or drink, on the whole, resource availability has kept up with demand. More food has been provided by ever-advancing agricultural methods. This approach to agriculture, however, is not sustainable, and the costs of modern farming— measured in fossil-fuel depletion, over-utilized water sources, pollution, and land degradation—will someday need to be paid. At some point, society will need to convert to more sustainable ways of growing food or risk the collapse of the agricultural system. What will be the form of agriculture that can feed a growing human population without spending too much natural capital—for example, whether or not it includes genetically modified organisms—has yet to be determined.

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Food is not the only resource that can put the lid on human population. People need clean water, not only for drinking and bathing, but increasingly for farming and industrial uses. People also need basic sanitation to protect their water supply and prevent disease. While experts like Peter Gleick believe that society can provide clean water to all of the world’s people by directing economic resources at the problem, the population continues to grow. Meanwhile, water resources are already being overused in many locations: Many rivers are already dammed and groundwater is being depleted. Worldwide, water continues to be polluted with sewage, nutrients, and toxic chemicals. Accord- ing to Gleick, people should make water conservation a top priority, and they should develop technologies that use water more efficiently. Since pollution can destroy a useable source of water, much greater caution must be taken with what is released into the environment, and greater efforts should be made to clean up water sources that are already contaminated. The dependence on fossil fuels to provide energy is one of the largest problems that society faces. Petroleum, natural gas, and coal are nonrenewable resources that will eventually run out. As Jeffrey Sachs said at the State of the Planet 06 conference, however, “The good news is we are not going to run out of fossil fuels for centuries. The bad news is we are not going to run out of fossil fuels for centuries.” What Sachs means is that the real costs of fossil-fuel use are not being paid. These energy sources pollute the air, water, and soil; create acid rain; and are the main contributor to global warming. The first and best way to reduce the impacts of fossil fuels is to increase energy efficiency and conservation by changing people’s habits and by developing new technologies. Coal is a major contributor to air pollution and greenhouse-gas emissions, and it is inexpensive and widely available. In the developing nations, especially China, coal is fueling an unprecedented economic expansion. So far, the new coal plants being built in China and the rest of the world are traditional coal-fired plants. Because they are more expensive to build and operate, no one is constructing clean coal plants, which burn the fuel with fewer emissions and are simple to set up so they can capture and sequester carbon,

Conclusion

thereby cutting down on the amount of CO2 released into the atmosphere. It is up to governments to supply incentives for these plants to be built in all nations where new coal plants are being constructed. In addition, the development of sustainable energy sources—solar, wind, geothermal, and others—could decrease carbon emissions so that they are eventually reduced to zero. Current environmental problems are the result of overpopulation. When the human population was low, people could burn wood or coal for fuel, dump wastes in a stream, and clear land for farming with very little impact on the natural environment. Now that these activities are performed by billions of people, the impact of all this activity has become too great. In addition to being caused by overpopulation, environmental problems are also the result of over-consumption, because people in developed countries consume many more resources and produce much more waste than people in poor and developing nations. The impact of the consumer class on the planet is enormous compared with their numbers and, of course, there are many other people in the world who would like to join this group. It is difficult to see what can be done to avert a coming crisis—the human population is growing so fast, some economies are developing at breakneck speed, many people live in abject poverty, and the world’s wealthier people are not likely to cut back on their lifestyles. Some people, however, like Jeffrey Sachs, are optimistic that there are sustainable ways to develop. “We are passing through a bottleneck, but not going over a cliff. We can find marvelous answers to the ecological, health and energy challenges with the positive trends at hand: with the power of science and technology; with the technologies of carbon sequestration and clean energy, of desalinization and improved management of clean water; with the increasing ingenuity in new material sciences and especially in the biological sciences. We are not that far away as it is. We will also arrive, I believe, at more stable human populations, and more urban-based populations where basic human services can be delivered.” As George Musser said in the September 2005 Scientific American, “Humanity is still growing enormously in absolute terms, and

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past success at avoiding Malthusian nightmares is no guarantee of future performance.” The consequences of overpopulation and over-consumption are coming, and the time to move toward a moresustainable future is now. As young people become aware of the environmental problems that are caused by the overuse of resources and overproduction of wastes, they may learn to turn the situation around. A groundswell of young people will make the changes individually, regionally, and globally that are needed, not only so humanity can avoid future Malthusian catastrophes, but also to create a sustainable future for all.

Glossary The alteration of seawater so that it becomes more acidic due to increased atmospheric carbon dioxide that ends up in the ocean and creates carbonic acid.

acidifi cation

Rainfall with a pH of less than 5.0. Acid rain is a type of acid precipitation, which includes acid fog and acid snow.

acid rain

The intensification of agriculture in order to produce more food; techniques include converting more land to farmland, increasing the amount of land that is irrigated, and increasing the use of artificial fertilizers and pesticides.

agricultural intensifi cation

Contamination of the air by particulates and toxic gases in concentrations that can endanger human and environmental health; some air pollutants are greenhouse gases, and some cause global dimming, which is the reduction of solar radiation that reaches the Earth’s surface.

air pollution

A very diverse group that makes up a portion of two different kingdoms; they are not plants, although some look like plants, and all of them photosynthesize. Most are aquatic; most seaweeds are algae.

algae

The raising and harvesting of aquatic plants, fish, and shellfish in a water environment under controlled conditions.

aquaculture aquifer arable

A rock or soil layer that holds useable groundwater. Land that is suitable for farming.

Microscopic single-celled organisms that act as important decomposers.

bacteria

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humans and the natural environment bioaccumulation

The accumulation of toxic substances within living

organisms. Waste that living organisms can decompose into harmless inorganic materials.

biodegradable

Diesel fuel derived from oils found in plants or cooking oil, animal guts, used tires, sewage and plastic bottles.

biodiesel

The number of different species in a given habitat. Tropical rain forests have the highest biodiversity of any ecosystem.

biodiversity

Fuel derived from biomass; wood and manure are natural biofuels. They can also be created from biomass.

biofuel

birthrate

The number of births in a year per 1,000 population.

bushmeat

The meat of wild animals hunted for commercial purposes.

