RESTORING THE QUALITY OF OUR ENVIRON MEN Report of The Environmental Pollution Panel President?s Science Advisory Committee THE WHITE HOUSE NOVEMBER 1965 THE. WHITE HOUSE WASHINGTON November 5, 1965 Ours is a nation of affluence. But the technolOgy that has permitted our affluence spews out vast quantities of wastes and spent products that pollute our air, poison our waters, and even impair our ability to feed ourselves. At the same time, we have crowded together into dense metropolitan areas where concentration of wastes intensifies the problem. Pollution now is one of the most pervasive problems of our society. With our numbers increasing, and with our in- creasing urbanization and industrialization, the flow of pollutants to our air, soils and waters is increasing. This increase is so rapid that our present efforts in managing pollution are barely enough to stay even, surely not enough to make the impr0vements that are needed. Looking ahead to the increasing challenges of pollution as our population grows and our lives become more urbanized and industrialized, we will need increased basic research in a variety of specific areas, including soil pollution and the effects . of air pollutants on man. We must give highest priority of all to increasing the numbers and quality of the scientists and engi- neers working on problems related to the control and management of pollution. A: I am asking the appropriate Departments and Agencies to consider the recommendations and report to me on the ways in which we can move to cope with the problems cited in the Report. Because of its general interest, I am releasing the report for publication. For sale by the Superintendent of Documents, U.S. Government Printing Of?ce Washington, 110., 20402 Price 31.25 cents SCIENCE ADVISORY COMMITTEE DONALD F. HORNIG, Chairman, Special Assistant to the President for Science and Technology - HERBERT F. YORK, Jr., Vice Chairman, Professor of Phys1cs, Umvers1ty of California, San Diego I Lewis M. Branscomb, Chairman, Joint Inst1tute for Laboratory Astro- physics, Boulder - . . . Melvin Calvin, Professor of Chemistry, of California, Berkeley Richard L. Garwin, Thomas Watson Research Center, International Business Machines Corporation, Yorktown Heights - I Marvin L. Goldberger, Professor of Physics, Princeton . I Philip Handler, Chairman, Department of Biochemistry, Duke Umversity Medical Center . Franklin A. Long, Vice President for Research and Advanced Studles, Cor? nell University, Ithaca Gordon J. F. MacDonald, Chairman, Department of Planetary and Space Physics, Institute of Geophysics and Planetary Physics, Un1ver51ty of Cali? fornia, Los Angeles William D. McElroy, Chairman, Department of Biology, The Johns Hop- kins University - . George E. Pake, Provost, Washington Un1vers1ty, St. L0u1s. . I John R. Pierce, Executive Director, Researcthommunications Seiences Division, Bell Telephone Laboratories . Kenneth S. Pitzer, President, Rice . . Edward M. Purcell, Professor of Physics, Harvard University Frederick Seitz, President, National Academy of Sciences IV ENVIRONMENTAL POLLUTION PANEL JOHN W. TUKEY, Chairman, Professor of Mathematics, Princeton Uni- versity, and Associate Executive Director, Research?Communications Sciences Division, Bell Telephone Laboratories Martin Alexander, Associate Professor of Soil Science, New York State Col- lege of Agriculture, Cornell University, Ithaca H. Stanley Bennett, Dean, Division of Biological Sciences, University of Chicago Nyle C. Brady, Director of Of?ce of Science and Education, US. Depart ment of Agriculture (until August 31, 1965), Director of the Cornell University Experiment Station, Director of Research, New York State College of Agriculture, Cornell University, Ithaca John C. Calhoun, Jr., Science Advisor to the Secretary of the Interior (until February 5, 1965), Vice President for Programs, Texas A University System, College Station John C. Geyer, Chairman, Department of Sanitary Engineering and Water Resources, The Johns Hopkins University, Baltimore Aarie J. Haagen?Smit, Professor of Biochemistry, California Institute of Technology, Pasadena Norman Hackerman, Vice Chancellor for Academic Affairs, University of Texas, Austin James B. Hartgering, Director of Research and Education, American Hos~ pital Association, Chicago David Pimentel, Head, Department of Entomology and Limnology, New York State College of Agriculture, Cornell University, Ithaca Roger Revelle, Director, Center for Population Studies, Harvard University Louis H. Roddis, President, Electric Company, Johnstown William H. Stewart, (member until June, 1965) Of?ce of the Secretary, US. Department of Health, Education, and Welfare, Washington James L. Whittenberger, Professor of Public Health, Harvard School of Public Health - John L. Buckley, Sta?, Technical Assistant, Of?ce of Science and Tech? nology, Washington Contents Page Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . IX 1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 The Effects of Pollution . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 Health Effects . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 Excessive air pollution for short periods . . . . . . . . . . . . . . . . . 3 3 Prolonged exposure to ordinary urban air pollution . . . . . . . 3 Water-borne pollutants and health . . . . . . . . . . . . . . . . . . . . . 4 Pesticides and human health . . . . . . . . . . . . . . . . . . . . . . . . . . 4 Effects on Other Living Organisms . . . . . . . . . . . . . . . . . . . . . . . . 5 Why do we careKinds of effects on organisms other than man . . . . . . . . . . . . 5 Impairment of Water and Soil Resources . . . . . . . . . . . . . . . . . . . 7 Excess fertility in waters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 Soil pollution . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 Polluting Effects of Detergents . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 Deterioration of Materials and Urban Environments . . . . . . . . . 9 Climatic Effects of Pollution . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 The Sources of Pollution . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 Municipal and industrial sewage . . . . . . . . . . . . . . . . . . . . . . . . . . 10 Animal wastes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 Urban solid wastes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 Mining wastes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 Consumer goods wastes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 Unintentional Releases . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 In Which Directions Should Recommendations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16 A. Principles . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16 B. Actions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17 C. Coordination and Systems Studies . . . . . . . . . . . . . . . . . . . . . . 23 D. Baseline Measurement Programs . . . . . . . . . . . . . . . . . . . . . . . 25 E. Development and Demonstration . . . . . . . . . . . . . . . . . . . . . . 26 F. Research . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29 G. Manpower . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33 H. Incompleteness of RecommendationsAppendixes: X1. Challenging Tasks for the Men and Women Who Can Improve the Quality of Our Environment . . . . . . . . . . . . 39 X2. Organizational Questions . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48 X3. A ?General? Index of Chemical Pollution . . . . . . . . . . . . . . 57 X4. Standards Development . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59 X5. Metropolitan Problems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62 X6. Air Problems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 66 X7. Water Quality . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 70 VII CONTENTS Subpanel Reports Y1. Soil Contamination . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Y2. Health Effects of Environmental Pollution . . . . . . . . . . . . . . Y3. Benchmark Surveillance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Y4. Atmospheric Carbon Dioxide . . . . . . . . . . . . . . . . . . . . . . . . . Y5. Solid Wastes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Y6. Combined Sewers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Y7. Effects of Chlorinating Wastes . . . . . . . . . . . . . . . . . . . . . . . . Y8. Agricultural Wastes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Y9. Aquatic BloomsY10. Effects of Pollutants on Living Organisrns Other Than Man . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Yli. Improved Pest Control Practices . . . . . . . . . . . . . . . . . . . . . . Index . