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N E EARTH OUR CHANGING GIOBAI ENVIRONMENT ONE FUTURE by Cheryl Simon Silver wit Rum S. Decries for the National Academy of Sciences NATIONAL ACADEMY PRESS Washington, D.C. 1990
National Academy Press. 2101 Constitution Avenue, N.W. · Washington, D.C. 20418 NOTICE: The project that is the subject of this report was approved by the Governing Board of the National Research Council, whose members are drawn from the councils of the National Academy of Sciences, the National Academy of Engineering, and the Institute of Medicine. This report has been reviewed by a group other than the authors according to procedures approved by a Report Review Committee consisting of members of the National Academy of Sciences, the National Academy of Engineering, and the Institute of Medicine. Support for this project was provided by The Business Roundtable, the Arthur L. Day Fund of the National Academy of Sciences, the Geraldine R. Dodge Foundation, the Department of Energy, the Environmental Protection Agency, the National Aeronautics and Space Administration, the National Oceanic and Atmospheric Administration, the National Science Foundation, the Tinker Foundation, and the U.S. Committee for Man and the Biosphere. The Rockefeller Foundation contributed to the support of the teleconferenc- ing. This book is printed on acid-free recycled paper. W Library of Congress Cataloging-in-Publication Data Silver, Cheryl Simon. One earth, one future: our changing global environment / by Cheryl Simon Silver with Ruth S. DeFries for the National Academy of ~ . sciences. p. cm. ISBN 0-309-04141-4 (case); ISBN 0-309-04632-7 (paper) 1. Man Influence on nature. 2. Pollution. 3. Global warming. 4. Environmental policy. I. DeFries, Ruth S. II. National Academy of Sciences (U.S.) III. Title. GF75.S55 1990 363.7~c20 CIP Copyright (if) 1990 by the National Academy of Sciences No part of this book may be reproduced by any mechanical, photographic, or electronic process, or in the form of a phonographic recording, nor may it be stored in a retrieval system, transmitted, or otherwise copied for public or private use, without written permission from the publisher, except for the purposes of official use by the United States Government. Printed in the United States of America 90-5939 Cover photograph: ROUSSEAU, Henri The Dream. 1910. Oil on canvas, 6'8 1/2" x 9'9 1/2". Collection, The Museum of Modern Art, York New York. Gift of Nelson A. Rockefeller. Photograph ~ The Museum of Modern Art, New York First Printing, November 1990 Second Printing,, July 1992 Third Printing, November 1992 Fourth Printing, January 1994 Fifth Printing, January 1996
Preface Human activities are transforming the global environment, and these global changes have many faces: ozone depletion, tropical deforestation, acid deposition, and increased atmo- spheric concentrations of gases that trap heat and may warm the global cInnate. For many of these troubling transformations, data and analyses are fragmentary, scientific understanding is incomplete, and long-term implications are unknown. Yet, even against a continuing background of uncertainty, it is abundantly clear that human activities burning fossil fuels, emitting pollu- tants from industry, and clearing forests that are the habitats for plant and animal species, for exampIc now match or even sur- pass natural processes as agents of change in the planetary envi- ronment. Understanding the nature and possible consequences of global change is an urgent challenge to the natural sciences, social sciences, ant} engineering, and to the world community of nations and their citizens. Global environmental change is interwoven with a com- plex web of social, economic, political, and scientific implica- tions. Recent natural fluctuations in weather and climate, while not necessarily attributable to cInnate change due to human ac · · -
1V PREFACE tivities, nevertheless illustrate the magnitude and broad scope of environmental impacts on our intricately intertwined global economy. Widespread droughts in the early 1970s set the stage for major worldwide swings in grain prices. Persistent droughts in Africa have caused unspeakable suffering for millions of peo- ple. Damage caused as pollutants travel across national bound- aries and result in acid deposition has created major political tensions in North America. The diverse faces of global environmental change are linked both scientifically and politically. Scientifically, the ability to predict future changes in the environment requires an under- standing of the physical, chemical, biological, and social pro- cesses that