Global Climate and Ecosystem Change

Global Climate and Ecosystem Change

NA TO ASI Series Advanced Science Institutes Series A series presenting the results of activities sponsored by the NATO Science Committee, which aims at the dissemination of advanced scientific and technological knowledge, with a view to strengthening links between scientific communities. The series is published by an international board of publishers in conjunction with the NATO Scientific Affairs Division A B C o E F G H Life Sciences Physics Mathematical and Physical Sciences Behavioral and Social Sciences Applied Sciences Computer and Systems Sciences Ecological Sciences Cell Biology Plenum Publishing Corporation New York and London Kluwer Academic Publishers Dordrecht, Boston, and London Springer-Verlag Berlin, Heidelberg, New York, London, Paris, and Tokyo Recent Volumes in this Series Volume 234-Constructive Quantum Field Theory II edited by G. Velo and A. S. Wightman Volume 235-Disorder and Fracture edited by J. C. Charmet, S. Roux, and E. Guyon Volume 236-Microscopic Simulations of Complex Flows edited by Michel Mareschal Volume 237-New Trends in Nonlinear Dynamics and Pattern-Forming Phenomena: The Geometry of Nonequilibrium edited by Pierre Coullet and Patrick Huerre Volume 238-Physics, Geometry, and Topology edited by H. C. Lee Volume 239-Kinetics of Ordering and Growth at Surfaces edited by Max G. Lagally Volume 240-Global Climate and Ecosystem Change edited by Gordon J. MacDonald and Luigi Sertorio Volume 241-Applied Laser Spectroscopy edited by Wolfgang Demtroder and Massimo Inguscio Series B: PhysiCS

Global Climate and Ecosystem Change Edited by Gordon J. MacDonald University of California, San Diego La Jolla, California and Lu ig i Sertorio University of Turin Turin, Italy Springer Science+Business Media, LLC

Proceedings of a NATO Advanced Research Workshop on Model Ecosystems and Their Changes, held September 4-8,1989, in Maratea, Italy Library of Congress Cataloging-in-Publication Data NATO Advanced Research Workshop en Model Ecosystems and Their Changes (1989 : Maratea, Italy) Global climate and ecosystem change / edited by Gordon J. MacDonald and Luigi Sertorio. p. cm. (NATO ASI series. Series B, Physics ; vol. 240) "Published in cooperation with NATO Scientific Affairs Division." Includes bibliographical references and index. ISBN 978-1-4899-2485-8 1. Climatic changes Congresses. 2. Ecology Congresses. I. MacDonald, Gordon J. (Gordon James), date. II. Sertorio, Luigi, 1933-. III. North Atlantic Treaty Organization. Scientific Affairs Division. IV. Title. V. Series: NATO ASI series. Series B, Physics ; v. 240. QC991.8.C5N36 1989 574.5'222 dc20 90-47793 C:P 1990 Springer Science+Business Media New York Originally published by Plenum Press, New York in 1990 Softcover reprint of the hardcover 1st edition 1990 All rights reserved No part of this book may be reproduced, stored in a retrieval system, or transmitted in any form or by any means, electronic, mechanical, photocopying, microfilming, recording, or otherwise, without written permission from the Publisher ISBN 978-1-4899-2485-8 DOI 10.1007/978-1-4899-2483-4 ISBN 978-1-4899-2483-4 (ebook)

SPECIAL PROGRAM ON CHAOS, ORDER, AND PATTERNS This book contains the proceedings of a NATO Advanced Research Workshop held within the program of activities of the NATO Special Program on Chaos, Order, and Patterns. Volume 208-MEASURES OF COMPLEXITY AND CHAOS edited by Neal B. Abraham, Alfonso M. Albano, Anthony Passamante, and Paul E. Rapp Volume 225-NONLINEAR EVOLUTION OF SPATIO-TEMPORAL STRUCTURES IN DISSIPATIVE CONTINUOUS SYSTEMS edited by F. H. Busse and L. Kramer Volume 235-DISORDER AND FRACTURE edited by J. C. Charmet, S. Roux, and E. Guyon Volume 236-MICROSCOPIC SIMULATIONS OF COMPLEX FLOWS edited by Michel Mareschal Volume 240-GLOBAL CLIMATE AND ECOSYSTEM CHANGE edited by Gordon J. MacDonald and Luigi Sertorio

