A Research Agenda Toward Atmospheric Methane Removal (2024)
Chapter: Front Matter
A Research Agenda Toward
Atmospheric Methane Removal
_______
Committee on Atmospheric Methane
Removal: Development of a Research
Agenda
Board on Atmospheric Sciences and
Climate
Board on Chemical Sciences and
Technology
Division on Earth and Life Studies
Board on Energy and Environmental
Systems
Division on Engineering and Physical
Sciences
Consensus Study Report
NATIONAL ACADEMIES PRESS 500 Fifth Street, NW Washington, DC 20001
This activity was supported by a contract between the National Academy of Sciences and the ClimateWorks 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: 978-0-309-70665-0
International Standard Book Number-10: 0-309-70665-3
Digital Object Identifier: https://doi.org/10.17226/27157
Library of Congress Control Number: 2024950505
This publication is available from the National Academies Press, 500 Fifth Street, NW, Keck 360, Washington, DC 20001; (800) 624-6242 or (202) 334-3313; http://www.nap.edu.
Copyright 2024 by the National Academy of Sciences. National Academies of Sciences, Engineering, and Medicine and National Academies Press and the graphical logos for each are all trademarks of the National Academy of Sciences. All rights reserved.
Printed in the United States of America.
Suggested citation: National Academies of Sciences, Engineering, and Medicine. 2024. A Research Agenda Toward Atmospheric Methane Removal. Washington, DC: The National Academies Press. https://doi.org/10.17226/27157.
The National Academy of Sciences was established in 1863 by an Act of Congress, signed by President Lincoln, as a private, nongovernmental institution to advise the nation on issues related to science and technology. Members are elected by their peers for outstanding contributions to research. Dr. Marcia McNutt is president.
The National Academy of Engineering was established in 1964 under the charter of the National Academy of Sciences to bring the practices of engineering to advising the nation. Members are elected by their peers for extraordinary contributions to engineering. Dr. John L. Anderson is president.
The National Academy of Medicine (formerly the Institute of Medicine) was established in 1970 under the charter of the National Academy of Sciences to advise the nation on medical and health issues. Members are elected by their peers for distinguished contributions to medicine and health. Dr. Victor J. Dzau is president.
The three Academies work together as the National Academies of Sciences, Engineering, and Medicine to provide independent, objective analysis and advice to the nation and conduct other activities to solve complex problems and inform public policy decisions. The National Academies also encourage education and research, recognize outstanding contributions to knowledge, and increase public understanding in matters of science, engineering, and medicine.
Learn more about the National Academies of Sciences, Engineering, and Medicine at www.nationalacademies.org.
Consensus Study Reports published by the National Academies of Sciences, Engineering, and Medicine document the evidence-based consensus on the study’s statement of task by an authoring committee of experts. Reports typically include findings, conclusions, and recommendations based on information gathered by the committee and the committee’s deliberations. Each report has been subjected to a rigorous and independent peer-review process and it represents the position of the National Academies on the statement of task.
Proceedings published by the National Academies of Sciences, Engineering, and Medicine chronicle the presentations and discussions at a workshop, symposium, or other event convened by the National Academies. The statements and opinions contained in proceedings are those of the participants and are not endorsed by other participants, the planning committee, or the National Academies.
Rapid Expert Consultations published by the National Academies of Sciences, Engineering, and Medicine are authored by subject-matter experts on narrowly focused topics that can be supported by a body of evidence. The discussions contained in rapid expert consultations are considered those of the authors and do not contain policy recommendations. Rapid expert consultations are reviewed by the institution before release.
For information about other products and activities of the National Academies, please visit www.nationalacademies.org/about/whatwedo.