Fish that are unwanted by fishers because they are too small, have too low a value, or are a species that the fisher is not licensed to catch. About 25% of all marine creatures caught are bycatch.

bycatch

Along with human and natural resources, one of the three major types of resources recognized by economists. Refers to the tools and machines made by people that are required for producing goods.

capital

A method of reducing carbon emissions in which carbon dioxide is captured before it is emitted into the air; captured carbon can be sequestered in a reservoir to keep it from entering the atmosphere.

carbon capture

A molecule made of one carbon and two oxygen atoms that is an important component of the atmosphere and an extremely effective greenhouse gas.

carbon dioxide (CO2)

Storage of carbon in one reservoir so that it is no longer part of the carbon cycle; two natural reservoirs for carbon sequestration are forests and oceans.

carbon sequestration

A tax placed on energy sources that emit carbon dioxide into the atmosphere to better pay for the costs of fossil-fuel burning;

carbon tax

Glossary

the tax is intended to inspire conservation and research and development of non-carbon-based technologies. The maximum number of individuals of a particular species an environment can support indefinitely.

carrying capacity

child mortality

A measure of the number of children who die before

age 5. An often fatal disease caused by a bacterium and spread through fecal matter.

cholera

Coal that has undergone gasification to clean it of pollutants before it is burned.

clean coal

A person who is displaced from his home due to climate change; at this time, some Pacific Islanders have been forced to leave their low-lying islands due to rising seas, but many more climate refugees will be created as weather becomes more extreme and sea levels rise higher.

climate refugee

An intestinal disease and major cause of diarrhea caused by cryptosporidium, a single-celled pathogen found in contaminated water.

cryptosporidiosis

A toxic chemical. DDT was a very effective insecticide but was withdrawn from production when its negative effects (and those of its breakdown products) on birds and mammals were realized.

DDT (dichlorodiphenyltrichloroethane)

An ocean region that is hostile to most life, usually due to eutrophication.

dead zone

death rate

The number of deaths per year per 1,000 population.

The conversion of forest area to nonforest area, often agricultural land or human settlements.

deforestation

Characteristics used to separate groups in a population. These characteristics commonly include age, gender, income level, and postal code.

demographics

The nucleic acid that carries hereditary information from parent cell to daughter cell. When a cell divides,

deoxyribonucleic acid (DNA)

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its DNA makes an identical copy of itself that is passed to its daughter. The removal of salts from seawater or brackish water so that it can be made fresh and useful for drinking or agriculture.

desalination

The change of semi-arid landscapes into desert, sometimes by a change in natural rainfall patterns, but often by the misuse of soil or other human activities.

desertification

A process of desalination in which seawater is evaporated and condensed so that the salts are left behind and pure water is available for human use.

distillation

doubling time

The amount of time it takes for a quantity of something

to double. drought

Rainfall that is lower than normal for a region.

A measure of the impact a person or nation has on the environment; ecological footprint is often converted into land equivalents, even though humans make an impact in many more areas.

ecological footprint

The interrelationships of the plants and animals of a region and the raw materials on which they depend.

ecosystem

The positive contributions that ecosystems provide to the functioning of Earth systems; ecosystem services are too numerous to be listed entirely, but they include photosynthesis, water filtration, and soil development.

ecosystem services

Tourism that is environmentally and culturally sensitive and, ideally, sustainable; brings a source of income into the region; and educates the tourists on the political, environmental, and social climate of the region and the country.

ecotourism

A temporary warming of the Pacific Ocean that has implications for global weather patterns; part of the El Niño-Southern Oscillation climate variation.

El Niño

emigration

area.

The movement of organisms, including humans, out of an

Glossary endangered species

An organism that is threatened with extinction.

A compound that interrupts the functions of the endocrine system, often interfering with the sexual development or success of a species; most are estrogens or estrogen mimics.

endocrine disruptor

A person who has been displaced from his home by environmental changes; climate refugees are one category.

environmental refugee

A disease outbreak that affects more people than is normal for that disease or that spreads to regions where it does not normally occur.

epidemic

The movement of sediments from one location to another by water, wind, ice, or gravity.

erosion

Female vertebrate sex hormones that trigger the development of the sex organs and control the reproductive cycle.

estrogen

Liquid biofuel that can be burned in an internal-combustion engine and so can replace gasoline; E85, which is currently on the market, is a mix of 85% ethanol and 15% gasoline.

ethanol

The changes that occur in an aquatic ecosystem when excessive nutrients are released, commonly the depletion of oxygen by bacteria.

eutrophication

evapotranspiration

The loss of water by evaporation from plants.

exponential growth

Growth that is directly proportional to the quantity

itself. A species is extinct if no member survives and reproduces. This can occur in two ways: The species cannot evolve to keep up with a changing environment, or it dies out and its genes are lost.

extinct

Drastic starvation affecting a large number of people within a region.

famine

The total number of live births per 1,000 women of reproductive age 15 to 44.

fertility rate

Level land along a stream that is formed by the deposition of sediments during flooding.

floodplain

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Situation in which people do not have enough food to lead active healthy lives; food insecurity can be temporary, perhaps lasting a season, or chronic and long term.

food insecurity

food security

Situation where people never suffer from hunger nor the

fear of it. Ancient plants that have decayed and been transformed into a useable fuel, especially coal and petroleum. These fuels are really just stored ancient sunshine.

fossil fuels

An energy cell in which chemical energy is converted into electrical energy.

fuel cell

Integrated gasification combined-cycle (IGCC) technology, which cleans coal before it is burned, increasing efficiency and reducing emissions.

gasification

The unit of inheritance that passes a trait from one generation to the next.

gene

The transfer of a gene from one individual or species to another to give that species a desired trait.

genetic engineering

The loss of genetic diversity within a wild population of organisms.

genetic erosion

A strain of plant or animal that has undergone genetic engineering.

genetic modification (GM)

Energy that comes from hot water; this water is heated in a volcano or in the deep Earth.

geothermal energy

The worldwide rising of average global temperature usually referring to the temperature increases that have taken place in the past one-and-a-half centuries.

global warming

Gases that absorb heat radiated from the Earth. They include carbon dioxide, methane, ozone, nitrous oxide, and chlorofluorocarbons.

greenhouse gas

Technological changes in agriculture that occurred after World War II that resulted in enormous increases in food productivity, particularly in grains.

