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Committee on the
Importance of Deep-Time Geologic Records for
Understanding Climate Change Impacts
Board on Earth Sciences and Resources
Division on Earth and Life Studies
THE NATIONAL ACADEMIES PRESS
Washington, D.C.
www.nap.edu
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THE NATIONAL ACADEMIES PRESS 500 Fifth Street, N.W. Washington, DC 20001
NOTICE: The project that is the subject of this report was approved by the Gov-
erning Board of the National Research Council, whose members are drawn from
the councils of the National Academy of Sciences, the National Academy of Engi -
neering, and the Institute of Medicine. The members of the committee responsible
for the report were chosen for their special competences and with regard for ap -
propriate balance.
This study was supported by the National Science Foundation under Grant No.
EAR-0625247, the U.S. Geological Survey under Award No. 06HQGR0197, and the
Chevron Corporation. The opinions, findings, and conclusions or recommenda -
tions contained in this document are those of the authors and do not necessarily
reflect the views of the National Science Foundation, the U.S. Geological Survey,
or the Chevron Corporation.
International Standard Book Number-13: 978-0-309-20915-1
International Standard Book Number-10: 0-309-20915-3
Library of Congress Control Number: 2011930581
Additional copies of this report are available from the National Academies Press,
500 Fifth Street, N.W., Lockbox 285, Washington, DC 20055; (800) 624-6242 or (202)
334-3313 (in the Washington metropolitan area); Internet www.nap.edu
Cover: Cover design by Michael Dudzik.
Copyright 2011 by the National Academy of Sciences. All rights reserved.
Printed in the United States of America
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The National Academy of Sciences is a private, nonprofit, self-perpetuating
society of distinguished scholars engaged in scientific and engineering research,
dedicated to the furtherance of science and technology and to their use for the
general welfare. Upon the authority of the charter granted to it by the Congress
in 1863, the Academy has a mandate that requires it to advise the federal govern-
ment on scientific and technical matters. Dr. Ralph J. Cicerone is president of the
National Academy of Sciences.
The National Academy of Engineering was established in 1964, under the charter
of the National Academy of Sciences, as a parallel organization of outstanding en -
gineers. It is autonomous in its administration and in the selection of its members,
sharing with the National Academy of Sciences the responsibility for advising the
federal government. The National Academy of Engineering also sponsors engi -
neering programs aimed at meeting national needs, encourages education and
research, and recognizes the superior achievements of engineers. Dr. Charles M.
Vest is president of the National Academy of Engineering.
The Institute of Medicine was established in 1970 by the National Academy of
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tute acts under the responsibility given to the National Academy of Sciences by its
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V. Fineberg is president of the Institute of Medicine.
The National Research Council was organized by the National Academy of Sci-
ences in 1916 to associate the broad community of science and technology with the
Academy’s purposes of furthering knowledge and advising the federal govern -
ment. Functioning in accordance with general policies determined by the Acad -
emy, the Council has become the principal operating agency of both the National
Academy of Sciences and the National Academy of Engineering in providing
services to the government, the public, and the scientific and engineering com -
munities. The Council is administered jointly by both Academies and the Institute
of Medicine. Dr. Ralph J. Cicerone and Dr. Charles M. Vest are chair and vice chair,
respectively, of the National Research Council.