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 293 Acknowledgements The study was conducted under the general supervision of Colin M. MacLeod, Deputy Director, Of?ce of Science and Technology. The Panel drew on scientists and engineers from Within the Federal Gov? ernment, from state governments, universities and industry to form sub- panels of experts, each of which explored a different problem. These busy men put in, on the average, several weeks of their time talking to scientists, studying and evaluating information published and unpublished, and writing reports. The reports are included as the Appendixes. The members of the subpanels are listed on the following pages. SOIL CONTAMINATION H. Stanley Bennett, Chairman H. L. Lucas Dean, Division of Biologicai Sciences Professor and Director of Biomathematics University of Chicago Training Program Institute of Statistics Martin Alexand?r North Carolina State University, Raleigh Associate Professor of Soil Science New York State Coilege of Agriculture Thomas J. Sheets, ta?' Cornell University, Ithaca Crops Research Division- Agricultural Research Service Sterling 3- HendriCkS US. Department of Agriculture Soil and Water Conservation Research Beltsville, Maryland DiviSion Prescnt address) Associate Professor of Agricultural Research Service Entomology and Crop Science US. Department Of Agriculture North Carolina State University, Raleigh Beitsville, Maryland HEALTH EFFECTS OF ENVIRONMENTAL POLLUTION Lincoln E. Moses Executive Head Department of Statistics Stanford University James L. Whittenberger, Chairman Professor of Public Health Harvard School of Public HeaIth Aarie J. Haagen-Smit Professor of Biochemistry William H. Stewart (member until California Institute of Technology, June 1965) Pasadena Office of the Secretary US. Department of Heaith, Education, and Welfare, Washington RESTORING THE QUALITY or OUR ENVIRONMENT ACKNOWLEDGEMENTS XI Aarie J. Haagen-Smit Geor J. hiasiach H. 11, s: . . John R. Bang, ruce. ubl Dill? Center Professor of Biochemistry Dean, College of Engineering Communicable Disease Center Communica 1sease . . . . . - ice ahfornla Institute of Technology Un1ver51ty of California, Berkeley Public Health Serv1ce 1311th Hear? 3? . pasadena U.S. Department of Health, Education, U.S. Department of Health, Education, Louis Roddis and Welfare, Atlanta, Georgia and WEHMB, Atlanta: Georgla Norman Hackerman Presiden't 3? Vice Chancellor for Academic AHairs Electric Company University of Texas, Austin Johnstown Aarie J. Haagen-Smit, Chairman Raymond J. Jessen I Leonhard Katz James E. Hill, Star]?r Professor of Biochemistry PrOfessor of Business Statistics President Bureau of Mines California Institute of Technology Graduate School of Business 5 Dynamics: 1510- U-S- Department Of the Interior Pasadena AdminiStration 2d Avenue, Northwest Industrial Park Washington University of California, Los Angeles Burlington, Massachusetts Louis H. Roddis, Vice Chairman President James L. Whittenberger Electric Company Professor of Public Health JOhnStown Harvard Of Public Health - John C. Geyer, Chairman Leonhard Katz Chairman President Nyle C, Brady W. J. Youden . . Director of Science and Education 4-821 Upton Street NW. Department Of samtary Engmeenng A530 . and Water Resources 2d Avenue, Northwest Industrial Park U.S. Department of Agriculture Washington Th . . . . Johns Hopkins Universuy Burlington, Massachusetts (until August 31, 1965) I . Director of the Cornell John L. Buckley, Staff I a t1more University Experiment Station A551Stant 3. Director of Research Of?ce Of SCienC? and New York State College of Agriculture WaShington Cornell University, Ithaca Martin Alexander, Chairman Deric O?Bryan, Sm}? Associate Professor of Soil Science Geological Survey . New York State College of Agriculture U.S. Department of the Interior Sal-3f, Cornell University, Ithaca Washington Roger Revelle, Chairman Charles D. Keeling Director, Center for Population Studies Scripps Institution of Oceanography ??a?rg??feyer Harvard La 0113? cahforma Department of Sanitary Engineering and . Water Resources . Sma orinsk . . . . g2i$3rirfog?igy {Veathegr Burezu The Johns Hopkins Baltimore Columbia University New York Environmental Sciences Services Administration Harmon Craig U.S. Department of Commerce Professor of Geochemistry Suitland, Maryland Martin Alexander, Chairman Deric O?Bryan, Staff of Earth Sciences Associate Professor of Soil Science Geological Survey University of ClailifornmJ La Jolla New York State College of Agriculture U.S. Department of the Interior Cornell University, Ithaca Washington SOLID WASTES Nyle 0. Brady Director of Science and Education JOhn Ch Galhoun: Jr -a Chairman PatriCk Conley U.S. Department of Agriculture Science Adviser to the Secretary Senior Fellow . (until August 31 1955) U.S. Department of the Interior Menon Immune: Director of the Coriiell University (until February 5, 1965) Vice President for Programs Texas A 8: University System College Station Experiment Station . Director of Research, New York State College of Agriculture Cornell University, Ithaca XII RESTORING THE QUALITY OF OUR ENVIRONMENT AQUATIC BLOOMS Martin Alexander, Chairman Associate Professor of Soil Science New York State College of Agriculture Cornell University, Ithaca John B. Moyle Department of Conservation St. Paul, Minnesota Ruth Patrick Academy of Natural Sciences Philadelphia, Leon Weinberger Division of Water Supply and Pollution Control Public Health Service US. Department of Health, Education, and Welfare, Washington Deric O?Bryan, Sta?r Geological Survey U.S. Department of the Interior Washington EFFECTS OF POLLUTANTS ON LIVING ORGANISMS OTHER THAN MAN David Pimentel, Chairman Head, Department of Entomology and Limnology New York State College of Agriculture Cornell University, Ithaca Don W. Hayne Professor of Experimental Statistics Institute of Statistics North Carolina State University Raleigh Louis A. Krumhoiz Professor of Biology University of Loui5ville John T. Middleton Director, Air Pollution Research Center University of California Riverside Lionel A. Walford Director, Sandy Hook Marine Laboratory Bureau of Sport Fisheries and Wildlife US. Department of the Interior Highlands, New Jersey John L. Buckley, Sta? Technical Assistant Of?ce of Science and Technology Washington IMPROVED PEST CONTROL PRACTICES David Pimentel, Chairman Head, Department of Entomology and Limnology New York State College of Agriculture Cornell University, Ithaca Donald A. Chant Chairman, Department of Biological Control University of California, Riverside Arthur Kelman Professor of Plant Pathology and Forestry North Carolina State University, Raleigh Present Address? Chairman, Department of Plant Pathology University of Wisconsin, Madison Robert L. Metcalf Vice Chancellor University of California, Riverside L. D. Newsom Head, Department of Entomology Louisiana State University, Baton Rouge Carroll N. Smith, ta]? Entomology Research Division Agricultural Research Service US. Department of Agriculture Gainesville, Florida Introduction Environmental pollution is the unfavorable alteration of our surroundings, wholly or largely as a by-product of man?s actions, through direct or indirect effects of changes in energy patterns, radiation levels, chemical and physical constitution and abundances of organisms. These changes may a?ect man directly, or through his supplies of water and of agricultural and other biological products, his physical objects or possessions, or his opportunities for recreation and appreciation of nature. The production of pollutants and an increasing need for pollution management are an inevitable concomitant of a technological society with a high standard of living. Pollution problems will increase in importance as our technology and standard of living continue to grow. Our ancestors settled in a fair and unspoiled land, easily capable of absorbing the wastes of its animal and human populations. Nourished by the resources of this continent, the human inhabitants have mul- tiplied greatly and have grouped themselves to form gigantic urban concentrations, in and around which are vast and productive industrial and agricultural establishments, disposed with little regard for state or municipal boundaries. Huge quantities of diverse and novel materials are dispersed, from city and farm alike, into our air, into our waters and onto our lands. These pollutants are either unwanted by-products of our activities or spent substances which have served intended purposes. By remaining in the environment they impair our economy and the quality of our life. They can be carried long distances by air or water or on articles of commerce, threatening the health, longevity, livelihood, recreation, cleanliness and happiness of citizens who have no direct stake in their production, but cannot escape their in?uence. Pollutants have altered on a global scale the carbon dioxide content of the air and the lead concentrations in ocean waters and human populations. Pollutants have reduced the productivity of some of our ?nest agricultural soils, and have impaired the quality and the safety of cr0ps raised on others. Pollutants have produced massive mortalities of ?shes in rivers, lakes and estuaries and have damaged or destroyed 1 2 RESTORING THE QUALITY OF OUR ENVIRONMENT commercial shell?sh and shrimp ?sheries. Pollutants have reduced valuable populations of pollinating and predatory insects, and have appeared in alarming amounts in migratory birds. Pollutants threaten the estuarine breeding grounds of valuable ocean ?sh; even Antarctic penguins and Arctic snowy owls carry pesticides in their bodies. The