Green Revolution

Glossary

The value of a country’s output in goods and services in a year, measured in U.S. dollars.

gross national product (GNP)

Water found in soil or rock beneath the ground surface.

groundwater

An environment in which an organism lives; contains distinctive features such as climate, resource availability, and predators.

habitat

A metal with high weight, especially one that is toxic to organisms.

heavy metal

Chemical messengers sent out by the endocrine glands to regulate body processes like growth and development.

hormone

With natural resources and capital, one of the three major types of resources recognized by economists; human resources refer to the work, or labor, people do to produce goods.

human resources

Deadly tropical cyclone characterized by high storm surge, abundant rainfall, and intense winds.

hurricane

A fuel-efficient vehicle that runs on a small internalcombustion engine, an electric motor, and a rechargeable battery.

hybrid vehicle

An organic compound composed of hydrogen and carbon; fossil fuels are hydrocarbons.

hydrocarbon

A theoretical system in which people use hydrogenbased energy, such as in fuel cells, to fuel the economy, rather than the carbon-fueled economy of today.

hydrogen economy

The potential energy of falling water; can be harnessed by a water wheel, or by using a waterfall or building a hydroelectric dam.

hydropower

immigration

The movement of organisms, including humans, into an

area. A quota system in which the total fishing quota is divided into percentage shares among the fishers who are using the fishery.

individual fish quotas (IFQ)

A change from manual to mechanized labor in the late eighteenth and early nineteenth centuries; spurred by the

Industrial Revolution

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widespread use of fossil fuels that began around 1850; began in Great Britain and spread to other countries. infant mortality invertebrate

The number of children who die before the age of 1.

An animal without a backbone.

The act of routing water to cropland that does not get enough water naturally; often done by canals, for example.

irrigation

International treaty that went into force in 2004 in which 36 industrialized nations agreed to cut back their CO2 emissions to at least 5% below 1990 levels by 2012.

Kyoto Protocol

A metal, once added to gasoline, paint, pipes and other materials, that is toxic in even tiny doses.

lead

Fatal or chronic disease caused by the protozoan Plasmodium falciparum, which is spread to humans by the Anopheles mosquito.

malaria

A flowering tree that grows in dense forests along tropical shorelines and has its roots submerged for part of the day; mangrove ecosystems provide many important environmental services.

mangrove

Ocean territories where activities are restricted; they vary in size, shape, and level of protection. Unlike marine reserves, most MPAs allow some fishing.

marine protected areas (MPAs)

Marine reserves are more restrictive than marine protected areas. They are “no take,” meaning that no resources of any sort may be harvested.

marine reserves

A mass extinction has occurred if 25% or more of the planet’s species become extinct in a relatively short period of time; a mass extinction opens many ecological niches that need to be filled by other, newer organisms, and so it is a driving force of evolution.

mass extinction

The use of machines to perform labor that was once done by humans or animals.

mechanization

A heavy metal that is released by burning coal, municipal and medical wastes, and by volcanic processes.

mercury

Glossary

A hydrocarbon gas (CH4) that is the major component of natural gas. Methane is also a natural component of the atmosphere and a greenhouse gas.

methane

Prehistoric garbage dumps that hold a wealth of information for modern archeologists.

midden

monoculture natural gas

A farm on which only one species of plant is grown. Gaseous hydrocarbons, primarily methane.

The population growth rate of a defined area that takes into account only births and deaths.

natural growth rate

With human resources and capital, one of the three major types of resources recognized by economists; the raw materials used to produce goods that are found in nature and used with little modification; includes coal, solar radiation, water, and soil.

natural resources

A resource that is not replenished on a time scale that is useful to humans so that when it is gone, there is no more; includes petroleum and many mineral resources.

nonrenewable resource

The energy stored in the nucleus of an atom, which can be released by fission, fusion, or radioactivity.

nuclear energy

A process that splits the nucleus of an atom into smaller pieces accompanied by the release of energy; used in nuclear power plants and nuclear bombs.

nuclear fission

A process in which the nuclei of light elements are combined to form a heavier element accompanied by the release of an enormous amount of energy; fusion reactions are self-sustaining, but so far impossible to contain.

nuclear fusion

Biologically important elements that are critical to growth or to building shells or bones; nitrates, phosphorous, carbonate, and silicate are some nutrients for marine organisms.

nutrients

A renewable energy source that exploits the temperature difference between cold deep waters and warm surface waters.

ocean thermal energy

Sedimentary rock rich in oil that can be mined by using heat and enormous quantities of water.

oil shale

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Resource use that is unsustainable in the long term; the pursuit of excess materialism.

over-consumption

When so many fish are being taken from a fishery that the fish population cannot replenish itself.

overfishing

When the population of a particular species in an area exceeds the area’s carrying capacity; when there is unsustainable use of resources.

overpopulation

A molecule composed of three oxygen atoms and represented as O3. Ozone is a pollutant in the lower atmosphere, but in the upper atmosphere, it protects life on the Earth’s surface from the Sun’s deadly ultraviolet radiation.

ozone

A “hole” in the ozone layer where ozone concentrations are diminished; usually refers to the Antarctic ozone hole.

ozone hole

A disease outbreak, or epidemic, that strikes the entire world or a large portion of it.

