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The Polar Regions and Climatic Change Appendix Committee on the Role of the Polar Regions in Climatic Change Polar Research Board Commission on Physical Sciences, Mathematics, and Resources National Research Council It NAS-NAE NATIONAL ACADEMY PRESS Washington, D.C. 1984 j\if)\/ ' LIBRARY
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. The members of the committee responsible for the report were chosen for their special competences and with regard for appropriate balance. 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. The National Research Council was established by the National Academy of Sciences in l9l6 to associate the broad community of science and technology with the Academy's purposes of furthering knowledge and of advising the federal government. The Council operates in accordance with general policies determined by the Academy under the authority of its congressional charter of l863, which establishes the Academy as a private, nonprofit, self-governing membership corporation. The Council has become the principal operating agency of both the National Academy of Sciences and the National Academy of Engineering in the conduct of their services to the government, the public, and the scientific and engineering communities. It is administered jointly by both Academies and the Institute of Medicine. The National Academy of Engineering and the Institute of Medicine were established in l964 and l970, respectively, under the charter of the National Academy of Sciences. Preparation of this report was made possible by a grant from the Andrew W. Mellon Foundation to the Polar Research Board and by the continuing support provided to the Board by the Office of Naval Research, the National Oceanic and Atmospheric Administration, and the Department of Energy. Copies available in limited quantity from Polar Research Board 2l0l Constitution Avenue, N.W. Washington, D.C. 204l8
Committee on the Role of the Polar Regions in Climatic Change J. Murray Mitchell, Jr., National Oceanic and Atmospheric Administration, Cochairman William W. Kellogg, National Center for Atmospheric Research, Boulder, Cochairman 0. James Baker, Jr., Department of Oceanography, University of Washington Roger G. Barry, World Data Center-A for Glaciology, University of Colorado Charles R. Bentley, Department of Geology and Geophysics, University of Wisconsin George H. Denton, Department of Geological Sciences, University of Maine Joseph O. Fletcher, National Oceanic and Atmospheric Administration, Boulder W. Lawrence Gates, Department of Atmospheric Sciences, Oregon State University James D. Hays, Lament-Donerty Geological Observatory, Columbia University Terence J. Hughes, Department of Geological Sciences, University of Maine John Imbrie, Department of Geological Sciences, Brown University Chester C. Langway, Department of Geological Sciences, State University of New York at Buffalo John H. Mercer, Institute of Polar Studies, The Ohio State University Troy L. P6w6, Department of Geology, Arizona State University Uwe Radok, Cooperative Institute for Research and Environmental Sciences, University of Colorado, Boulder Norbert Untersteiner, Polar Science Center, University of Washington iii
Polar Research Board Charles R. Bentley, Geophysical and Polar Research Center, University of Wisconsin, Chairman W. Lawrence Gates, Department of Atmospheric Sciences, Oregon State University Ben C. Gerwick, Jr., Department of Civil Engineering, University of California, Berkeley Richard M. Goody, Division of Engineering and Applied Physics, Harvard University Arnold L. Gordon, Lamont-Doherty Geological Observatory, Columbia University Hans O. Jahns, EXXON Production Research Company, Houston Philip L. Johnson, John E. Gray Institute, Lamar University Arthur H. Lachenbruch, U.S. Geological Survey, Menlo Park Louis J. Lanzerotti, AT&T Bell Laboratories Chester M. Pierce, Harvard University Juan G. Roederer, Geophysical Institute, University of Alaska Robert H. Rutford, University of Texas at Dallas John H. Steele, Woods Hole Oceanographic Institution Ian Stirling, Canadian Wildlife Service, Edmonton, Alberta Cornelius W. Sullivan, Department of Biological Sciences, University of Southern California Ex Officio Jerry Brown, Committee on Permafrost, Chairman Mark F. Meier, Committee on Glaciology, Chairman James H. Zumberge, U.S. Delegate to Scientific Committee on Antarctic Research, International Council of Scientific Unions Iv
Agency Liaison Representatives Thomas J. Gross, CO2 Research Program, Department of Energy G. Leonard Johnson, Arctic Programs, office of Naval Research Ned A. Ostenso, National Oceanic and Atmospheric Administration Edward P. Todd, Division of Polar Programs, National Science Foundation Staff W. Timothy Hushen, Staff Director Bertita E. Compton, Staff Officer Muriel Dodd, Administrative Assistant