govern the earth, and of the interaction of these pro- cesses throughout the earth system. Politically, policy options to adclress these problems highlight the need for coordinated international policies relating to energy, technology, land use, and economic development. Thus difficult policy decisions must be made on the basis of judgments between dunly perceived future risks and possible economic or other consequences that may be more immediate. While these decisions must be based on the best Information that science has to offer, scientists are no better qualified than other individuals to hammer out these difficult judgments. It is important that the public also become informed and involved in making these choices and shaping the necessary policy deci- s~ons. It was with a realization of the indispensable role of an in- formed public that the 1989 Forum on Global Change and Our Common Future was conceived. The forum's goal was to pro- mote and enhance understanding and dialogue on a broad range of issues related to global environmental change and the dy- namic interactions among the physical, chemical, biological, and social systems that make the earth's environment so uniquely hospitable to life. The presentations and discussions during the eventful three days of the forum provided the stimulus and the basis for this book. The forum is but one of many activities related to these
PREFACE V complex issues. For example, in the fall of 1988 the National Academy of Sciences, National Academy of Engineering, and Institute of Medicine prepared recommendations on global en- vironmental change for then President-elect George Bush. That document, which may be found in Appendix D, is the cur- rent position of the Academies and the Institute in this area. In addition, at the request of Congress, the U.S. Environmental Protection Agency commissioned a study on policy implications of greenhouse warming by the Committee on Science, Engineer- ing, and Public Policy of the councils of the two Academies and the Institute. The report of that panel, which is expected to be available by the end of 1990, will be the next major statement of the Academies and Institute in this area. Within this context, this book is intended as a contribution to the active global dialogue that will shape the future of our species and our planet. fry FRANK PRESS President National Academy of Sciences
The National Academy of Sciences is a private, nonprofit, self-perpetu- ating society of distinguished scholars engaged in scientific and engineering research, dedicated to the furtherance of science and technology and to their use for the general welfare. Upon the authority of the charter granted to it by the Congress in 1863, the Academy has a mandate that requires it to advise the federal government on scientific and technical matters. Dr. Frank Press is president of the National Academy of Sciences. The National Academy of Engineering was established in 1964, under the charter of the National Academy of Sciences, as a parallel organization of outstanding engineers. It is autonomous in its administration and in the selection of its members, sharing with the National Academy of Sciences the responsibility for advising the federal government. The National Academy of Engineering also sponsors engineering programs aimed at meeting na- tional needs, encourages education and research, and recogruzes the superior achievements of engineers. Dr. Robert M. White is president of the National Academy of Engineering. The Institute of Medicine was established in 1970 by the National Academy of Sciences to secure the services of eminent members of appro- priate professions in the examination of policy matters pertaining to the health of the public. The Institute acts under the responsibility given to the National Academy of Sciences by its congressional charter to be an adviser to the federal government and, upon its own initiative, to identify issues of medical care, research, and education. Dr. Samuel O. Thier is president of the Institute of Medicine.
Acknowledgments Many people contributed to the development of this book. First and foremost, the Forum on Global Change and Our Com- mon Future, on which this book is based, was originally con- ceived by Harold Mooney of Stanford University, chairman of the National Research Council's Committee on Global Change (see Appendix C). Tom Malone, of St. Joseph College, and many others were instrumental in developing and organizing the fo- rum. John Perry, of the National Research Council, was particu- larly crucial in the development of both the forum and this book and provided helpful guidance along the way. We gratefully acknowledge the participation of the speakers at the forum (see Appendix By, whose papers provided the basis for this book. Informal comments on technical aspects of each of the chapters of this book were provided by the following experts in the relevant fields, and we thank them for their time and thoughtful critiques: INTRODUCTION William Clark, Harvard University; Robert Kates, Brown University · e V11