pandemic

Organisms that obtain nourishment from a host organism; parasites may or may not harm their host, but they are not beneficial to it.

parasite

Solid or liquid pollutants that are small enough to stay suspended in the air. They are generally nontoxic but can seriously reduce visibility.

particulate

Disease-causing microorganisms including viruses, bacteria, and protozoans.

pathogens

Chemical substances that persist in the environment, bioaccumulate through the food web, and may damage human health and the environment.

persistent organic pollutants (POPs)

A fossil fuel made of hydrocarbons and formed from the transformed bodies of marine organisms.

petroleum

Air pollution that forms when sunlight facilitates the chemical reaction of pollutants such as nitrogen oxides and hydrocarbons.

photochemical smog

The process in which plants use carbon dioxide and water to produce sugar and oxygen. The simplified chemical reaction is 6CO2 + 12H2O + solar energy = C6H12O6 + 6O2 + 6H2O.

photosynthesis

Glossary

Also known as solar cells, photovoltaic cells convert sunlight to usable energy.

photovoltaic cells

Tiny plants (phytoplankton) and animals (zooplankton) that live at the sea surface and form the lower levels of the ocean’s food web.

plankton

A method of agriculture in which several species of animals and/or crops are farmed together.

polyculture

The number of individuals of a particular species living in a defined area.

population

population density

The number of organisms living in a given area or

given volume. population growth rate

A measure of the change in population over a

period of time. An organism that kills and eats other animals for food energy.

predator prey

An animal that is eaten by other animals for food energy.

primary productivity

The food energy created by producers.

A limit placed on a fishery, setting the number of a particular species that are allowed to be taken in a season.

quota

A resource that is replaced in a timescale such that it will not be depleted (within reason); tidal energy and salt are renewable resources.

renewable resource

The fertility rate of women at which they would only replace themselves and their partners; the replacement fertility rate in the industrial nations is around 2.1.

replacement fertility rate

A process of desalination in which saltwater is forced at high pressure through a permeable membrane while leaving the salts behind.

reverse osmosis

The increase in salt content in soil due to its irrigation with brackish water.

salinization

Parasitic disease caused by blood flukes, which need water for part of their life cycle.

schistosomiasis

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A method of changing the frequency of genes in a population in which breeders only breed the organisms that have the traits they desire; until very recently, before the development of genetic engineering, domesticated plants and animals were bred solely by this method, and many growers continue to use it, particularly in locations where genetic engineering is too expensive or is not allowed.

selective breeding

The waste matter that travels through sewers, including the material from the drains of homes, businesses, and industries; it also runs off from the surface ground.

sewage

A process, done mostly in the tropics, where rain forest plants are slashed down and then burned to clear the land for agriculture.

slash-and-burn agriculture

Reduction of a soil’s usefulness due to salinization, acidification, erosion, desertification or other destructive changes; most soil degradation is caused by human activities.

soil degradation

A classification of organisms that includes those that can or do interbreed and produce fertile offspring; members of a species share the same gene pool.

species

The removal of all the land and vegetation in order to access a rock or mineral deposit lying beneath.

strip mining

A level of farming where little more is grown than what is needed to feed the farmer’s family.

subsistence farming

Resource use that does not compromise the current needs for resources or those of future generations for present economic gain.

sustainability

Managing agriculture to be productive without negatively impacting the environment.

sustainable agriculture

Economic development that helps people out of poverty, does not use resources unsustainably, and protects the environment.

sustainable development

A clean, energy-rich flammable gas that is created in gasification plants.

syngas

Glossary

Rocky sands that contain oil; they can be mined by using hot water and caustic soda.

tar sands

threatened species

A species that is likely to become endangered in

the future. A renewable, clean energy source that exploits the rising and falling of the tides.

tidal energy topsoil

The fertile, upper layer of soil.

The population growth rate of a defined region that takes into account births, deaths, immigration, and emigration.

total growth rate

Infection of the mucous membrane of the eyelids caused by the bacterium Chlamydia trachomatis, which is the second leading cause of blindness after cataracts; spread of the disease is easily reduced by washing in clean water.

trachoma

When the value of a nation’s imports exceed the value of its exports; the United States currently has a large trade deficit.

trade deficit

A human population that is growing so slowly or is losing population so that there are not enough young workers to support the elderly.

underpopulation

An increase in the extent or density of an urban area because of migrating rural populations.

urbanization

An animal with a backbone; fish, amphibians, reptiles, birds, and mammals are all vertebrates.

vertebrate

Any liquid waste that comes from homes, businesses, industries, and farms.

wastewater

The cycling of water among Earth’s atmosphere, oceans, and freshwater reservoirs such as glaciers, streams, lakes, and groundwater aquifers.

water cycle

The top level of an aquifer; above this point, pore spaces are filled with air and flowing water; below the water table, the pore spaces become filled with water.

water table

watershed

drains.

A river and all of its tributaries and all of the land that it

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A poorly drained region that is covered all or part of the time with freshwater or saltwater.

wetland

A disease that naturally occurs in animals and can be transferred to humans; HIV/AIDS is thought to be a zoonotic disease.