land, water, air and living things of the United States are a heritage of the whole nation. They need to be protected for the bene?t of all Americans, both now and in the future. The continued strength and welfare of our nation depend on the quantity and quality of our resources and on the quality of the environment in which our people live. The pervasive nature of pollution, its disregard of political boundaries including state lines, the national character of the technical, economic and political problems involved, and the recognized Federal responsibili- ties for administering vast public lands which can be changed by pollu- tion, for carrying out large enterprises which can produce pollutants, for preserving and improving the nation?s natural resources, all make it mandatory that the Federal Government assume leadership and exert its in?uence in pollution abatement on a national scale. We attempt here to describe the problem, to distinguish between what is known and what is not, and to recommend steps necessary to assure the lessening of pollution already about us and to prevent unacceptable environmental deterioration in the future RESTORING THE QUALITY OF OUR ENVIRONMENT an adequate number to start with. They should be selected by use nodern probability methods. waters of a single drainage area may vary from small trickles to lakes. In sampling these waters, however, we can take advantage the way in which the waters ?ow from smaller streams into larger rs, and from larger ones into rivers and lakes. [?he lands of a drainage area may vary even more widely: highly cul- l.th farm lands may grade through rangelands to rocky mountains and erts. All are part of the general environment; the pollution of all st be considered in the overall result. We can take advantage of what know about the likelihood of pollution of different kinds of land in nning the details of the sampling, but we must give all lands their )ropriate chance to contribute to the ?nal result. APPENDIX Y4 Atmospheric Carbon Dioxide ROGER REVELLE, Chairman C. D. KEELING J. SMAGORINSKY WALLACE BROECKER HARMON CRAIG Contents Section I. Carbon Dioxide From Fossil Fuels?The Invisible Pol- lutant . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . The Recent Increase in Atmospheric Carbon Dioxide . . . . . . . . Partition of Carbon Dioxide Among the Atmosphere, the Ocean, and the Biosphere . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Probable Future Content of Carbon Dioxide in the Atmos- phere . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Possible Effects of Increased Atmospheric Carbon Dioxide on Climate . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Other Possible Effects of an Increase in Atmospheric Carbon Dioxide . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Melting of the Antarctic Ice Cap . . . . . . . . . . . . . . . . . . . . . Rise of Sea Level . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Warming of Sea Water . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Increased Acidity of Fresh Waters . . . . . . . . . . . . . . . . . . . . Increase Other Possible Sources of Carbon Dioxide . . . . . . . . . . . . . . . . . Oceanic Warming . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Burning of Limestone . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Decrease in the Carbon Content of Soils . . . . . . . . . . . . . . . Change in the Amount of Organic Matter in the Ocean. . Changes in the Carbon Dioxide Content of Deep Ocean Water . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Changes in the Volume of Sea water . . . . . . . . . . . . . . . . . . Carbon Dioxide From Volcanoes . . . . . . . . . . . . . . . . . . . . . Changes Due to Solution and Precipitation of Carbonates. Conclusions and Findings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Section II. Detailed Computations . . . . . . . . . . . . . . . . . . . . . . . . . . . References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 111 Page 112 112 114 117 119 121 123 123 123 123 124 124 124 124 125 125 125 125 125 126 126 126 128 131 Section I. CARBON DIOXIDE FROM FOSSIL INVISIBLE POLLUTANT INTRODUCTION Only about one two-thousandth of the atmOSphere and one ten- thousandth of the ocean are carbon dioxide. Yet to living creatures, these smali fractions are of vital importance. Carbon is the basic build? ing block of organic compounds, and land plants obtain all of their carbon from atmospheric carbon dioxide. Marine plants obtain carbon from the dissolved carbon dioxide in sea water, which depends for its concentra- tion on an equilibrium with the carbon dioxide of the atmOSphere. Marine and terrestrial animals, including man, procure, either directly or indirectly, the substance of their bodies and the energy for living from the carbon compounds made by plants. All fuels used by man consist of carbon compounds produced by ancient or modern plants. The energy they contain was originally solar energy, transmuted through the biochemical process called The carbon in every barrel of oil and every lump of coal, as well as in every block of limestone, was once present in the atmosphere as carbon dioxide. Over the past several billion years, very large quantities of carbon dioxide have entered the atmOSphere from volcanoes. The total amount was at Ieast forty thousand times the quantity of carbon dioxide now present in the air. Most of it became combined with calcium or mag- nesium, freed by the weathering of silicate rocks, and was precipitated on the sea ?oor as limestone or dolomite. About one-fourth of the total quantity, at least ten thousand times the present atmospheric carbon dioxide, was reduced by plants to organic carbon compounds and became buried as organic matter in the sediments. A small fraction of this -- organic matter was transformed into the concentrated deposits we call. coal, petroleum, oil shales, tar sands, or natural gas. These are the fossil fuels that power the world?wide industrial civilization of our time. Throughout most of the half?million years of man?s existence on earth, I- his fuels consisted of wood and other remains of plants which had. grown only a few years before they were burned. The effect of this the content of atmospheric carbon dioxide was negligible, only speeded up the natural decay processes that continually re.? cycle carbon from the biosphere to the atmosphere. During the last centuries, however, man has begun to burn the fossil fuels that 112 APPENDIX Y4 113 locked in the sedimentary rocks over ?ve hundred million years, and this combustion is measurably increasing the atmospheric carbon dioxide. In the geologic past, the quantity of carbon dioxide in the atmosphere was determined by the equilibrium between rates of weathering and and the rate of injection of volcanic carbon dioxide. On an earthwide average, both weathering and must speed up when the carbon dioxide content of the air is increased, and slow down when it is diminished; consequently, over geologic time the carbon dioxide in the air must have risen when volcanic activity was high, and must have gone down when volcanoes were quiescent. On a human scale, the times involved are very long. The known amounts of lime- stone and organic carbon in the sediments indicate that the atmospheric carbon dioxide has been changed forty thousand times during the past four billion years, consequently the residence time of carbon in the atmos? phere, relative to sedimentary rocks, must be of the order of a hundred thousand years. The present rate of production of carbon dioxide from fossil fuel com? bustion is about a hundred times the average rateof release of calcium and magnesium from the weathering of silicate rocks. As long as this ratio holds, precipitation of metallic carbonates will be unable to main- tain an unchanging content of carbon dioxide in the atmosphere. Within a few short centuries, we are returning to the air a signi?cant part of the carbon that was slowly extracted by plants and buried in the sediments during half a billion years. Not all of this added carbon dioxide will remain in the air. Part of it will become dissolved in the ocean, and part will be taken up by the biosphere, chie?y in trees and other terrestrial plants, and in the dead plant litter called humus. The part that remains in the atmosPhere may have a signi?cant effect on climate: carbon dioxide is nearly transparent to visible light, but it is a. strong absorber and back radiator of infrared radiation, particularly in the wave from 12 to 18 microns; con- sequently, an increase of atmospheric carbon dioxide could act, much like the glass in a greenhouse, to raise the temperature of the lower air. [Water vapor also absorb-s infrared radiation, both in the range of the C02 band centered at 15 microns, and at wave near 6.3 microns. With the average concentration of water vapor in the lower air at mid latitudes, the effect of carbon dioxide absorption is reduced to about half that which would exist in an absolutely dry atmosphere. (Moller, 1963.) Ozone, which is an important constituent of the upper air, also absorbs some infrared at wave around 9.6 microns, but its princi- pal effect on air temperature is