Reflecting Sunlight
Recommendations for Solar Geoengineering
Research and Research Governance
Committee on Developing a Research Agenda and Research Governance
Approaches for Climate Intervention Strategies that Reflect Sunlight tos
Cool Earth
Board on Atmospheric Sciences and Climate
Division on Earth and Life Studies
Committee on Science, Technology, and Law
Policy and Global Affairs
A Consensus Study Report of
THE NATIONAL ACADEMIES PRESS
Washington, DC
www.nap.edu
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This activity was supported by contracts between the National Academy of Sciences and the BAND Foundation, the Christopher Reynolds Foundation, the Department of Energy, the MacArthur Foundation, the National Academy of Sciences’ Arthur L. Day Fund, the National Aeronautics and Space Administration, the National Oceanic and Atmospheric Administration, and the V. Kann Rasmussen Foundation. Any opinions, findings, conclusions, or recommendations expressed in this publication do not necessarily reflect the views of any organization or agency that provided support for the project.
International Standard Book Number-13: 978-0-309-67605-2
International Standard Book Number-10: 0-309-67605-3
Digital Object Identifier: https://doi.org/10.17226/25762
Cover Photo: Lake Fairfax, Reston, Virgina by Quinn S. Jackson.
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Suggested citation: National Academies of Sciences, Engineering, and Medicine. 2021. Reflecting Sunlight:Recommendations for Solar Geoengineering ResearchandResearchGovernance. Washington, DC: The National Academies Press. https://doi.org/10.17226/25762.
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COMMITTEE ON DEVELOPING A RESEARCH AGENDA AND RESEARCH GOVERNANCE APPROACHES FOR CLIMATE INTERVENTION STRATEGIES THAT REFLECT SUNLIGHT TO COOL EARTH
CHRISTOPHER FIELD (NAS) (Chair), Stanford University
WILLIAM W.L. CHEUNG, The University of British Columbia
LISA DILLING, University of Colorado, Boulder
PETER C. FRUMHOFF, Union of Concerned Scientists
HENRY (HANK) T. GREELY, Stanford Law School
MARION E. HOURDEQUIN, Colorado College
JAMES HURRELL, Colorado State University
ANDREW LIGHT, George Mason University and World Resources Institute (until January 2021)
ALBERT LIN, University of California, Davis School of Law
DOUGLAS MacMARTIN, Cornell University
ROBERT McHENRY, Bright Silicon Technologies
JUAN MORENO-CRUZ, University of Waterloo
KATHARINE RICKE, University of California, San Diego
LYNN RUSSELL, Scripps Institution of Oceanography
AMBUJ SAGAR, Indian Institute of Technology, Delhi
PAUL WENNBERG (NAS), California Institute of Technology
National Academies of Sciences, Engineering, and Medicine Staff
LAURIE GELLER, Senior Program Officer, Board on Atmospheric Sciences and Climate
STEVEN KENDALL, Program Officer, Committee on Science, Technology, and Law
KATIE THOMAS, Senior Program Officer, Board on Atmospheric Sciences and Climate (until February 2020)
ANITA EISENSTADT, Program Officer, Board on Science, Technology, and Economic Policy (until February 2020)
AMANDA STAUDT, Senior Director, Board on Atmospheric Sciences and Climate
ANNE-MARIE MAZZA, Senior Director, Committee on Science, Technology, and Law
RACHEL SILVERN, Associate Program Officer, Board on Atmospheric Sciences and Climate
ERIN MARKOVICH, Research Associate, Board on Atmospheric Sciences and Climate (until February 2021)
ROB GREENWAY, Program Associate, Board on Atmospheric Sciences and Climate
MICHAEL HUDSON, Senior Program Assistant/Research Assistant, Board on Atmospheric Sciences and Climate (until April 2020)
BOARD ON ATMOSPHERIC SCIENCES AND CLIMATE
A.R. RAVISHANKARA (NAS) (Chair), Colorado State University
MARY GLACKIN (Vice Chair), The Weather Company, an IBM Business (Ret.)