www.national-academies.org
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COMMITTEE ON THE IMPORTANCE OF DEEP-TIME GEOLOGIC
RECORDS FOR UNDERSTANDING CLIMATE CHANGE IMPACTS
ISABEL P. MONTAÑEZ, Chair (2010-2011), University of California, Davis
RICHARD D. NORRIS, Chair (2007-2009), Scripps Institution of
Oceanography, San Diego, California
THOMAS ALGEO, University of Cincinnati, Ohio
MARK A. CHANDLER, Columbia University, New York
KIRK R. JOHNSON, Denver Museum of Nature and Science, Colorado
MARTIN J. KENNEDY, University of Adelaide, South Australia
DENNIS V. KENT, Rutgers, The State University of New Jersey, Piscataway
JEFFREY T. KIEHL, National Center for Atmospheric Research, Boulder,
Colorado
LEE R. KUMP, The Pennsylvania State University, University Park
A. CHRISTINA RAVELO, University of California, Santa Cruz
KARL K. TUREKIAN, Yale University, New Haven, Connecticut
Liaison from the Board on Earth Sciences and Resources
KATHERINE H. FREEMAN, The Pennsylvania State University,
University Park
National Research Council Staff
DAVID A. FEARY, Study Director
NICHOLAS D. ROGERS, Research Associate
JENNIFER T. ESTEP, Financial and Administrative Associate
COURTNEY R. GIBBS, Program Associate
ERIC J. EDKIN, Senior Program Assistant
v
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BOARD ON EARTH SCIENCES AND RESOURCES
CORALE L. BRIERLEY, Chair, Brierley Consultancy LLC, Denver, Colorado
KEITH C. CLARKE, University of California, Santa Barbara
DAVID J. COWEN, University of South Carolina, Columbia
WILLIAM E. DIETRICH, University of California, Berkeley
ROGER M. DOWNS, The Pennsylvania State University, University Park
JEFF DOZIER, University of California, Santa Barbara
WILLIAM. L. GRAF, University of South Carolina, Columbia
RUSSELL J. HEMLEY, Carnegie Institution of Washington,
Washington, D.C.
MURRAY W. HITZMAN, Colorado School of Mines, Golden
EDWARD KAVAZANJIAN, Jr., Arizona State University, Tempe
ROBERT B. McMASTER, University of Minnesota, Minneapolis
M. MEGHAN MILLER, UNAVCO, Inc., Boulder, Colorado
ISABEL P. MONTAÑEZ, University of California, Davis
CLAUDIA INÉS MORA, Los Alamos National Laboratory, New Mexico
BRIJ M. MOUDGIL, University of Florida, Gainesville
CLAYTON R. NICHOLS, Idaho National Engineering and
Environmental Laboratory (retired), Ocean Park, Washington
HENRY N. POLLACK, University of Michigan, Ann Arbor
JOAQUIN RUIZ, University of Arizona, Tucson
PETER M. SHEARER, University of California, San Diego, La Jolla
REGINAL SPILLER, Allied Energy, Texas
RUSSELL E. STANDS-OVER-BULL, Anadarko Petroleum Corporation,
Billings, Montana
TERRY C. WALLACE, Jr., Los Alamos National Laboratory, New Mexico
National Research Council Staff
ANTHONY R. De SOUZA, Director
ELIZABETH A. EIDE, Senior Program Officer
DAVID A. FEARY, Senior Program Officer
ANNE M. LINN, Senior Program Officer
MARK D. LANGE, Program Officer
SAMMANTHA L. MAGSINO, Program Officer
JENNIFER T. ESTEP, Financial and Administrative Associate
NICHOLAS D. ROGERS, Financial and Research Associate
COURTNEY R. GIBBS, Program Associate
JASON R. ORTEGO, Research Associate
ERIC J. EDKIN, Senior Program Assistant
CHANDA IJAMES, Program Assistant
vi
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Preface
The drive to better understand how Earth’s climate has responded to
natural and anthropogenic forcing over the geologically recent past has
resulted in a plethora of observational and modeling paleoclimate studies
seeking to understand climate dynamics associated with glacial and inter-
glacial cyclicity. From these near-time paleoclimate studies the scientific
community has developed a refined understanding of the complex—and
often nonlinear—dynamics of the Earth’s climate system and has delin -
eated an array of environmental and ecological impacts that have accom -
panied climate change over the past few thousands to hundreds of thou-
sands of years. The knowledge gleaned from this near-time archive has
been of great importance for predicting Earth’s immediate future climate.
There is, however, a growing appreciation by the scientific community that
the changes observed over the past few decades may lead to a degree of
warming and associated climate, resource, and ecological changes well
beyond those of the “icehouse” climate state in which humans evolved
and currently live. Critical insights to understanding such changes are
contained in the deep-time geological record that captures the response of
the climate system to the full spectrum of internal and external forcings,
and their feedbacks, experienced over Earth history.