due to its absorption of ultraviolet and Visible sunlight] The possibility of climatic change resulting from changes in the quan? tity of atmospheric carbon dioxide was proposed independently by the 11-4: RESTORING THE QUALITY OF OUR ENVIRONMENT American geologist, T. C. Chamberlain (1899) and the Swedish chemist, S. Arrhenius (1903), at the beginning of this century. Since their time, many scientists have dealt with one or another aspect of this question, but until very recently there was little quantitative information about what has actually happened. Even today, we cannot make a useful prediction concerning the magnitude or nature of the possible climatic effects. But we are able to say a good deal more than formerly about I the change in the quantity of atmospheric carbon dioxide, and about I the partition of carbon dioxide from fossil fuel combustion among the atmosphere, the ocean, and the biosphere. THE RECENT INCREASE IN ATMOSPHERIC CARBON DIOXIDE During the ?ve years from 1958 through 1962, 5.3 1016 grams of carbon dioxide were produced by the combustion of coal, lignite, petro- - leum and other liquid hydrocarbons, and natural gas (see Tables 1 and 2). TABLE 1.?Carbon Dioxide Produced by Fossil Fuel Combustion, 1950?62 [1016 grams] As of Liquid Natural Atmos- Year Goal 1 Lignite 2 Hydro- Gas 4 Total pheric carbons 3 002 in 1950 I 1950 . . . . . . . . . . . . 1951 . . . . . . . . . . .. .1952 . . . . . . . . . . .. .38 .09 .21 .05 .73 .31 1953 .. .33 .09 .22 .05 .74 .32 1954 . . . . . . . . . . .. . 1955 . . . . . . . . . . .. .1956 . . . . . . . . . . .. .1957 . . . . . . . . . . .. .1958 . . . . . . . . . . .. .1959 . . . . . . . . . . .. .43 .14 .32 .09 1.03 .44 - 1960 . . . . . . . . . . .. .50 .14 .34 .10 1.08 .46- I . 1961 . . . . . . . . . . .. .48 .15 .36 .10 1.09 ,46 19_62...50 .15 .39 .11 1.15 .49 .1 Total . . . . . .. 5.Assumed. carbon content, coal=75 percent. 3 Assumed carbon content, lignite=45 percent. 3 Assumed carbon content, liquid hydrocarbons=86 percent. 4 Assumed carbon content, natural gas=70 percent. (Corresponding to a mixtur?k'bY volume of '80 percent CH4, 15 percent 021-15 and 5 percent N2.) Source: Computed from Table 2. .5 . APPENDIX Y4 115 TABLE 2?Waer Production of Fossil Fuelsm1950?62 [Millions of Metric Tons] Liquid Natural Year Coal Lignite Hydro- Gas 2 Total carbons I 1950 . . . . . . . . . . . . . . . . . 1, 340 530 540 155 2, 565 1951 . . . . . . . . . . . . . . . . . . 1, 375 550 620 180 2, 725 1952 . . . . . . . . . . . . . . . . . . 1, 375 550 655 200 2, 780 1953 . . . . . . . . . . . . . . . . . . 1, 380 555 690 210 2, 835 1954 . . . . . . . . . . . . . . . . . . 1, 375 550 725 220 2, 870 1955 . . . . . . . . . . . . . . . . . . 1, 500 630 790 240 3, 160 1956 . . . . . . . . . . . . . . . . . . 1, 595 665 860 260 3, 380 1957 . . . . . . . .580 1958 . . . . . . . . . . . . . . . . .. 1,665 325 930 305 3,725 1959 . . . . . . . . . . . . . . . . . . 1, 730 845 995 345 3, 915 1960 . . . . . . . . . . . . . . . . . . 135 1961 . . . . . . . . . . . . . . . . . . . 205 1962 . . . . . . . . . . . . . . . . . . 385 Total . . . . . . . . . . . . . . 20Includes Petroleum and Natural Gasoline. 2 Assumed density of gm cm?3 (1000m3=0.8 ton). Source: 'World Energy Supplies. Statistical Papers, Series J, United Nations, New York. This is 2.25 percent of the 2.35 1018 grams of carbon dioxide pres- ent in the atmosphere in 1950 (assuming an atmospheric carbon dioxide concentration of 300 by volumeh?445 by weightwand a mass of 5.2 1021 grams for the entire atmosphere.) On the average during 1958?1962, the 002 produced each year by fossil fuel combustion was 0.45 percent of the quantity in the atmosphere. Beginning in 1958 and extending through 1963, two nearly continuous series of measurements of atmospheric content were made.- One of these series was taken at the US. Weather Bureau station near .-_the top of Mauna Loa Mountain in Hawaii (Pales and Keeling, 1965 other at the United States scienti?c station at the South Pole (Brown and Keeling, 1965). The measurements were carried out on in- frared gas spectrometer, with a relative accuracy for a Single measure- ment of about i0.1 ppm. The observing stations arelocatednear-the centers of vast atmospheric mixing areas, far from uncontrollablesources . of contaminants. Because of thesenearly ideal locations,- the high precision of the instruments, and the extreme care: the samples were taken, these 'measurementsmake' the secular trend of atmospheric 002 with an accuracy I I .- APPENDIX Y4 117 ?116 RESTORING THE QUALITY OF OUR ENVIRONMENT TABLE 4,?World Production of Fossil Fuels, 1860?1959 [Millions of Metric Tons] '1 5 orders of magnitude than ever before. Some ?fteen thousand measure? 1: were carried out during the ?ve-year period. InfTh: data show, clearly and conclusively, that from 1958 through 1963 increased 1.36 ercent. Liquid Nam al the carbon diox1de content of the atmospher 1 I th a Decade Coal Lignite Hydro? Gas 2 Total The increase from year to year was quite regu ar, ose to aver carbon? annual value of 0.23 percent. By comparing the measured increase with the known quantity of carbon dioxide produced by foss? fuel com- 1860_69 750 bustion, given in Table 4, we see that almost exactly half of the fossil 187049 755 fuel 002 apparently remained in the atmosphere. if 1:33-33(5) 2593: 1:3 :3 461, 333 aunt Tables 3 and 4?show that between 1860 and 19401the am b2 2: 1900?725 produced by foss? combustion, chiefly coal, was .9 percenttan 191049 11,240 1,270 590 155 13,255 1950, 10.3 percent, of the estimated atmospheric content in 1950. 1920_29 1959 the total 002 production was equal to 13.8 percent of the r? 1930?11,500 2,135 2, 335 485 16,455 3 . atmospheric C02. Unfortunately, the accuracy of measurements of Egg-:605 970 21, 140 atmospheric 002 before 1958 is too low to allow estimates of the secular - - - - - - - - - - - - - - - 7, 710 2, 400 31, 535 variation, and it is therefore impossible to compute directly whether the Total . . 425 122, 415 fraction of fossil-fuel COP. remaining in the atmosphere throughout-the . lowl or ra idl chan . .1 P381: hundred years has been conStant? 0r 1 Includes petroleum and natural gasoline. - 2As dd f8 10"4 ?3 100 3::08 . TABLE 3.?Carbon Dioxide Produced by Fossil Fuel Combustzon, 1860?1959 sume ?may 0 gm Cm 0 ton) Sources: From 1860 to 1949, United Nations, Department of Economic and Social [1016 grams] Affairs: ?World Energy RCqUireantS?. Proceedings of the International Conference 2 i i 3? on. the Peaceful Uses of Atomic Energy, Vol. 1, pp. 3?33, 1956. For 1950?59, As of United Nations, World Energy Supplies. Statistical papers, Series I, United Nations, Liquid Natural AthS- New York. Decade Goal 1 Lignite 2 Hydro?3 Gas 4 Total carbons 1950 There are measurements of a somewhat different kind, which can give us useful information hmvever. These are determinations of the so- 1860?0.called ?Suess Effect.? 0..73 .31 1880?1.1.13 .48 PARTITION OF CARBON DIOXIDE AMONG THE ATMOS- 1890?'69 PHERE THE OCEAN AND THE BIOSPHERE 1900-2.33 .15 .10 .02 2.60 1.11 1910??1920.29 I i 3, 26 .31 .48 .07 4.12 1. 75 i ecause oss1 no 5 ave een uric . or ions 0 years, ey 1930-3.16 .35 .74 .12 4.37 1.86 contain no Carbon 14:. (This radioactive isotope is produced in the 1940?.49 1.atmosphere by cosmic ray bombardment of nitrogen, and' it has a half? 1950459 . . . . . . . .. 4.life of only about six thousand years.) Consequently, the addition to Tomi 23' 41 2. 75 5'the atmosphere of C02 from fossil fuel combustion, and its subsequent partition among the atmosphere, the ocean, and the blosphere Will cause the ratio between radioactive and nonradioactive carbon to decrease. 1 Assumed carbon content, coa1?75 Percent This manifests itself as a measurable reduction in the amount of radio- ZQEZZS =86 Percent ative carbon, for example, in tree rings grown in recent years compared 4 Assumed carbon content: natural gas=70 percent. (Corresponding toamixture by With rings that grew during the 19th Century. This reduction, due to volume of 80 percent 15 percent (3,116 and 5 percent N2). foss? fuel combustion, is called the ?Suess Effect,? after Professor Hans Suess, who ?rst observed it (see Revelle and Suess, 1956). 1 Source: Computed from Table 4. 