CYNTHIA S. ATHERTON, Heising-Simons Foundation
CECILIA BITZ, University of Washington
JOHN C. CHIANG, University of California, Berkeley
BRADLEY R. COLMAN, The Climate Corporation
BARTHOLOMEW E. CROES, California Air Resources Board
ROBERT B. DUNBAR, Stanford University
EFI FOUFOULA-GEORGIOU (NAE), University of California, Irvine
PETER C. FRUMHOFF, Union of Concerned Scientists
VANDA GRUBISIC, National Center for Atmospheric Research
EVERETTE JOSEPH, National Center for Atmospheric Research
ROBERT KOPP, Rutgers, The State University of New Jersey
RUBY LEUNG (NAE), Pacific Northwest National Laboratory
JONATHAN MARTIN, University of Wisconsin-Madison
ALLISON STEINER, University of Michigan
DAVID W. TITLEY, U.S. Navy (Ret.), Pennsylvania State University
National Academies of Sciences, Engineering, and Medicine Staff
AMANDA STAUDT, Senior Director
LAUREN EVERETT, Senior Program Officer
SHELLY FREELAND, Financial Business Partner
RITA GASKINS, Administrative Coordinator
LAURIE GELLER, Senior Program Officer
ROB GREENWAY, Program Associate
ERIN MARKOVICH, Research Associate
APRIL MELVIN, Senior Program Officer
AMANDA PURCELL, Senior Program Officer
ALEX REICH, Associate Program Officer
RACHEL SILVERN, Associate Program Officer
COMMITTEE ON SCIENCE, TECHNOLOGY, AND LAW
DAVID BALTIMORE (NAS/NAM) (Co-Chair), California Institute of Technology
DAVID S. TATEL (Co-Chair), U.S. Court of Appeals for the District of Columbia Circuit
JOE S. CECIL, University of California, Berkeley School of Law
ERWIN CHEMERINSKY, University of California, Berkeley School of Law
ELLEN WRIGHT CLAYTON (NAM), Vanderbilt University Medical Center
JOHN S. COOKE, Federal Judicial Center
JOHN DABIRI, California Institute of Technology
JENNIFER EBERHARDT (NAS), Stanford University
FEI-FEI LI (NAE/NAM), Stanford University
JUDITH MILLER, Independent Consultant
MARTHA MINOW, Harvard Law School
KIMANI PAUL-EMILE, Fordham University School of Law
NATALIE RAM, University of Maryland Francis King Carey School of Law
LISA RANDALL (NAS), Harvard University
PAUL M. ROMER, New York University
WILLIAM B. SCHULTZ, Zuckerman Spaeder LLP
JOSHUA SHARFSTEIN (NAM), Johns Hopkins Bloomberg School of Public Health
SUSAN S. SILBEY, Massachusetts Institute of Technology
SRI SRINIVASAN, U.S. Court of Appeals for the District of Columbia Circuit
GREGORY STONE, Munger, Tolles & Olson LLP
SUSAN R. WESSLER (NAS), University of California, Riverside
National Academies of Sciences, Engineering, and Medicine Staff
ANNE-MARIE MAZZA, Senior Director
STEVEN KENDALL, Program Officer
DOMINIC LOBUGLIO, Senior Program Assistant
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Acknowledgments
This Consensus Study Report was reviewed in draft form by individuals chosen for their diverse perspectives and technical expertise. The purpose of this independent review is to provide candid and critical comments that will assist the National Academies of Sciences, Engineering, and Medicine in making each published report as sound as possible and to ensure that it meets the institutional standards for quality, 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 thank the following individuals for their review of this report:
WALEED ABDALATI, University of Colorado Boulder
DONALD C. BINGAMAN, VPE Aerospace Consulting, LLC
DANIEL M. BODANSKY, Arizona State University
TRACY HESTER, University of Houston
SIKINA JINNAH, University of California, Santa Cruz
FRANK N. KEUTSCH, Harvard University
DUNCAN MCLAREN, University of Lancaster
HELENE MURI, Norwegian University of Science and Technology
SIMON NICHOLSON, American University
NICK PIDGEON, Cardiff University
ALAN ROBOCK, Rutgers University
SIMONE TILMES, National Center for Atmospheric Research
DAVID G. VICTOR, University of California, San Diego
KYLE WHYTE, University of Michigan
ROBERT WOOD, University of Washington
Although the reviewers listed above provided many constructive comments and suggestions, they were not asked to endorse the conclusions or recommendations of this report nor did they see the final draft before its release. The review of this report was overseen by Antonio J. Busalacchi (NAE), University Corporation for Atmospheric Research, and Andrew R. Solow, Woods Hole Oceanographic Institution. They were responsible for making certain that an independent examination of this report was carried out in accordance with the standards of the National Academies and that all
review comments were carefully considered. Responsibility for the final content rests entirely with the authoring committee and the National Academies.
Preface
In 2015, the National Research Council published a two-volume report that provided a technical evaluation and discussion of the impacts of geoengineering climate. One volume addressed technologies for removing carbon dioxide from the atmosphere. The other explored prospects for cooling the planet by albedo modification—increasing the reflection of solar radiation. A central conclusion from the 2015 study is that the two families of approaches for geoengineering climate differ greatly in terms of scientific understanding, technical feasibility, risks, and societal implications. In particular, understanding of prospects for and issues with albedo modification is nascent. This led that committee to recommend that “albedo modification at scales sufficient to alter climate should not be deployed at this time “ (NRC, 2015, p. 9). Noting that the urgency of the climate crisis underscores the importance of understanding the full range of options, however, the committee also recommended a program of further research on albedo modification and the development of a framework for governing that research.