zoonotic disease

Further Reading Burdick, Alan. Out of Eden: An Odyssey of Ecological Invasion. New York: Farrar, Straus, and Giroux, 2005. Burt, Christopher, and Mark Stroud. Extreme Weather: A Guide and Record Book. New York: W.W. Norton, 2004. Carson, Rachel. Silent Spring. New York: Houghton Mifflin, 1962. Colburn, T., D. Dumanoski, and J.P. Myers. Our Stolen Future: How We Are Threatening Our Fertility, Intelligence and Survival. New York: PLUME, 1997. Davis, Mike. Planet of Slums. New York: Verso, 2006. Diamond, Jared. Collapse: How Societies Choose to Fail or Succeed. New York: Viking Penguin, 2004. Environmental Protection Agency (EPA). “Energy Star.” Available online. URL: http://www.energystar.gov/. Accessed August 22, 2007. _____ “Green vehicle guide.” Available online. URL: http://www.epa.gov/ autoemissions/. Accessed August 22, 2007. Flannery, Tim. The Weather Makers: How Man is Changing Climate and What It Means for Life on Earth. New York: Atlantic Monthly Press, 2006. Fujita, Rod. Heal the Ocean: Solutions for Saving Our Seas. Gabriola Island, Canada: New Society Publishers, 2003. Gore, Al. An Inconvenient Truth: The Planetary Emergency of Global Warming and What We Can Do About It. New York: Rodale, 2006. Hansen, James. “The Threat to the Planet.” New York Review of Books 52 (July 13, 2006). Available online. http://www.nybooks.com/articles/ 19131. Accessed August 22, 2007. Kirby, Alex. “Biodiversity: The Sixth Great Wave.” British Broadcasting Service (BBC). Available online. URL: http://news.bbc.co.uk/1/hi/sci/ tech/3667300.stm. Accessed August 22, 2007. 199

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humans and the natural environment Kite-Powell, Hauke L. “Down on the farm . . . raising fish: Aquaculture offers a sustainable source of seafood, but raises its own set of problems.” Oceanus (September, 2004) Available online. URL: http://www. whoi.edu/oceanus/viewArticle.do?id=2468&archives=true&sortBy= printed. Accessed August 22, 2007. Milius, Susan. “Bushmeat on the menu: Untangling the influences of hunger, wealth, and international commerce.” Science News 167 (Feb 26, 2005): 138–142. National Aeronautics and Space Administration (NASA). “Earth observatory.” Available online. URL: http://earthobservatory.nasa.gov/Topics/ atmosphere.html. Accessed August 22, 2007. Pearce, Fred, and John Gribben. Global Warming (Essential Science Series). New York: Dorling Kindersley Publishing, 2002. Revkin, Andrew. The North Pole Was Here: Puzzles and Perils at the Top of the World. Boston: Kingfisher (Houghton Mifflin), 2006. Safina, Carl. Song for the Blue Ocean: Encounters along the World’s Coasts and Beneath the Seas. New York: Henry Holt, 1997. Tyson, Neil deGrasse. “Knock ’em dead: How does one extinguish life on Earth? Let me count the ways.” Natural History 114 (May 2005): 25–29. Van Dover, Cindy Lee. The Octopus’s Garden: Hydrothermal Vents and Other Mysteries of the Deep Sea. Boston: Addison Wesley, 1996.

Web Sites Alliance to Save Energy

http://www.ase.org/ Helping people save energy is the quickest, cleanest, and cheapest way to a healthier economy, a cleaner environment, and greater energy security. Avoiding Dangerous Climate Change

http://www.stabilisation2005.com/ A symposium and report by the Department for Environment, Food, and Rural Affairs (DEFRA), United Kingdom.

Further Reading Carbonfund.org

http://www.carbonfund.org/site/ A nonprofit organization that offers individuals, businesses and organizations the chance to reduce their climate impact by promoting lowcost carbon reductions and supporting renewable energy, energy efficiency, and reforestation projects. Earthtrends

http://earthtrends.wri.org/ Environmental information by the World Resources Institute. Factmonster

http://www.factmonster.com Online dictionary, encyclopedia, atlas and other helpful aids for finding information on just about anything, from Information Please. Food and Agriculture Organization of the United Nations

http://www.fao.org Information on international agriculture. Global Footprint Network

http://www.footprintnetwork.org/ Advancing the science of sustainability. Hadley Centre for Climate Prediction and Research

http://www.metoffice.com/research/hadleycentre/index.html The foremost climate-research group in the United Kingdom. Intergovernmental Panel on Climate Change

http://www.ipcc.ch/ Access to reports, speeches, graphics, and other materials from the IPCC. Michael Pollan

http://michaelpollan.com/ A writer specializing in the environmental implications of modern food production and in describing alternatives. Pollan’s Web site contains links to many of his articles.

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humans and the natural environment Monterey Bay Aquarium’s Seafood Watch

http://www.montereybayaquarium.org/cr/seafoodwatch.asp Includes regional guides to environmentally sound seafood choices. National Sustainable Agriculture Information Service

http://attra.ncat.org/ Information and news on sustainable agriculture, primarily for farmers. Our Stolen Future

http://www.ourstolenfuture.org/ Website tracking recent developments in the field of endocrine disruption by the authors of the book Our Stolen Future; includes a list of widespread pesticides with endocrine-disrupting effects. Pew Center on Global Climate Change

http://www.pewclimate.org Climate analysis by business leaders, policy makers, scientists, and other experts on sound science; includes the primer Climate Change 101 RealClimate

http://www.realclimate.org Written by working climate scientists for the public and journalists to provide content and context for climate-change stories. Science Daily

http://www.sciencedaily.com/ Science Daily is an online site for current science news in all topics, including oceanography and the environment. SeaWeb

http://www.seaweb.org SeaWeb is a project designed to raise awareness of the world’s oceans and the life within them.

Further Reading State of the Planet 06: Is Sustainable Development Feasible?

http://www.earthinstitute.columbia.edu/sop2006/ Proceedings of a conference that took place March 28–29, 2005, in New York City and was hosted by the Earth Institute of Columbia University. The Fish List

http://www.thefishlist.org Information on whether a fishery is being harvested sustainably can be found in this catalog of recommended and discouraged seafood sources. World Resources Institute

http://earthtrends.wri.org/index.php Earth Trends: Environmental Information.