118 RESTORING THE QUALITY or OUR ENVIRONMENT The measurement of the ?Suess Effect? is beset with many dif?culties, the chief among them being that the Carbon 14 content of the atmos- pherewmore precisely the ratio of to Gui-Clamvaries by or 2 percent from century to century apparently depending on the long-term variations in sunspot intensity. Tree ring measurements show that this ratio went up during the 15th and 17th Centuries, and down during the 16th and 18th, in each case by about 2 percent (Suess, 1956). Prior to the atomic weapons tests of the mid?Fifties, the ratio was lower by be? tween 1 and 2 percent than in the middle of the 19th Century. This change during the past hundred years was apparently largely due to the ?Suess Effect.? Taking the ?Suess Effect? as between 1 and 2 percent over the period from 1860 to 1950, during which time the total carbon dioxide produced from fossil fuels was 10% of the atmospheric cog, and assuming that presently occurring changes in the magnitude of the ?Suess Effect? are in the same proportion to (102 from fossil fuel combustion as in the past, we can compute both the relative sizes of the oceanic and biosphere reservoirs that are taking up part of the added 002, and the partition of C02 between these reservoirs. The amount taken up in the biosphere will be different if there are two or more sources of additional carbon dioxide, than if fossil fuels are the only source, but the amount absorbed by the ocean will not vary. Implied in the calculation is the further assumption that any 002 from other sources will have about the same ratio of C14 to total carbon as the atmosphere. Details are given in Section II. The calculation shows that if the oceanic layer mixing with the atmos~ phere is several hundred meters thick, the amount of exchangable carbon in the biosphere is less than or about equal to that in the atmosphere. These are both ?reasonable? values. On the other hand, if another signi?cant source of C02 is assumed for the last few decades, the amount of 002 added to the biosphere becomes so large that it should have been observed. In fact, no increase in the biosphere has been noted. Per- haps the most striking result is that the ocean takes up a relatively small fraction of the total added 002, probably about 15%. In the past, the usual scienti?c belief has been that by far the larger part of any added C02 would be absorbed in the ocean. This is undoubtedly true if we consider a suf?ciently long time period, of the order of thousands or even, perhaps, hundreds of years, because the ocean as a whole contains nearly sixty times as much carbon dioxide as the atmosphere. But over shorter times, only the uppermost layers of the ocean take part in ex? changes with the air. Moreover, most of the oceanic carbon dioxide is present as carbonate and bicarbonate, balanced against metallic cations, "294' APPENDIX Y4 1 and a marked increase in oceanic 002 therefore requires an increase in cation concentration, Can be brought about only by rock weather- ing or solution of calc1urn~nch sediments. These are slow processes. PROBABLE FUTURE CONTENT OF CARBON DIOXIDE IN THE ATMOSPHERE We can conclude with fair assurance that at the present time, fossil fuels are the only source of C02 being added to the ocean-atmosphere- biosphere system. If this held true throughout the last hundred years, the quantity of C02 in the air at the beginning of the present decade was about 7% higher than in the middle of the last century (see Table 3). Throughout these hundred years, the rate of fossil fuel combustion, and thus of C02 production, continually increased, on the average about 3.2 percent per year. The amount produced in 1962 was almost 25 times the annual production in the mid?1860?s. The rate of increase may be accelerating. During the eight years from '1954 to 1962, the average rate of increase was 5 We can ask several questions about the future C02 content of the atmosphere. Two of these questions are: (1) What will the total quantity of injected into the at- mosphere but only partly retained there) be at different future times? . (2) What would be the total amount of injected into the air if all recoverable reserves of fossil fuels were consumed? At present rates of expansion in fossil fuel consumption this condition could be approached within the next 150 years. . The second question is relatively easy to answer, provided we consider only the estimated recoverable reserves of fossil fuels. The data are shown in Table 5. We may conclude that the total C02 addition from fossil fuel combustion will be a little over 3 times the atmospheric content, and that, if present partitions between reservoirs are maintained, the C02 in the atmosphere could increase by nearly 170 percent. The answer to the ?rst question depends upon the rate of increase of fossil fuel combustion. Table 6 shows that if this combustion remains constant at the 1959 level, the total C02 injected into the atmosphere by the year 2000 will be about 28 percent of the atmospheric content in 1950. If the average rate of increase of combustion continues at 3.2 percent per year, the quantity injected into the atmosphere by the year 2000 will be about 4:2 percent; if the 5% rate Of increase during the last 8 years persists, the quantity injected will be close to 60 percent. Assuming further that the proportion remaining in the atmosphere continues to be half the total quantity injected, the increase in amospheric C02 in the year 2000 could be somewhere between 14: percent and 30 percent. I 120 RESTORING THE QUALITY or OUR ENVIRONMENT Based on projected world energy requirements, the United Nations Department of Economic and Social Affairs (1956) has estimated an amount of fossil fuel combustion by the year 2000 that with our assumed partitions would give about a 25 percent increase in atmospheric 002, compared to the amOunt present during the 19th Century. For con- venience, we shall adopt this ?gure in the following estimate of the effects on atmospheric radiation and temperature. TABLE 5.?Estimated Remaining Reserves of Fossil Fuels Carbon As of 109 Metric Dioxide Atmospheric Tons Equivalent, 002 in 1950 1018 Coal and Lignite 252 Petroleum and Natural Gas Liquids Natural Gas Tar Sands Oil Shales Total . . . . . . . . . . . . . . . . . . . . . . . . . . . 2, 971 7. 85 336 1 Assumed to be 20 percent lignite containing 45 percent carbon, and 80 percent bituminous coal containing '75 percent carbon. 2 Assumed carbon content of petroleum, natural gas liquids, and hydrocarbons re? coverable from tar sands and oil shales=86 percent. 3 Assumed composition of natural gas by volume: percent, C2H6215 percent, percent. Source: Computed from data given by M. King Hubbei?t, ?Energy Resources, A Report to the Committee on Natural Resources of the National Academy of Sciences?- National Research Council,? NAS Publication 1000?13, 1962, pp. 1?141. TABLE 6.??Estimates of Carbon Dioxide From Fossil Fuel Combustion in Future Decades, Assuming Di?erent Rates of Increase of Fuel Use Year As percent of Atmospheric CO, in 1950 Growth rate, percent/year . . . . . . . . . . . . . . . 0 3. 2 5. 1959 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 13. 80 13. 80 13. 80 1969 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 17. 30 18. 00 18. 47 1979 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20. 79 23. 79 26. 15 1989 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24. 28 31. 94 37. 90 1999 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27. 77 41. 96 58. 75 2009 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31. 26 57. 04 93. 14 APPENDIX Y4 121 POSSIBLE EFFECTS OF INCREASED ATMOSPHERIC CARBON DIOXIDE ON CLIMATE One of the most recent discussions of these effects is given by Mo'ller (1963). He considers the radiation balance at the earth?s surface with an average initial temperature of a relative humidity of 75 percent, and 50% cloudiness. We may compute from his data that with a 25 percent increase in atmospheric C02, the average temperature near the earth?s surface could increase between and to depending on the behavior of the atmospheric water vapor content. The small increase would correspond to a constant absolute humidity, that is, a constant weight of water in the atmosphere. The larger increase would correspond to a constant relative humidity, that is, as the temperature rose, the water vapor content would also rise to maintain a constant percentage of the saturation value. A doubling of C02 in the air, which would happen if a. little more than half the reserves of fossil fuels were consumed, would have about three times the effect of a twenty??ve percent increase. As Moller himself emphasized, he was unable to take into account the vertical transfer of latent heat by evaporation at the surface and conden- sation aloft, or of sensible heat by convection and advection. For this reason he was unable to consider the interactions between di?erent at- mospheric layers in a vertical column. - In consequence, Moller?s com? putations probably over-estimate the effects on atmospheric temperature of a C02 increase. A more comprehensive model is being developed by the U.S. Weather Bureau. This includes processes of convection and of latent heat transfer through the evaporation and condensation of water vapor. Meaningful computations should be possible with this model in the very near future. But climatic changes depend on changes in the general circulation in the atmosphere, and these will be related to the spatial distribution and time variation of carbon dioxide and water vapor. The ratio of C02 to water vapor is higher in the polar regions than in low latitudes, higher in winter than in summer, and much higher in the stratosphere than near the ground. For example, the volume of carbon dioxide in the atmosphere at high latitudes is about half the volume of water vapor, while near the equator it is less than a tenth of the water vapor volume. As a result, the radiation balance of the earth will be a?ected differently at different seasons, latitudes, and heights by changes in the atmospheric 002 content. Without a comprehensive model in? corporating both the ?uid dynamics and the radiation transfer processes of the atmosphere it is not possible to predict how these effects will per? turb the general circulation. Such a model may be available within the next two years. 