Commission on Physical Sciences, Mathematics, and Resources Herbert Friedman, National Research Council, Chairman Elkan R. Blout, Department of Biological Chemistry, Harvard Medical School William Browder, Department of Mathematics, Princeton University Bernard F. Burke, Department of Physics, Massachusetts Institute of Technology Herman Chernoff, Department of Mathematics, Massachusetts Institute of Technology Mildred S. Dresselhaus, Department of Electrical Engineering, Massachusetts Institute of Technology Walter R. Eckelmann, Sohio Petroleum Company Joseph L. Fisher, Office of the Governor, Richmond, Virginia James C. Fletcher, School of Engineering, University of Pittsburgh Gerhart Friedlander, Chemistry Department, Brookhaven National Laboratory Edward A. Frieman, Science Applications, Inc., La Jolla, California Edward D. Goldberg, Scripps Institution of Oceanography, University of California, San Diego Charles L. Hosier, Jr., Department of Meteorology, Pennsylvania State University Konrad B. Krauskopf, School of Earth Sciences, Stanford University Charles J. Mankin, Oklahoma Geological Survey Walter H. Munk, Institute of Geophysical and Planetary Physics, University of California, San Diego George E. Pake, Xerox Research Center, Palo Alto Robert E. Sievers, Department of Chemistry, University of Colorado vi
Howard E. Simmons, Jr., Central Research and Development Department, E. I. du Pont de Nemours & Company, Inc. John D. Spengler, Department of Environmental Health Sciences, Harvard School of Public Health Hatten S. Yoder, Jr., Geophysical Laboratory, Carnegie Institution of Washington Raphael G. Rasper, Executive Director Lawrence E. McCray, Associate Executive Director vii
Preface The climate of the Earth is perpetually variable and changing. Uncertainties about future climate, compounded by concerns that the accumulation of carbon dioxide in the atmosphere and other by-products of human activities may bring about inadvertent changes of climate in future decades, place a premium on improved understanding and prediction of climate to meet the needs of modern society. A major goal of climate research now in progress under the aegis of many national and international institutions is to develop a comprehen- sive theory of global climate as a first step to a rational climate prediction capability. Significant progress toward this goal has been achieved in the past decade. In connection with global climate concerns, the polar regions of the Earth have become the focus of considerable attention in view of three distinct yet related circumstances: o Growing evidence that the polar regions play a key role in the physical processes responsible for global climatic fluctuations and in some circumstances may be a prime mover of such fluctuations; o Widening appreciation of the polar regions as a natural repository of information about past climatic fluctuations and about past Earth-environmental events causally related to climatic fluctuations; and o Mounting concerns that future changes of climate, such as the general global-scale warming believed likely to result in future decades and centuries from the accumulation of carbon dioxide and other pollutants in the atmosphere, may disturb the equilibrium of polar ice masses and hence global sea levels. ix
These several matters clearly merit intensive parallel study based on separate research agendas. At the same time, however, the Polar Research Board of the National Research Council (NRC) has perceived a need to address them together in the context of a holistic view of planetary-scale climate, from which perspective the global interconnectedness of climate processes and their social implications is both the unifying theme and the key to setting overall goals and priorities in climate- related polar research. This perspective and its implications for future research are the focus of the report, to which this volume is an appendix. The report was prepared by the Committee on the Role of the Polar Regions in Climatic Change, which was established by the Polar Research Board in l980 to undertake a study in the Board's new "Polar Research - A Strategy" series. The committee's overall findings, conclusions, and recommendations are published in a separate volume. The volume in hand consists of three signed appendixes that together provide much of the background material and documentation considered by the committee in framing those conclusions and recommendations.
Contents APPENDIX A. THE ROLE OF POLAR REGIONS IN CLIMATE DYNAMICS l Internal Factors Affecting Climatic Variations l External Factors Affecting Climatic Variations 2 Polar Processes and Climatic Variations 6 Heat Budget Feedback Mechanisms ll Sea Ice and Climate l3 Climatic Roles of the Polar Ocean l8 Snow and Ice on Land 2l Research Strategies 25 References 28 APPENDIX B. POLAR REGIONS AS WINDOWS ON THE PAST 33 Introduction 33 Sources of Paleoclimatic Information 34 Ocean-floor sediments 35 Glacier ice records 4l Lakes and bogs in the tundra 54 Periglacial features as climatic indicators 62 Tree rings 65 References 70 APPENDIX C. THE POLAR REGIONS: A CONCERN FOR THE FUTURE 77 Response Mechanisms 79 Evidence for Past Changes 85 Natural Changes 90 Human-Induced Changes and Consequences 98 Problems and Research Objectives l06 References.. l08 xi