PREFACE Humankind's ever-expanding activities have caused environmental changes that reach beyond localities and regions to become global in scope. Disturbances to the atmosphere, oceans, and land produce changes in the living parts of the planet, while, at the same time, alterations in the biosphere modify the atmosphere, oceans, and land. Understanding this complex web of interactions poses unprecedented intellectual challenges. The atmospheric concentrations of natural trace gases-carbon dioxide (C0 2), methane (CH.), nitrous oxide (N 20), and lower-atmosphere ozone (Os)-have increased since the beginning of the industrial revolution. Industrial gases such as the chlorofluorocarbons (CFCs), which are not part of the natural global ecosystem, are increasing at much greater rates than are the naturally occurring trace gases. All these gases absorb and emit infrared radiation and thus have the potential for altering global climate. The major terrestrial biomes are also changing. Although world attention has focused on deforestation, particularly in tropical areas, the development of agriculture, the diversion of water resources, and urbanization have all modified terrestrial ecosystems in both obvious and subtle ways. The terrestrial biosphere, by taking up atmospheric carbon dioxide, acts as a primary determinant of the overall carbon balance of the global ecosystem. Although the ways in which the biosphere absorbs carbon are, as yet, poorly understood, the destruction (and regrowth) of forests certainly alter this process. Significant changes of the marine system on a global scale are less well documented, but it has been clearly demonstrated that man-made pollutants are invading even the deep sea, with inevitable implications for climate. Climate change and ecosystem response were the topics of a NATO Advanced Research Workshop conducted at Maratea, Italy, September 4-10, 1989, that attempted to bring together the two most active fields of research: climate dynamics and ecosystem change. Within the two main themes of the workshop, modeling and predictability received special attention. In both climate and ecosystem change, tension exists between those who advocate models that attempt to include all potentially relevant processes and those who believe that simplified representations can capture the essential elements of the dominant processes. Models in both fields can rapidly become so complex that their behavior is as difficult to understand as the real systems they are intended to depict, and cascading uncertainties undermine efforts to make predictions. While it is clear that atmospheric concentrations of important greenhouse gases are changing, the links between compositional variations, climate, and ecosystem behavior remain a mystery. The difficulty in prediction arises partly from imperfect knowledge about key variables, but also from the fundamental nonlinear nature of climatic and ecological systems. vii

The opening chapter by G. MacDonald provides an overview of what is known and not known about climate systems. Insight into future climate change can be obtained by examining past climate regimes and the conditions that fostered them. However, an underlying problem in understanding past climate and possible future change is disentangling the intrinsic natural variability of the system (due to its nonlinear character) from the effects of imposed, external forcings. Ice age climate exhibits synchrony with orbital fluctuations as well as with variations in atmospheric composition. What part of ice age climate change was due to celestial mechanics, and what part was due to internal changes in the global ecosystem? The same question applies to current and future climate. Available data strongly indicate that global average temperatures have increased by about 0.5 C over the past century, but it is not possible to conclude decisively that this increase is due to changes in atmospheric composition. D. Hartmann reviews the traditional approach to numerical modeling of climate in the second chapter. This approach assumes that the climate of the earth can be modeled using both explicit physics equations for processes that occur on the scale of the model grid resolution (greater than 100 km in the horizontal dimension) and simplified parameterization for processes that take place over shorter distances. These models reproduce features such as seasonal changes in surface temperature, but the question of "tuning" the free parameters to achieve agreement remains controversial. Terrestrial ecosystems playa major role in fixing the carbon cycle and thus determine one of the major feedbacks to climate change. In Chapter 3, M. Crawley argues that changes in vegetation not only affect the carbon balance but also directly influence such climate parameters as albedo, surface roughness, and evapotranspiration. By contrast, the oceans provide a major sink for carbon introduced into the atmosphere by the burning of fossil fuels and by deforestation. The driving force moving carbon from the atmosphere into the oceans is the difference in partial pressures of CO 2 Biological activity reduces the partial pressure of CO 2 in the surface layer by removing carbon detritus through gravitational action and vertical mixing. The oceans also provide a sink for heat and thus slow the warming of the atmosphere. J. McGlade examines certain responses of the ocean biota to climate change in Chapter 4. In Chapter 5, H. Abarbanel returns to some of the issues that were raised in Chapter 1 concerning the nonlinear behavior of climate. The principal issue addressed in this chapter is how to analyze a time series generated by nonlinear processes. The discussion examines current views of chaotic systems whose deterministic structures are revealed by analysis of the underlying strange attractor. The emphasis on analysis of large complex systems is continued in two Appendices by A. Trevisan and B. Andresen that summarize the seminars they presented at Maratea. Acknowledgments The workshop, under the direction of Luigi Sertorio, was supported by grants from NATO and by the Istituto Nazionale Fisica Nucleare (INFN). Preparation of the proceedings was supported by The MITRE Corporation. The manuscripts of the papers came from diverse sources and required heavy editing, for which Margaret Jennings, Malinda Kerr, and lone Swenson deserve deep appreciation. Thanks are also due to Dorothy Oliver for preparing various drafts of the manuscript. Luigi Sertorio Torino, Italy Gordon MacDonald McLean, Virginia USA viii

CONTENTS CLIMATE DYNAMICS Global Climate Change... 1 G.J. MacDonald Modeling Climate Change... 97 D.L. Hartmann ECOSYSTEM CHANGE The Responses of Terrestrial Ecosystems to Global Climate Change M.J. Crawley The Impact of Global Climate Change on Marine Ecosystems J.M. McGlade 141 165 NONLINEAR SYSTEM ANALYSIS Prediction in Chaotic Nonlinear Systems: Time Series Analysis for Aperiodic Evolution... 185 H.D.I. Abarbanel The Use of Simulated Annealing to Solve Extremely Large and Complex Problems... 239 B. Andresen Predictability and Dimensionality of a Simplified Atmospheric Model... 243 A. Trevisan Index... 245 ix