There is little dispute within the scientific community that humans are
changing Earth’s climate on a decadal to century timescale. This change,
however, is happening within the context of geological time and geological
magnitude, and thus must be evaluated and understood at a comparable
scale. The fossil fuel CO2 released to the atmosphere by humans will
impact the climate system for tens to hundreds of thousands of years,
vii
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viii PREFACE
because of the timescales over which the natural feedbacks in the climate
system sweep CO2 from the atmosphere. Consequently, the changes to the
hydrosphere, cryosphere, chemosphere, and biosphere that are occurring
now and projected within this century could pale in comparison to those
that are possible over the next few centuries. Furthermore, it is studies of
deep-time climates that have revealed the nature of the complex network
of short- and long-term processes and feedbacks that govern the global cli-
mate system. Perhaps more importantly, these studies have also revealed
the potential for positive feedbacks that typically operate on century to
millennial timescales but may become operative on much shorter, human
timescales with continued warming. There are important lessons to be
learned from the repeated inability of existing climate models to recre-
ate the large changes in global temperature distributions and climates
that can be deciphered from deep-time records of past climates that were
much different than Earth’s current glacial state. Despite its potential, the
deep-time geological record is undertapped scientifically, particularly
because it hosts the only records of major, and at times rapid, transitions
across climate states as well as records of past warming far greater than
witnessed by Earth over the past few tens of millions of years but within
the scope of that projected for our future.
This report is the committee’s collective assessment of both the dem -
onstrated and the underdeveloped potential of the deep-time geological
record to inform us about the dynamics of the global climate system in
response to the spectrum of forcings and conditions under which it has
operated. A large part of our effort was directed toward describing past
climate changes and their impacts on regional climates, water resources,
marine and terrestrial ecosystems, and the cycling of life-sustaining ele -
ments, emphasizing the lessons that have been learned uniquely from
deep-time worlds. While revealing gaps in scientific knowledge of past
climate states, we highlight a range of high-priority scientific issues with
potential for major advances in the scientific understanding of climate
processes. Understanding how the complex network of processes and
feedbacks that make up the global climate system operates at various
timescales—and over the full range of climate variability experienced
through Earth’s history—is a high priority for improving projections of
future climatic conditions and the impacts on the surface systems that
can be anticipated with such change. To that end, we propose a research
agenda—and an implementation strategy to address this agenda—that
builds on the evolving cross- and interdisciplinary nature of deep-time
paleoclimate science.
As the question is increasingly raised as to whether Earth could
return—on a human timescale—to a greenhouse climate analogous to that
of more than 35 million years ago, it is essential that science thoroughly
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ix
PREFACE
understands the mechanisms, triggers, and thresholds of climate change
in past warmer worlds and the associated magnitudes, rates, and impacts
of such change. We hope that the readers of this report share our collective
enthusiasm for the richness and societal relevance of the geological record
and for the exciting opportunities for enhanced knowledge provided by
deep-time paleoclimatology.
The committee would like to thank the National Science Foundation,
the U.S. Geological Survey, and Chevron Corporation for enabling this
report through their financial support and participation in the study pro -
cess. As chair, I would also like to acknowledge the committee members
for the insights they brought to the table and their efforts in translating
a plentitude of knowledge into lucid statements and informative fig-
ures. The process was not always linear and involved crossing multiple
thresholds; but analogous to climate change, we anticipate that the out -
come of the process, this report, will “impact” scientific understanding of
the potential of Earth’s global climate system for change. Study Director
David Feary deserves a special acknowledgment for his tireless effort and
patience, aptitude for skillful persuasion, and wonderful wit—it was a
privilege to work with him. The committee is also grateful for the support
of National Research Council staff members Nicholas Rogers, Courtney
Gibbs, and Eric Edkin.
Isabel Patricia Montañez, Chair
Committee on the Importance of Deep-Time Geologic
Records for Understanding Climate Change Impacts
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Acknowledgments
This report was greatly enhanced by those who made presentations
to the committee at public committee meetings and by the participants
at the open workshop sponsored by the committee to gain community
input—David Beerling, Ray Bernor, Karen Bice, Scott Borg, Gabriel Bowen,
Robert DeConto, Harry Dowsett, Alexey Federov, Chris Fielding, Margaret
Frasier, Linda Gundersen, Bill Hay, Patricia Jellison, H. Richard Lane, Tim
Lyons, Thomas Moore, Paul Olsen, Mark Pagani, Judy Parrish, Martin
Perlmutter, Chris Poulsen, Greg Ravizza, Dana Royer, Nathan Sheldon,
Walt Snyder, Linda Sohl, Lynn Soreghan, Christopher Swezey, Robert
Thompson, Thomas Wagner, Debra Willard, Scott Wing, James Zachos,
and Richard Zeebe. The presentations and discussions at these meetings
provided invaluable input and context for the committee’s deliberations.