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Index A acidification, 96, 126 acid rain, 87 Afghanistan, 52 agricultural intensification, 57 agriculture biofuels and, 108 costs of, 121–125 forests and, 158 future of, 140–141 global warming and, 95 loss of land for, 130–131 modernization of, 115–118 population growth and, 118–120 soil degradation and, 126–130 subsistence farming and, 113–115 sustainable, 138–140 water resources and, 28, 44, 46, 55–61, 70–72 AIDS, 14, 16, 24–26 air pollution, 35, 84–87, 91, 157 algae, 38 Algeria, 105 Amazon Basin, 46 Andes Mountains, 93 Antarctic ice sheet, 93 antibiotics, 149, 153 aquaculture, 45, 144, 147–150 arable lands, 114

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Arctic National Wildlife Refuge (ANWR), 82–83 Area de Conservacíon Guanacaste, 163–164 arsenic, 55, 56 Aswan Dam, 124

B bacteria, 38 Bangladesh, 56 bioaccumulation, 60 biodegradation, 38, 53 biodiesel, 107–108 biodiversity, 62, 122–123, 155–156, 160 biofuels, 78, 107–108 birds, 58, 62, 94 birthrate, 4–5, 7, 20–21 Blair, Tony, 96–97 Blue Revolution, 149 Bolivia, 159 boreal forests, 156 Borlaug, Norman, 116, 119–120 Boutros-Ghali, Boutros, 49 Brundtland Report, 18 bubonic plague, 12 buffalo, 28 bushmeat, 150–151 bycatch, 145–146

C Canada, 81 Canadian Standards Association, 163

cancer, 56, 60 cannibalism, 172 cap-and-trade programs, 73, 89 capital resources, 18 carbon capture, 104 carbon dioxide, 87–88 carbon fixation, 38 carbon sequestration, 87, 104–105, 157, 178–179 carbon taxes, 102, 110 caribou, 95 carrying capacity, 16–17, 167–168, 173–175 cattle ranching, 158 Central Valley (California), 66 cereals, 136–137 certification programs, 163 child mortality, 7 Chilean sea bass, 145 China air pollution in, 89, 91 aquaculture in, 148, 150 coal and, 101 controlling population in, 5, 22–23 food production in, 140–141 overhunting in, 151–152 pollution and, 35, 86–87 resource use and, 30–31 soil loss in, 128 water resources of, 46, 55–57, 64–66

Index cholera, 54 Clean Air Acts, 86 Clean Water Act, 57–58, 63, 71 climate, 12. See also global warming climate refugees, 175–178 Club of Rome, 19–20 coal, 35, 78, 81, 101, 104 cod, 145 Cohen, Joel E., 8–10, 14–15 Colorado River, 51 Congo River, 46 conservation, 102, 182 Conservation Reserve Program (CRP), 128 consumer class, 31–32 coral reefs, 94, 98, 160 Costa Rica, 163–164 CRP. See Conservation Reserve Program cryptosporidiosis, 54, 55 Cuyahoga River, 57

D dams, 44–46, 62–63, 105, 117, 124 DDT, 58 dead zones, 58, 124–125, 139 death rate, 4–5, 7 deciduous forests, 156 deforestation, 153, 158–161 demographics, 8–10, 14–15 desalination plants, 67–70 desertification, 128–130 Diamond, Jared, 37, 169, 170, 172, 181 diarrhea, 53–54, 134 diseases, 52–55, 95, 98, 152, 175 distillation, 67–68 DNA (deoxyribonucleic acid), 115 domestication, 115 doubling time, 12–13

drip irrigation, 70, 72 drought, 45, 91, 96–97

E Easter Island, 168–173, 179 ecological footprints, 34, 35 ecosystems, 37, 160, 167–168 ecosystem services, 37–38, 45, 62–63, 157–158, 160 ecotourism, 163 education, population growth and, 7–11, 14, 21–22 efficiency, 70–71, 102–105, 144 EGS. See Enhanced Geothermal Systems Egypt, 49–51, 131 Ehrlich, Paul R., 19, 26, 34, 174–175 electricity, 78 El Niño, 97 emigration, 5, 6–7 emissions credits, 89 employment, population growth and, 14, 21–22 endangered species, 62 endocrine disruptors, 59–60 energy return on investment (EROI), 81, 83 Energy Star program, 103 energy use, 100–110. See also fossil fuels Enhanced Geothermal Systems (EGS), 106 environmental refugees, 175–178 epidemics, 12 EROI. See energy return on investment erosion, 38, 127–128, 160 estrogens, 59 ethanol, 107–108 Ethiopia, 49–51, 134 eutrophication, 58, 124–125, 139 evapotranspiration, 38, 157 evergreen forests, 156

e-waste, 36 exponential growth, 8 extinctions, 160, 167–168

F factory farms, 152–154 famines, 11–12, 13, 95, 133–134, 180–181 farming. See agriculture feedlots, 153 fertility, endocrine disruptors and, 59 fertility rates, 6, 8, 22–23 fertilizers, 58, 117–118, 124–125, 138 fir trees, 156 fish, 59, 62, 94, 143–147 fish farming, 45, 144, 147–150 fission, 107 flooding, 91–92, 94, 96 flood irrigation, 70 floodplains, 114, 130 Florida, 58, 69–70 fluorine, 55 food insecurity, 132–134, 136 food production, increasing, 136–138 food security, 124–125, 135–136 food webs, 60 footprints, ecological, 34, 35 Forestry Stewardship Council (FSC), 163 forests. See also deforestation management of, 161–162 sustainable forestry and, 155, 162–164 types of, 155–156 uses of, 157–158 fossil fuels. See also global warming agriculture and, 117, 123–124 air pollution and, 84–87 current use of, 79–80 diminishing supply of, 80–82

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humans and the natural environment fossil fuels (continued) factory farms and, 153 future of, 182–183 global warming and, 36 Industrial Revolution and, 29 as nonrenewable resource, 18 overview of, 77–78 politics and, 82–83 freshwater stress, 65 FSC. See Forestry Stewardship Council fuel, 157 fuel cells, 108–109 fusion, 107