122 RESTORING THE QUALITY or OUR ENVIRONMENT Models of atmospheric thermal equilibrium in which vertical convec- tion is allowed to maintain the observed vertical temperature gradient have recently been constructed by S. Manabe of the US Weather Bureau (Manabe and Strickler, 1964; Manabe, 1965). These show that the effect of infra red absorption from the present atmospheric carbon di- oxide at mid latitudes is to maintain a ground temperature about higher than would prevail if no were present. An increase in the C02 content without a change in absolute humidity would, ac- cording to these models, produce a somewhat smaller surface tempera- ture rise than that estimated by Moller. But a considerable change would occur in the stratosphere, where the 002 concentration by volume is perhaps 50 times that of water vapor. A 25% rise in carbon dioxide would cause stratospheric temperatures to fall by perhaps at an altitude of 30 kilometers (about 100,000 feet) and by at 40 kilometers (about 130,000 feet). One might suppose that the increase in atmospheric 002 over the past 100 years should have already brought about signi?cant climatic changes, and indeed some scientists have suggested this is so. The English meteorologist, G. S. Callendar (1938, 1940, 1949), writing in the late 1930?s and the 1940?s on the basis of the crude data then avail?- able, believed that the increase in atmospheric 002 from 1850 to 1940 was at least 10%. He thought this increase could account quantitatively for the observed warming of northern Europe and northern North America that began in the 1880?s. From Table 2 and our estimate of the 002 partition between the atmospheric, the ocean, and the biosphere, we see that the actual C02 increase in the atmosphere prior to 1940 was only at least from fossil fuel combustion. This was probably in- sufficient to produce the observed temperature changes. [But it should be noted that up to 2.5% of the atmospheric carbon dioxide (after par? tition with the ocean and the biosphere) could also have been added by the oxidation of soil humus in newly cultivated lands] As Mitchell (1961, 1963) has shown, atmospheric warming between 1885 and 1940 was a world-wide phenomenon. Area-weighted averages for surface temperature over the entire earth show a rise in mean annual air temperature of about World mean winter tempera- tures rose by Warming occurred in both hemispheres and at all latitudes, but the largest annual rise or was ob- served between 40? and 70? latitudes. In these latitudes, the average winter temperatures rose by . The pronounced warming of the surface air did not continue much beyond 1940. Between 1940 and 1960 additional warming occurred in northern Europe and North America, but for the world as a Whole and also for the northern hemisphere, there was a slight lowering of about in mean annual air temperature (Mitchell, 1963). Yet dur- APPENDIX 4 1 ing this period more than 40% of the total 002 increase from fossil fuel combustion occurred. We must conclude that climatic ?noise? from other processes has at least partially masked any effects on climate due to past increases in atmospheric 002 content. OTHER POSSIBLE EFFECTS OF AN INCREASE IN ATMOSPHERIC CARBON DIOXIDE Melting of the Antarctic ice cap?It has sometimes been suggested that atmospheric warming due to an increase in the content of the atmosphere may result in a catastrophically rapid melting of the Antarc- tic ice cap, with an accompanying rise in sea level. From our knowl- edge of events at the end of the Wisconsin period, 10 to 11 thousand years ago, we know that melting of continental ice caps can occur very rapidly on a geologic time scale. But such melting must occur relatively slowly on a human scale. The Antarctic ice cap covers 14 million square kilometers and is about 3 kilometers thick. It contains roughly 4 1016 tons of ice, hence 4 1024 gram calories of heat energy would be required to melt it. At the present time, the poleward heat ?ow across 70? latitude is 1022 gram calories per year, and this heat is being radiated to space over Antarctica without much measurable effect on the ice cap. Suppose that the pole- ward heat ?ux were increased by 10% through an intensi?cation of the meridional atmospheric circulation, and that all of this increase in the ?ow of energy were utilized to melt the ice. Some 4,000 years would be required. We can arrive at a smaller melting time by supposing a change in the earth-wide radiation balance, part of which would be used to melt the ice. A 2% change could occur by the year 2000, when the atmospheric C02 content will have increased perhaps by 25%. Since the average radiation at the earth?s surface is about 2 10?5 gram calories per square centimeter per year, a 2% change would amount to 2 10?2 calories per year. If half this energy were concentrated in Antarctica and used to melt the ice, the process would take 400 years. Rise of sea lend?The melting of the Antarctic ice cap would raise sea level by 400 feet. If 1,000 years were required to melt the ice cap, the sea level Would rise about 4 feet every 10 years, 40 feet per century. This is a hundred times greater than present worldwide rates of sea level change. Warming of sea water.#If the average air temperature rises, the temperature of the surface ocean waters in temperate and tropical re- gions could be expected to rise by an equal amount. (Water tempera- tures in the polar regions are roughly stabilized by the melting and freezing of ice.) An oceanic warming of 1? to (about oc-_ 124 RESTORING THE QUALITY or OUR ENVIRONMENT curred in the North Atlantic from 1880 to 194:0. It had a pronounced effect on the distribution of some ?sheries, notably the cod ?shery, which has greatly increased around Greenland and other far northern waters during the last few decades. The amelioration of oceanic climate also resulted in a marked retreat of sea ice around the edges of the Arctic Ocean. Increased acidity of fresh waters.?Over the range of concentrations found in most soil and ground waters, and in lakes and rivers, the hydro~ gen ion concentration varies nearly linearly with the concentration of free C02. Thus the expected 25% increase in atmospheric 002 concentra- tion by the end of this century should resnlt in a 25% increase in the hydrogen ion concentration of natural waters or about a 0.1 drOp in pH. This will have no signi?cant effect on most plants. Increase in areas where water and plant nutrients are abundant, and Where there there is su?icient sunlight, carbon dioxide may be the limiting factor in plant growth. The expected 25 increase by the year 2000 should signi?cantly raise the level of in such areas. Although very few data are available, it is commonly be- lieved that in regions of high plant productivity on land, such as the trop- ical rain forests, phosphates, nitrates and other plant nutrients limit pro? duction rather than atmospheric This is probably also true of the oceans. Biological processes are speeded up by a rise in temperature, and in re- gions where other conditions are favorable higher temperatures due to increased C02 might result in higher plant production. OTHER POSSIBLE SOURCES OF CARBON DIOXIDE We are fairly certain that fossil fuel combustion has been the only source of 002 coming into the atmosphere during the last few years, when accurate measurements of atmospheric carbon dioxide content have been available. Carbon dioxide may have been produced by other sources during earlier times but it is not now possible to make a quantita- tive estimate. However we can examine the order of magnitude of some of the possible inputs from other sources, on the basis of our knowledge of the processes that might be involved. Oceanic warming?The average temperature of the ocean cannot have increased by more than during the past century, since any greater warming would have caused a larger rise in sea level than the observed value of about 10 centimeters. A more probable upper limit is because most of the sea level rise can be?accounted for by glacial melting. An average rise would corre3pond to 05? in the top 4:00 meters. This would cause a nearly 3% rise in the 002 partial pressure. APPENDIX Y4 125 After equilibration with the atmosphere, the partial pressure in both the air and the uppermost ocean layer would be higher by about Burning of limestone.??Annual world production of carbon dioxide from the use of limestone for cement, ?uxing stone, and in other ways, is about 1% of the total from fossil fuel combustion, or 4- 10"5 of the atmospheric content per year. Decrease in the carbon content of the middle of the Ninetenth Century, the world?s cultivated farmland has been enlarged by about 50%. This is an increase of close to a billion acres or 1.6 million square miles, corresponding to 2.7% of the land area of the earth, and perhaps to 5% of forests and grass lands. Most soil humus is believed to be concentrated in forests