The provision of additional text and figures by Ron Blakey, Paul Olsen,
Shanan Peters, Brad Sageman, Lynn Soreghan, Jim Zachos, and Richard
Zeebe is also gratefully acknowledged.
This report has been reviewed in draft form by individuals chosen
for their diverse perspectives and technical expertise, in accordance with
procedures approved by the National Research Council’s Report Review
Committee. The purpose of this independent review is to provide candid
and critical comments that will assist the institution in making its published
report as sound as possible and to ensure that the report meets institutional
standards for objectivity, evidence, and responsiveness to the study charge.
The review comments and draft manuscript remain confidential to protect
the integrity of the deliberative process. We wish to thank the following
individuals for their participation in the review of this report:
xi
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xii ACKNOWLEDGMENTS
Ken Caldeira, Carnegie Institution of Washington, Stanford, California
Christopher R. Fielding, University of Nebraska, Lincoln
Paul E. Olsen, Lamont-Doherty Earth Observatory, Columbia
University, Palisades, New York
Heiko Pälike, National Oceanography Centre, University of
Southampton, United Kingdom
Christopher J. Poulsen, University of Michigan, Ann Arbor
Bradley B. Sageman, Northwestern University, Evanston, Illinois
Linda E. Sohl, NASA Goddard Institute for Space Studies, Columbia
University, New York
Thomas N. Taylor, University of Kansas, Lawrence
Ellen Thomas, Yale University, New Haven, Connecticut
James C. Zachos, University of California, Santa Cruz
Although the reviewers listed above have provided many constructive
comments and suggestions, they were not asked to endorse the conclu -
sions or recommendations nor did they see the final draft of the report
before its release. The review of this report was overseen by William W.
Hay, University of Colorado Museum, and Peter M. Banks, Executive
Office, National Academy of Sciences, Washington, D.C. Appointed by the
National Research Council, they were responsible for making certain that
an independent examination of this report was carried out in accordance
with institutional procedures and that all review comments were carefully
considered. Responsibility for the final content of this report rests entirely
with the authoring committee and the institution.
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Contents
EXECUTIVE SUMMARY 1
SUMMARY 5
1 INTRODUCTION 16
Committee Charge and Scope of This Study, 24
2 LESSONS FROM PAST WARM WORLDS 26
Climate Sensitivity to Increasing CO2 in a Warmer World, 29
Tropical and Polar Climate Stability and Latitudinal
Temperature Gradients in a Warmer World, 33
Hydrological Processes and the Global Water Cycle in a
Warmer World, 36
Sea Level and Ice Sheet Fluctuations in a Warmer World, 40
Expansion of Oceanic Hypoxia in a Warmer World, 45
Biotic Response to a Warmer World, 51
3 CLIMATE TRANSITIONS, TIPPING POINTS, AND
THE POINT OF NO RETURN 63
Icehouse-Greenhouse Transitions, 65
How Long Will the Greenhouse Last? 76
xiii
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xiv CONTENTS
4 DECIPHERING PAST CLIMATES—RECONCILING
MODELS AND OBSERVATIONS 81
Climate Model Capabilities and Limitations, 86
Indicators of Climate Sensitivity Through Time—Proxies for
CO2 and Marine Temperatures, 92
Indicators of Regional Climates, 100
Indicators of Oceanic pH and Redox, 104
5 IMPLEMENTING A DEEP-TIME CLIMATE RESEARCH
AGENDA 106
Elements of a High-Priority Deep-Time Climate Research
Agenda, 107
Strategies and Tools to Implement the Research Agenda, 113
Education and Outreach—Steps Toward a Broader Community
Understanding of Climates in Deep Time, 131
6 CONCLUSIONS AND RECOMMENDATIONS 138
Strategies and Tools to Implement a Deep-Time Climate
Research Agenda, 143
Education and Outreach—Steps Toward a Broader Community
Understanding of Climates in Deep-Time, 146
REFERENCES 149
APPENDIXES
A Committee Biographical Sketches 181
B Workshop Agenda and Participants 185
C Presentations to Committee 192
D Acronyms and Abbreviations 193