G gangrene, 56 gasification, 104 gasoline additives, 58 genetic erosion, 122 genetic modification (GM) aquaculture and, 149 criticisms of, 123 future food needs and, 137, 181 genetic erosion and, 122 overview of, 116–117 genetics, agriculture and, 114–115 genocide, 181 Georges Bank, 145 geothermal energy, 106 glaciers, 43, 66, 93 Gleick, Peter, 66–67, 68–69, 70–73, 182 Glen Canyon Dam, 62 global warming crop yields and, 141 deforestation and, 161 efficiency improvement and, 102–105 environmental refugees and, 175–178 fossil fuels and, 36 future of, 95–99

humans and, 94–95 ice, snow, water and, 93–94 Kyoto Protocol and, 89–90 organisms and, 94 overview of, 87–89, 91 technological advances and, 105–110 water resources and, 66 weather pattern changes and, 91–92 GM. See genetic modification Goodall, Jane, 151 grazing, 140, 152–153, 158 Great Barrier Reef, 147 Great Leap Forward, 5, 22 greenhouse gases, 36 Greenland ice sheet, 12, 93 Green Revolution, 19, 115–118, 121–125, 137–138 gross domestic product (GDP), 31, 35, 115 gross national product (GNP), 25–26, 71, 103–104 groundwater, 44–47, 58, 157 Guanacaste, 163–164 Gulf of Mexico dead zone, 124–125

H habitat loss, 97, 168 habitats, wetlands as, 45 Hansen, James E., 87 hard solutions, 64, 66–67, 70 heat waves, 91, 96 heavy metals, 60, 85 herbicides, 118 Himalaya Mountains, 66 HIV, 24, 152, 178. See also AIDS hog farming, 153 Homer-Dixon, Thomas, 81, 109 hormones, 59, 153 house sizes, increasing, 32–33 human resources, 18 hunter-gatherers, 27–28

hunting, 150–152 hurricanes, 92, 97, 177 hybrid vehicles, 103 hydrocarbons, 84 hydrogen economy, 108–109 hydrologic cycle, 38 hydropower, 44–45, 105

I ice sheets, 93 IFQs. See individual fish quotas IGCC. See gasification Imhoff, Marc, 131 immigration, 5, 6–7 individual fish quotas (IFQs), 146 Industrial Revolution, 29, 36 industry, 44–45, 55–61, 71–72, 158 infanticide, 21, 23 infant mortality, 7 insecticides, 58, 118 insects, 123 insurance, 98 integrated gasification combined cycles. See gasification Inuit, 21, 95 invertebrates, 58 iodine, 134 Irish Potato Famine, 12 irrigation agriculture and, 28, 46, 114, 117, 124 efficiency in, 70–72 global warming and, 95 salinization and, 126

J Japan, 34

K Koonin, Steven E., 80–81, 100 Kuwait, 67 Kyoto Protocol, 89–90

Index L landfills, 36 lead, 85 Limits of Growth, The (Club of Rome), 19–20 Little Ice Age, 12 livestock, 152–154, 158 logging, 34, 159, 162. See also deforestation Lubchenco, Jane, 149

M magnetite, 56 malaria, 98 malnutrition, 134, 137 Malthus, Thomas, 17–19, 26, 180–181, 184 mangroves, 149–150 Manning, Richard, 121 marine protected areas (MPAs), 146 marine reserves, 146–147 mass extinctions, 168 Maya civilization, 47–49 McGregor, James, 35 Meadows, Donatella, 19–20 meat consumption, 140 mechanization, 28–29, 117, 122–123, 153–154 Mekong River, 147 mercury, 60 Mesopotamia, 114 methane, 88, 153 Mexico City, 47, 70, 86–87 middens, 169–170 migration, 94, 95 mining, 78, 158 Mississippi River, 63, 124–125 moai. See Easter Island Monaco, 7 monocultures, 118, 122–123, 127, 161 Monterey Bay Aquarium, 147 moratoriums, 145 mulching, 128

multinational corporations, 34, 36 Musser, George, 183–184

N Native Americans, 28 natural gas, 78, 81 natural growth rate, 4–5 natural resources, overview of, 18 Nile River, 49–51, 124, 131 nitric acid, 87 nitrobenzene, 55–56 nitrogen fertilizers, 118 nonrenewable resources, 18 Norway, 105 nuclear energy, 107, 109 nurseries, 45 nutrients, 114, 160–161

O ocean acidification, 98 ocean thermal energy, 107 Ogallala Aquifer, 47 oil shale, 78, 81, 87 orphans, 26 overconsumption, results of, 27, 173–175 overfishing, 143–147 overhunting, 150–152 overpopulation carrying capacity and, 16–17 current crisis of, 167–168 debate surrounding, 17–20 decreasing population growth rate and, 22–23 Easter Island and, 168–173 future of, 175–178 overview of, 183 population control and, 20–21 results of, 173–175 sustainable development and, 178–179

ozone, 85, 86 ozone hole, 86

P Pacific Institute, 68–69 pandemics, 12, 13–14. See also AIDS pangolin, 151–152 parasites, 54 particulates, 84 pastoralists, 123 pathogens, 52–55, 95, 98 Patzek, Tad, 108 Persian Gulf, 82 persistent organic pollutants (POPs), 60, 61 pesticides, 60, 123, 125 phosphates, 118, 124 photochemical smog, 84 photosynthesis, 37–38 photovoltaic cells, 105, 109 phthalates, 59–60 Pimentel, David, 108 piñon bark beetle, 94 plague, 12 plankton, 78, 94 plantations, 161 politics, 82–83 Pollan, Michael, 139 pollination, 38, 122–123 pollution agriculture and, 118 air, 35, 84–87, 91, 157 aquaculture and, 149–150 factory farms and, 154 resource use and, 35–36 water, 35, 52–63 polycultures, 114, 138, 150, 162 population, 3–4, 11–15. See also overpopulation Population Bomb, The (Ehrlich), 19 population control, 20–21 population demographics, 8–10, 14–15 population density, 7, 11