Since 2015, the motivation for understanding the full range of options for dealing with the climate crisis has gotten even stronger. Globally, 2015–2019 were the 5 warmest years in the instrumental record. Understanding of the link between warming and extreme heat, wildfires, drought, hurricanes, and diverse socioeconomic impacts is stronger than ever. As I write this in September 2020, my home in California’s Bay Area is experiencing record-breaking temperatures and has been blanketed with wildfire smoke for more than 3 weeks. But despite overwhelming evidence that the climate crisis is real and pressing, emissions of greenhouse gases continue to increase, with global emissions of fossil carbon dioxide rising 10.8 percent from 2010 through 2019. The total for 2020 is on track to decrease in response to decreased economic activity related to the COVID-19 pandemic. The pandemic is thus providing frustrating confirmation of the fact that the world has made little progress in separating economic activity from carbon dioxide emissions.
The creation of this study committee is one response to the need for understanding the full range of options for dealing with the climate crisis. Its mandate flows directly from the recommendations of the 2015 report but with an urgency reinforced by the world’s slow progress on climate. The undertaking of this report should not, however, be interpreted as an indication of giving up on decarbonization. Rapidly reducing emissions of carbon dioxide and other greenhouse gases remains a top priority, as
explicitly recommended in the 2015 report. Throughout the committee’s discussions, the focus was always on evaluating whether and how, in the context of a global emphasis on emissions reductions and carbon dioxide removal, other approaches might be explored.
The committee that carried out this study was remarkably diverse. With expertise ranging from atmospheric chemistry to philosophy and experiences ranging from space-based and airborne measurement campaigns to global climate negotiations, all of us needed to make real investments in stepping outside our communities and learning the language and perspectives of colleagues from very different backgrounds. Committee members arrived with a wide array of thoughts not only about the topic but also about the best path forward for building knowledge. Often, there was as much discussion about who needs to be in the conversation as there was about the design and oversight of a research program. I greatly admire the willingness of every member of the committee to explain and defend but also challenge their own perspectives.
Chris Field, Chair
Dedication
This report is dedicated to Paul J. Crutzen (1933-2021) and Steve Rayner (1953–2020).
Paul Crutzen and Steve Rayner were pioneering researchers, widely recognized for diverse contributions. Both made foundational contributions to solar geoengineering scholarship.
Paul Crutzen was, more than anything, a student of human impacts on Earth. He was a meteorologist best known for his research on stratospheric ozone depletion, work that earned him the 1995 Nobel Prize in Chemistry. Crutzen’s coining of the term “Anthropocene” underscores the focus of his scholarship on impacts. His 2006 essay on solar geoengineering set the stage for future discussions in stark, memorable terms, laying out the risks from climate disruption, the challenges of decarbonization, and the pros and cons of solar geoengineering.
Steve Rayner, who called himself an “undisciplined” scholar, made major contributions to the understanding of how science and technology shape the relationship between societies and nature. Much of his focus was on the social science of addressing climate change. Deeply interested in the role of science in governance and the governance of science, Rayner was a strong proponent of ambitious action on climate but a harsh critic of the Kyoto Protocol. He established much of the framework for thinking about governance of solar geoengineering, especially through his role as lead author of the Oxford Principles for Geoengineering Governance.
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Contents
1.2 Scope and Motivation of This Report
1.3 Solar Geoengineering Is Not a Substitute for Mitigation
2 Assessment of the Current Solar Geoengineering Research and Research Governance Landscape
2.1 Overview of Proposed Solar Geoengineering Methods
2.2 Natural Sciences and Technology Dimensions
2.4 Synthesis of Research Assessment
2.5 Current Mechanisms for Research Governance
3.1 Enabling Future Decision Makers
3.2 Societal Context for Solar Geoengineering Research
3.3 Intersecting Dimensions of Research, Society, and Research Governance
3.4 Principles for Solar Geoengineering Research and Research Governance
4. A Solar Geoengineering Research Program: Goals and Approach
4.2 Goals and Attributes of a Solar Geoengineering Research Program
4.3 Capacity Needed to Advance Solar Geoengineering Research and Research Governance
4.4 Federal Agency Participation and Coordination
4.5 Roles for Philanthropic Support
5.2 National/Domestic Research Governance
5.3 International Research Governance
6. An integrated Agenda for Solar Geoengineering Research
6.1 High-Level Framing for the Research Agenda
6.2 The Research Agenda Topics
6.3 Outdoor Solar Geoengineering Experimentation
6.4 Funding Considerations for Solar Geoengineering Research
B Speakers from the Committee Meetings & Webinars
C Scenarios Developed By The Committee for the “Decision Maker Needs” Webinars