and grassy areas. Assume that the total humus is equal to twice the amount of carbon in the atmosphere and that half the carbon in the humus of the newly cultivated lands has been oxi? dized to carbon dioxide. The total injected into the atmosphere from this source becomes less than 5 of the atmospheric C02. Change in the amount of organic matter in the ocean?About 7% of the marine carbon reservoir consists of organic material. Since a 1% change in the carbon dioxide content of the ocean changes the (302 pressure by 12.5%, a decrease by 1% in the marine organic carbon (which would increase the total oceanic carbon dioxide by .07 would raise the carbon dioxide pressure of the ocean and the atmosphere by about An increase in the temperature of water near the surface, during the past one hundred years, could have speeded up the rate of oxidation of organic matter relative to its rate of production by photo- Measurements of the content of organic matter in the ocean are neither accurate enough nor suf?ciently extended over time to allow a direct estimate of this possibility. A change of several percent could have occurred without detection. Changes in the carbon dioxide content of deep ocean avatar-The deep ocean waters contain about 10% more carbon dioxide than they would if they were at equilibrium with the present atmospheric content. This is a result of the sinking of dead organic remains from the surface waters and their subsequent oxidation in the depths. The combination of biological and gravitational processes can be thought of as a pump that maintains a relatively low carbon dioxide content in the surface waters and in the atmosphere. If the pump ceased to act, the atmos? pheric carbon dioxide would eventually be increased ?ve fold. Varia~ tions in the effectiveness of the pump could have occurred without detec- tion during the past 100 years, and could have caused notable changes in the atmospheric carbon dioxide content. - Changes in the volume of sea water.??During the Ice Age the volume of sea water varied by about Changes of this magnitude would change the carbon dioxide content of the atmOSphere by 10 to 126 RESTORING THE QUALITY OF OUR ENVIRONMENT But during the last several thousand years, variations in oceanic volume have been small. During the past hundred years, world average sea level has varied by less than 10 centimeters. This very small volume change would have no appreciable effect on the atmospheric carbOn dioxide. Carbon dioxide from volcanoes.??Over geologic time, volcanic gases have been the principal sources of new carbon dioxide injected into the atmosphere. On the average the in?ux of volcanic CO2 must have balanced the extraction from the atmosphere by rock weathering. The present rate of in?ux of volcanic 002 is close to a hundred fold less than that from fossil fuel combustion. No data exist on the worldwide level of volcanic activity over geologic time. It is conceivable that the level has ?uctuated by orders of magnitude, and that the ?uctuations persisted for millenia, or even for millions of years. Changes due to solution and precipitation of and magnesium carbonate precipitation on the sea ?oor lower the total 002 content of ocean water, but increase the carbon dioxide pressure and the free 002 content. Conversely, chemical weathering of lime- stone and dolomite on land lower the atmospheric G02 and the free 002 content of the sea, but increase the total oceanic 002. The rates of these processes are about one order of magnitude lower than the present rate ?of production of carbon dioxide by fossil fuel combustion. We conclude that the only sources of carbon dioxide comparable in magnitude to fossil fuel combustion during the last 100 years could have been a decrease in soil hu?mus due to the increase in the area of culti- vated lands, a decrease in the content of ?dissolved? organic matter in the ocean, or a lowering of the carbon dioxide content of deep ocean waters. Marked changes in the oceanic regime would have been neces sary for the latter two processes to have signi?cant effects. As we have shown, none of the three processes are likely to be signi?cant at the pres- ent time. Nor are any oceanographic data available which suggest that the required changes in the ocean occurred during the last hundred years. CONCLUSIONS AND FINDINGS Through his worldwide industrial civilization, Man is unwittingly corr- ducting a vast geophysical experiment. Within a few generations he is burning the fossil fuels that slowly accumulated in the earth over the past 500 million years. The (102 produced by this combustion is being injected into the atmosphere; about half of it remains there. The esti- mated recoverable reserves of fossil fuels are suf?cient to produce nearly a 200% increase in the carbon dioxide content of the atmosphere. By the year 2000 the increase in atmospheric 002 will be close to 25%. This may be su?icient to produce measurable and perhaps marked APPENDIX Y4: 127 changes in climate, and will almost certainly cause signi?cant changes in the temperature and other properties of the stratosphere. At present it is impossible to predict these effects quantitatively, but recent advances in mathematical modelling of the atmosphere, using large computers, may allow useful predictions within the next 2 or 3 years. Such predictions will need to be checked by careful measurements: a series of precise measurements of the 002 content in the atmosphere should continue to be made by the U.S. Weather Bureau and its col? laborators, at least for the next several decades; studies of the oceanic I and biOIOgical processes by which 002 is removed from and added to the atmosphere should be broadened and intensi?ed; temperatures at different heights in the stratosphere should be monitored on a worldwide basis. The climatic changes that may be produced by the increased 002 content could be deleterious from the point of view of human beings. The possibilities of deliberately bringing about countervailing climatic changes therefore need to be thoroughly explored. A change in the radiation balance in the opposite direction to that which might result from the increase of atmospheric 002 could be produced by raising the albedo, or re?ectivity, of the earth. Such a change in albedo could be brought about, for example by spreading very small re?ecting particles over large oceanic areas. The particles should be suf?ciently buoyant so that they will remain close to the sea surface and they should have a high re?ectivity, so that even a partial covering of the surface would be adequate to produce a marked change in the amount of re?ected sun- light. Rough estimates indicate that enough particles partially to cover a square mile could be produced for perhaps one hundred dollars. Thus a 1% change in re?ectivity might be brought about for about 500 million dollars a year, particularly if the re?ecting particles were spread in low latitudes, where the incoming radiation is concentrated. Considering - the extraordinary economic and human importance of climate, costs of this magnitude do not seem excessive. An early development of the needed technology might have other uses, for example in inhibiting the formation of hurricanes in tropical oceanic areas. According to Manabe and Strickler (1964) the absorption and re- radiation of infrared by high cirrus clouds (above ?ve miles) tends to heat the atmosphere near the earth?s surface. Under some circum- stances, injection of condensation or freezing nuclei will cause cirrus clouds to form at high altitudes. This potential method of bringing about climatic changes needs to be investigated as a possible tool for modifying atmospheric circulation in ways which might counteract the effects of increasing atmospheric carbon dioxide. 128 RESTORING THE QUALITY OF OUR ENVIRONMENT Section II. DETAILED COMPUTATIONS Calculation of the Relative Sizes of the Ocean and Biosphere Reservoirs and the Probability of Other Sources of Carbon Dioxide at the Present Time A portion of the carbon dioxide coming into the atmosphere will be transferred to the ocean, and another part will enter the biosphere. We can test the possibility of carbon dioxide sources other than fossil fuel combustion by examining the relative sizes of the required ocean and biosphere reservoirs. Let A 002 in atmosphere. Bxequivalent C02 in the part of the biosphere that exchanges with the atmosphere. in the oceanic reservoir that exchanges with the atmosphere. AA, AB, AM =changes in (302 content of these reservoirs. A01402 in the reservoir system, 02 . AA . . a?g=fractional change of atmospheric 002 content. fA=002 produced by fossil fuel combustion. bA =00; produced by other processes. Then, at equilibrium, (f+b)A AM where owing to the buiTer mechanism of sea water (Bolin and Eriksson, 1958). And assuming that 002 produced by other processes has approxi- mately the same (314 content as the atmospheric C102, and knowing that fossil fuel 002 contains no 014. APPENDIX Y4: 129 Solving for AB, M, and AM, we ?nd (gm?l?c) (2) (3) Where 6?2 We know from measurements of tree rings grown during the middle of the Nineteenth Century, compared with those grown during the last