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humans and the natural environment population growth rate. See also overpopulation age structure and, 5–7 agriculture and, 118–120 decreasing, 20, 22–23 defined, 4–5 factors affecting, 7–11, 14, 21–22 sustainable development and, 178 urbanization and, 10 poverty, 30–32, 46, 134 predators, 17 prey, 17 primary productivity, 124 pyramids, 47–48

Q quotas, 145, 146

R rain forests, 156, 159–160 Rapa Nui. See Easter Island Rapley, Chris, 110 recycling, 163 redwood trees, 156 reforestation, 161 refugees, 175 renewable resources, 18 replacement fertility rate, 6 resource use current, 30–34 ecosystem services and, 37–38 evolution of, 27–29 overconsumption and, 27, 173–175 sustainable development and, 36–37 waste, pollution and, 35–36 reverse osmosis, 68–70 Rockström, Johan, 140 Romm, Joseph, 81–82, 101, 109 Rule of 70, 12–13 Rwanda, 181

S Sachs, Jeffrey, 39, 168, 179, 182, 183 salinization, 126 salts, 55, 68–69 SARS, 152 Saudi Arabia, 67–68 schistosomiasis, 54 sea ice, 93, 95 sea levels, rising, 94, 98 sea surface temperatures, 97 selective breeding, 114–115 sequestration, 87, 104–105, 157, 178–179 Serageldin, Ismail, 118 severe acute respiratory syndrome (SARS), 152 sewage, 53 shellfish, 143–144, 147 Shishmaref village, 95 Singapore, 23 Siwan people, 20–21 slash-and-burn farming, 126, 161 slums, 175–178 smog, 84 smuggling, e-waste and, 36 snow pack size, 94 soft solutions, 64, 66–67, 70–71 soils, 114, 126–130, 160 solar cells, 105, 109 Songhua River, 55–56 soybeans, 159 species, defined, 3 speed limit reduction, 103 State of World Fisheries and Aquaculture, The (SOFIA), 144 statues. See Easter Island strip cropping, 128 strip mining, 78 subsistence farming, 113–115, 141 Sudan, 49–51 sulfuric acid, 87

sustainability aquaculture and, 149 ecological footprints and, 34 groundwater use and, 47 overconsumption and, 27, 173–175 overview of, 18 resource use and, 36–37 water resource preservation and, 66–73 sustainable agriculture, 138–140 sustainable development, 37, 178–179 sustainable forestry, 155, 162–164 Sustainable Forestry Initiative, 163 syngas, 104

T Tampa Bay Plant, 69–70 tar sands, 78, 81–82, 87 Taxol, 160 temperate forests, 156, 159 threatened species, 62 Three Gorges Dam, 67 tidal energy, 106 Tierras Bakas project, 159 total growth rate, 5 trade deficit, 82 transportation, 29, 80, 102–103 tree farms, 161 tropical rain forests, 156, 159–160

U UNESCO, 49 urbanization, 10, 15, 130–131, 157

V Venezuela, 81 vertebrates, 160

Index W waste, 35–36 wastewater, 53 water cycle, 38 water pollution, 35, 52–63 water resources agriculture and, 123–124 ecosystem services and, 62–63 factory farms and, 153–154

future need for, 64–66 preservation of, 66–73, 182 sharing of limited, 49–51 sources of, 43–44 uses of, 44–49 watersheds, 72 water stress, 65 wealth, 30–33, 46 weather, 91–92, 96 wetlands, 28, 45, 62–63, 114

wheat, 116, 119 Wilson, E.O., 168 wind energy, 105–106

Y Yangtze River, 67

Z Zedong, Mao, 22 zoonotic diseases, 152

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About the Author DANA DESONIE, Ph.D., has written about earth, ocean, space, life, and environmental sciences for more than a decade. Her work has appeared in educational lessons, textbooks, and magazines, and on radio and the Web. Her 1996 book, Cosmic Collisions, described the importance of asteroids and comets in Earth history and the possible consequences of a future asteroid collision with the planet. Before becoming a science writer, she received a doctorate in oceanography, spending weeks at a time at sea, mostly in the tropics, and one amazing day at the bottom of the Pacific in the research submersible Alvin. She now resides in Phoenix, Arizona, with her neuroscientist husband, Miles Orchinik, and their two children.

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Humans and the Natural Environment: The Future of Our Planet

Humans and the Natural Environment: The Future of Our Planet (Our Fragile Planet)

The Future of Life and the Future of our Civilization

Measuring the natural environment

Economics of the Environment and Natural Resources

Africa Environment Outlook: Our Environment, Our Wealth

The precautionary principle: protecting public health, the environment and the future of our children

Human Well-Being and the Natural Environment

Representing Modeling and Visualizing the Natural Environment

Future Energy: Improved, Sustainable and Clean Options for our Planet

Identity and the Natural Environment: The Psychological Significance of Nature

The Economics of the Environment and Natural Resources

Night Of The Humans

Understanding Our Environment

Our changing planet

Our Haunted Planet

The Global Carbon Cycle: Integrating Humans, Climate, and the Natural World (Scientific Committee on Problems of the Environment (SCOPE) Series)

Business Ethics And The Natural Environment (Foundations of Business Ethics)

The Future of Progress: Reflections on Environment and Development

Philosophy and the Natural Environment (Royal Institute of Philosophy Supplements)

Our Natural History: The Lessons of Lewis and Clark

The Human Impact on the Natural Environment: Past, Present, and Future

Ocean Outpost: The Future of Humans Living Underwater

Our Planet - The Earth (Science for Everyone)

Our Energy Future: Resources, Alternatives and the Environment (Wiley Survival Guides in Engineering and Science)

The God Code: The Secret of Our Past, the Promise of Our Future

Six Degrees : Our Future on a Hotter Planet

Six Degrees Our Future on a Hotter Planet

Six Degrees Our Future on a Hotter Planet

Illuminating the Hidden Planet: The Future of Seafloor Observatory Science

Humans and the Natural Environment: The Future of Our Planet