· · - V111 ACKNOWLEDGMENTS A NEW SCIENCE OF THE EARTH Kevin Burke, Lunar and Planetary Institute; S. Ichtiaque Rasool, National Aeronautics and Space Administration; Myron F. Uman, National Research Council LESSONS FROM THE GEOLOGIC PAST Kevin Burke, Lunar and Planetary Institute; John Kutzbach, University of Wisconsin; S. Ichtiaque Rasool, National Aeronautics and Space Administration; Myron F. Uman, National Research Council SYSTEM INTERACTIONS: ATMOSPHERE, OCEANS, LAND, AND HUMANS Kevin Burke, Lunar and Planetary Institute; S. Ichtiaque Rasool, National Aeronautics and Space Administration; Myron F. Uman, National Research Council HUMANITY: AN AGENT OF GLOBAL ENVIRONMENTAL CHANGE Jesse Ausubel, Rockefeller University; William Clark, Harvard University; Robert Kates, Brown University; B. L. Turner II, Clark University GLOBAL WARMING Robert Dickinson, National Center for Atmospheric Research; Jerry Mahlman, National Oceanic and Atmospheric Administration; Stephen H. Schneider, National Center for Atmospheric Research FOOD, WATER, AND CHANGING CLIMATE Norman Rosenberg, Resources for the Future; Cynthia Rosenzweig, Columbia University COASTLINES AND RISING SEAS James Broadus, Woods Hole Oceanographic Institution; Mark Meter, University of Colorado THE OZONE LAYER AND ULTRAVIOLET RADIATION Dan Albritton, National Oceanic and Atmospheric Adm~rustration; F. Sherwood Rowland, University of California at Irvine; Susan Solomon, National Oceanic and Atmospheric Administration VANISHING FORESTS AND VANISHING SPECIES Judith Gradwohl, Smithsonian Institution; Robert Peters, World Wildlife Fund; Jeffrey Richey, University of Washington
ACKNOWLEDGMENTS ix LAKES, FORESTS, AND ACID DEPOSITION lames Galloway, University of Virginia; Mark Haag, Department of Justice; Arthur Johnson, University of Pennsylvania; David Schindler, University of Alberta, Edmonton, Canada Roseanne Price, of the National Research Council, edited the draft and provided many helpful comments on the content. We gratefully acknowledge the contributions of all of these people, without whom this book would not have been possible. CHERYL SIMON SILVER RUTH S. DeFRIES
Contents 1 INTRODUCTION THE EARTH AS A SYSTEM A NEW SCIENCE OF THE EARTH LESSONS FROM THE GEOLOGIC PAST Formation of the Ozone Shield, 21 Pangaea, 21 The Ice Ages, 24 The Current Warm Phase, 27 SYSTEM INTERACTIONS: ATMOSPHERE, OCEANS, LAND, AND HUMANS Atmosphere, 32 Oceans, 37 Land, 40 The Water Cycle, 43 Human Interactions, 45 5 HUMANS: AN AGENTr OF GLOBAL ENVIRONMENTAL CHANGE Population, Affluence, and Technology: How Humans Change the Environment, 50 x 1 15 20 31 49
CONTENTS Changing He Face of the Earth: Agriculture and Industry, 56 lithe Future, 59 THE FACES OF GLOBAL ENVIRONMENTAL CHANGE 6 GLOBAL WARMING Greenhouse Gases, 64 The Climate's Response to Greenhouse Gases, 67 Do We Know Enough to Act? 76 FOOD, WATER, AND CHANGING CLIMATE lithe Global Harvest, 79 The Effect of Global Warming on Food Production, 82 Water Supply, Irrigation, and the Hydrologic Cycle, 85 Exploring Avenues for Adaptation, 87 8 COASTLINES AND RISING SEAS The Human Costs of Rising Sea Level, 92 The Plight of the Deltas, 97 Preparing for Rising Seas, 100 9 THE OZONE LAYER AND ULTRAVIOLET RADIATION Chemistry of the Ozone Layer, 104 Studying the Antarctic Ozone Hole, 107 Ozone Depletion in Other Latitudes, 111 Effects on Life, 113 Nations Joining to Protect the Ozone Layer, 114 10 VANISHING FORESTS AND VANISHING SPECIES Why Are the Forests Disappearing? 118 Soil Erosion, Rain Machines, and Carbon, 120 Vanishing Species, 123 Protecting the Forest Resources, 130 11 LAKES, FORESTS, AND ACID DEPOSITION lithe Acidification Process, 133 Lakes, 135 Forests, 138 Buildings and Monuments, 141 Controlling Acid Deposition, 142 X1 63 78 90 116 131
xii INDEX CONTENTS AFI ERWORD GLOBAL CHANGE AND OUR COMMON FIJTU~, by Gro Harlem Brundlland APPENDIXES A. Selected Reading B. Forum on Global Change and Our Common Future: Agenda and Speakers Committee on Global Change and Oversight Committee Members D. Letter on Global Environmental Change to President-Elect George Bush from the National Academy of Sciences, the National Academy of Engineering, and the Institute of Medicine 147 161 163 167 169 187