few years, that for the period 1850?1950 0.02252 0.01 (the ?Suess Effect?) During this same period, 20.1, hence s? 32 n? The series of atmospheric GO2 measurements at Manna Loa and Antarctica from 19584963 show that during these years Substituting in equations (1), (2) and (3) we ?nd, for different A AB values of and g: the values shown in Table 7 for g: and From this table we see that with a ?Suess Effect? of 2% (the most prob? able value), With fossil fuel combustion as the sole source of additional 002, and with ?effective? biosphere sizes of 2.5 to 0.5 times the atmos? pheric C02, the oceanic reservoir is 2.6% to 6.0% of the volume of the oceans, equivalent to a layer of water 100 to 240 meters thick just below the surface. The size of the oceanic reservoir varies inversely with the size of the biosphere. For a ?Suess Effect? of 1% (probably too low), and the same range of biosphere sizes, the assumed layer of complete mixing contains 11% to 14% of the ocean volume, and has an e?ective thickness of 440 to 560 meters. I30 RESTORING THE QUALITY OF OUR ENVIRONMENT TABLE Sizes of Oceania and Biosphere Reservoirs and Partition of Added 002 Among Reservoirs 5:0; s=0.2f; a=0.004 1.0 3.0 .38 .12 .038 .004 1.5 2.5 .40 .10 .027 .004 004 2.5 1.5 .44 .06 .018 .004 6:0; a=0.8.0 .18 .32 .018 .004 1 5 7.5 .20 .30 .013 .004 2 0 7.0 .22 .28 .011 .004 004 b=.5f; a=0.5f 0.5 3.5 .86 .14 .172 .004 1.0 3.0 .88 .12 .088 .004- 1.5 2.5 .90 .10 .060 .004 038 .004 A layer of water a few hundred meters thick would be acceptable to oceanographers as de?ning mixing over several decades. Hence, if the ?Suess Effect? is close to the size of the biosphere reservoir is prob- ably about equal to, or less than, that of the atmospheric reservoir. This coincides with other estimates that the effective size of the biosphere on land, including both living organisms and humus, ranges from V2 to one times the atmospheric carbon content. Possibly the organic content of the oceanic mixing layer should be included in the biosphere reservoir, but this is only a few tenths of the atmospheric C02. In terms of the amounts of carbon they contain, the biosphere reservoir is much smaller than the oceanic reservoir. However, over short times in the ocean, only the relatively small ?free? 00;; content (dissolved and hydrated carbon dioxide) needs to be taken into account. Most of the oceanic carbon dioxide is present as carbonate and bicarbonate, and because of the peculiar buffer mechanism of sea water they do not have alvery large quantitative effect on the partition between the sea and the a1r. The Table shows if sources other than fossil fuel combustion had contributed much carbon dioxide to the air Within the last few decades, APPENDIX Y4 131 the biosphere would have increased in size by what is probably an observable amount. Such an increase has not been noted. We can conclude that, at least during the recent past, fossil fuel combustion has been the only signi?cant source of 00:; added to the ocean-atmosphere- biOSphere system. The available data do not rule out the possibility that in earlier decades carbon dioxide may have come from oxidation of ma- rine or terrestrial humus, as well as from fossil fuels, but if so, more than half of the amount produced was re?absorbed in the biosphere and the ocean. REFERENCES Arrhenius, Svante, 1903: Lehrbuch der kosmischen Physik 2. Leipzig: Hirzel. Bolin, Bert, and Eriksson, Erik, 1958: Changes in the carbon dioxide content of the atmosphere and sea due to fossil fuel combustion. Rossby Memorial Volume, edited by B. Bolin, Rockefeller Institute Press, New York, 1959. pp. 130?142. Bolin, B., and Keeling, G. B., 1963: Large-scale atmospheric mixing as deduced from the seasonal and meridional variations of carbon dioxide. Journal of Geophysical Research, Vol. 68, No. 13. pp. 3899?3920. Broecker, Wallace S. 1963: Cit/012 ratios in surface ocean water. Nuclear Geophysics: Proceedings of conference Publ. 1075, Wash- ington, D.C. pp. 138?149. Broecker, Wallace 8., 1965: Radioisotopes and oceanic mixing. Manuscript Report, Lamont Geological Observatory, Palisades, New York. Brown, Craig W., and Keeling, C. D., 1965: The concentration of atmos- pheric carbon dioxide in Antarctica. Manuscript submitted for publica~ tion, Scripps Institution of Oceanography. Callendar, G. S., 1938: The arti?cial production of carbon dioxide and its in?uence on temperature. Quarterly journal Royal eteorol. 500., Vol. 64. p. 223. Gallendar, G. 8., 1940: Variations in the amount of carbon dioxide in different air currents. Quarterly journal Royal eteorol. Soc, Vol. 66. p. 395. Callendar, G. 8., 1949: Can carbon dioxide in?uence climate? Weather Vol. 4-. p. 310. Cailendar, G. S., 1961: Temperature ?uctuations and trends over the earth. Quarterly Journal Royal Meteorol. Soc., Vol. 87, No. 371. pp. 1m12. Chamberlin, T. C., 1899: An attempt to frame a working hypothesis of the cause of glacial periods on an atmospheric basis. journal of Geology, Vol. 7. pp. 575, 667, 751. Conservation Foundation, 1963: Report of conference on rising carbon dioxide content of the atmosphere. Craig, Harmon, 1957: The natural distribution of radiocarbon and the exchange time of carbon dioxide between atmosphere and sea. Tellus, Vol.9, No. 1. pp. 1?17. 132 RESTORING THE QUALITY OF OUR ENVIRONMENT Eriksson, Erik, 1963: The role of the sea in the circulation of carbon dioxide in nature. Paper submitted to Conservation Foundation Confer- ence, March 12, 1963. Eriksson, Erik, 1963: Possible ?uctuations in atmospheric carbon dioxide due to changes in the properties of the sea. journal of Geophysical Re- search, Vol. 68, N0. 13. pp. 3871?3876. . Hubbert, M. King, 1962: Energy resources; a report to the committee on natural resources of the National Academy of Sciences?National Re- search Council. Publication National Academy of Sciences?? National Research Council, Washington, D.C. - Kaplan, Lewis D., 1959: The in?uence of carbon dioxide variations on the atmospheric heat balance. Tellus, Vol. 12 (1960), No. 2. pp. 204?208. Kraus, E. 13., 1963: Physical aspects of deduced and actual climatic change. Annals of New York Academy (of Sciences, Vol. 95. pp. 225?234. Lamb, H. H., and Johnson, A. I., 1959: Climatic variation and observed changes in the general circulation. Geogra?ska Annaler, Vol. 41. pp. 941?134. Lamb, H. H., and Johnson, A. I., 1961: Climatic variation and observed changes in the general circulation. Geogra?ska Annaler, Vol. 43. pp. 363?400. 3 Lieth, Helmut, 1963: The role of vegetation in the carbon dioxide content of the atmosphere. journal of Geophysical Research, Vol. 68, No. 13. pp. 3887?3898. Lysgaard, L., 1963: On the climatic variation. Changes of Climate, Rome . Symposium by Published in Arid Zone Research Volumes, 20, Paris. pp. 151M159. Manabe, Syukuro, and Strickler, Robert F., 1964: Thermal equilibrium of the atmosphere with a convective adjustment. journal of Atmospheric Sciences, Vol. 21, No. 4. pp. 361?385. Manabe, Syukuro, 1965: Dependence of the climate of the earth?s atmos- phere on the change of the content of some atmospheric absorbers. Text of talk made at summer study session of NAS Panel on Weather and Climate Modi?cation. Mitchell J. Murray, Jr., 1963: Recent secular changes of global tempera- ture. Annals of New York Academy of Sciences, Vol. 95. pp. 235?250. Mitchell, J. Murray, Jr., 1963: On the world-wide pattern of secular tern- perature change. Changes of Climate, Rome Symposium by Published in Arid Zone Research Volumes, 20, Paris. pp. 161? . 181. Maller, F., 1963: On the in?uence of changes in the C02 concentration in air on the radiation balance of the earth?s surface and on the climate. Journal of Geophysical Research, Vol. 68, No. 13. pp. 3877?3886. Pales, Jack C., and Keeling, C. D., 1965: The concentration of atmospheric carbon dioxide in Hawaii. Manuscript submitted for publication, Scripps Institution of Oceanography. Plass, Gilbert N., 1955: The carbon dioxide theory of climatic change. Tellus, Vol.8 (1956), No. 2. pp. 140?154. APPENDIX Y4 133 Plass, Gilbert N., 1956: The in?uence of the 15p. carbon-dioxide band on the atmospheric infra-red cooling rate. Quarterly journal Royal Mere? orol. Soc., Vol. 82. pp. 310?324. Plass, Gilbert N., 1961: Letter to the editor concerning ?The in?uence of carbon dioxide variations on the atmospheric heat balance,? by L. D. Kaplan, Tellus, V01. 12 (1960) pp. 204?208. Tellus, Vol. 13 (1961), No. 2. pp. 296?300. Revelle, Roger, and Suess, Hans E., 1956: Carbon dioxide exchange between atmosphere and ocean and the question of an increase of atmospheric C02 during the past decades. Tellas, Vol. 9 (1957) No. 1. pp. 13?27. Suess, H. E., 1965: Secular variation of the cosmic ray-produced carbon?14: in the atmosphere and their interpretations. Submitted for publication to journal of Geophysical Research, Scripps Institution of Oceanography. United Nations Department of Economic and Social Affairs: World energy requirements 'in 1975 and 2000. Proceedings of the International Con- ference on the Peaceful Uses of Atomic Energy, 1956. pp. 3?33. United Nations, 1961?64?: World energy supplies. Statistical Papers, Series J. United Nations, New York. 7192?122