Global Climate and Ecosystem Change

258 Pages·1990·10.384 MB·English

by  Gordon J. MacDonald (auth.), Gordon J. MacDonald, Luigi Sertorio (eds.)

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 Life Sciences Plenum Publishing Corporation
B Physics New York and London
C Mathematical Kluwer Academic Publishers
and Physical Sciences Dordrecht, Boston, and London
o
Behavioral and Social Sciences
E Applied Sciences
F Computer and Systems Sciences Springer-Verlag
G Ecological Sciences Berlin, Heidelberg, New York, London,
H Cell Biology 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 ISBN 978-1-4899-2483-4 (eBook)
DOI 10.1007/978-1-4899-2483-4
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
(C02), methane (CH.), nitrous oxide (N20), 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 CO2• Biological activity reduces the partial pressure of CO2 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 Gordon MacDonald
Torino, Italy 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 141
M.J. Crawley
The Impact of Global Climate Change on Marine Ecosystems 165
J.M. McGlade
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
GLOBAL CLIMATE CHANGE
Gordon J. MacDonald
Vice President and Chief Scientist
The MITRE Corporation
7525 Colshire Drive
McLean, VA 22102, USA
INTRODUCTION
Changes in the composition of earth's atmosphere due to human activities
now dominate changes that occur naturally. Theory which links compositional
change to climate change, together with observations of the atmospheric
compositions and climates of earth's neighboring planets, Venus and Mars,
compels us to consider seriously the possibility that future changes in climate due
to Man's activities will be damaging. This article reviews the scientific evidence
relating to past and present changes in earth's atmospheric composition and
climate, and the evidence for future climate shifts.
Climate change has become a scientifically fashionable subject over the past
decade, partly because of the great public and political interest. Yet despite
increased research activity, controversy abounds: Because the atmosphere is a
chaotic, dynamical system, how can trends in climate be positively detected
against its great natural variability? Has a warming trend actually been detected?
To what extent can nature's recuperative powers overcome imposed alterations in
atmospheric composition? And to what extent can computer models reliably
predict future conditions? These questions illustrate areas in which scientific
disagreement exists today, and where controversy is likely to persist into the
foreseeable future.
In addressing these questions, I will first review the evidence pertaining to
current and past changes in concentrations of gases that have a major influence on
the thermal budget of the atmosphere. Following this, in the third section, I
examine the sources and sinks for these gases. Two factors establish the
anthropogenic origin of increased atmospheric carbon dioxide (C02): the
coincidence of the onset of escalating CO levels and the beginning of the
2
industrial revolution, and the rough balance between the amount of carbon
dioxide emitted as a result of fossil fuel combustion and the increased carbon
dioxide concentration in the atmosphere and ocean. Methane is increasing at a
greater rate than carbon dioxide, but its sources and sinks are poorly understood,
as are the sources for nitrous oxide. Despite numerous observations on ozone
made in support of pollution control programs, the long-term variations in ozone
concentration are poorly determined. On a per molecule basis, the strongest
absorbers of outgoing infrared radiation are chlorofluorocarbons (CFCs). These
compounds have no known natural sources, but atmospheric concentrations of
CFCs continue to increase rapidly, even though some western nations have
imposed controls on their use.