COMMITTEE ON ATMOSPHERIC METHANE REMOVAL: DEVELOPMENT OF A RESEARCH AGENDA
GABRIELLE DREYFUS (Chair), Institute for Governance & Sustainable Development
HOLLY BUCK, University at Buffalo
HINSBY CADILLO-QUIROZ, Arizona State University
BENJAMIN A. CONVERSE, University of Virginia
FARUQUE HASAN, Texas A&M University
ROBERT B. JACKSON, Stanford University
SIKINA JINNAH, University of California, Santa Cruz
CHRISTOPHER W. JONES (NAE), Georgia Institute of Technology
APRIL LEYTEM, U.S. Department of Agriculture
THOMAS McKONE, University of California, Berkeley
SIMON H. PANG, Lawrence Livermore National Laboratory
JOSÉ G. SANTIESTEBAN (NAE), ExxonMobil Research and Engineering Company (Retired)
LISA Y. STEIN, University of Alberta
ALEX TURNER, University of Washington
KATEY WALTER ANTHONY, University of Alaska Fairbanks
MARGARET WOOLDRIDGE, University of Michigan
Staff
RACHEL SILVERN, Study Director, Board on Atmospheric Sciences and Climate (BASC)
BRENT HEARD, Senior Program Officer, Board on Energy and Environmental Systems
ANNIE MANVILLE, Program Assistant, BASC
LINDSAY MOLLER, Research Associate, BASC
RACHEL SANCHEZ, Senior Program Assistant, BASC (until January 2024)
BOARD ON ATMOSPHERIC SCIENCES AND CLIMATE
BRAD R. COLMAN (Chair), The Climate Corporation (Retired)
JOSEPH ÁRVAI, University of Southern California
CYNTHIA S. ATHERTON, Heising-Simons Foundation
ELIZABETH A. BARNES, Colorado State University
BART E. CROES, California Air Resources Board (Retired)
MINGHUI DIAO, San Jose State University
NEIL DONAHUE, Carnegie Mellon University
LESLEY-ANN DUPIGNY-GIROUX, University of Vermont
EFI FOUFOULA-GEORGIOU (NAE), University of California, Irvine
KEVIN GURNEY, Northern Arizona University
ANDREA LOPEZ LANG, University of Albany
MARIA CARMEN LEMOS (NAS), University of Michigan
ZHANQING LI, University of Maryland
AMY McGOVERN, University of Oklahoma
LINDA O. MEARNS, National Center for Atmospheric Research
JONATHAN A. PATZ (NAM), University of Wisconsin–Madison
KEVIN REED, Stony Brook University
ARADHNA TRIPATI, University of California, Los Angeles
BERNADETTE WOODS PLACKY, Climate Central
Staff
KASEY WHITE, Board Director
KATELYN CREWS, Senior Program Assistant
APURVA DAVE, Senior Program Officer
MORGAN DISBROW-MONZ, Program Officer
KATRINA HUI, Associate Program Officer
ANNIE MANVILLE, Senior Program Assistant
APRIL MELVIN, Senior Program Officer
LINDSAY MOLLER, Research Associate
RACHEL SILVERN, Program Officer
STEVEN STICHTER, Senior Program Officer
BOARD ON CHEMICAL SCIENCES AND TECHNOLOGY
SCOTT COLLICK (Co-Chair), DuPont
JENNIFER S. CURTIS (NAE) (Co-Chair), University of California, Davis
RIGOBERTO CASTILLO ADVINCULA, Oak Ridge National Laboratory
GERARD BAILLELY, Procter & Gamble Company
RUBEN G. CARBONELL (NAE), North Carolina State University
LEO CHIANG (NAE), The Dow Chemical Company
JOHN FORTNER, Yale University
KAREN I. GOLDBERG (NAS), University of Pennsylvania
MARTHA HEAD, Amgen
JENNIFER M. HEEMSTRA, Washington University in St. Louis
JODIE LUTKENHAUS, Texas A&M University
SHELLEY D. MINTEER, University of Utah
AMY PRIETO, Colorado State University
MEGAN L. ROBERTSON, University of Houston
ANUP K. SINGH, Lawrence Livermore National Laboratory
VIJAY SWARUP, ExxonMobil Research and Engineering Company
CATHY TWAY, BP
Staff
CHARLES FERGUSON, Senior Board Director
THANH NGUYEN, Finance Business Partner
LIANA VACCARI, Program Officer
KAYANNA WYMBS, Research Assistant
BOARD ON ENERGY AND ENVIRONMENTAL SYSTEMS
SUE TIERNEY (Chair), Analysis Group
LOUISE BEDSWORTH, University of California, Berkeley, School of Law
T.J. GLAUTHIER, TJG Energy Associates
PAULA GLOVER, Alliance to Save Energy
DENISE GRAY, LG Energy Solution Michigan
JENNIFER R. HOLMGREN (NAE), LanzaTech
JOHN KASSAKIAN (NAE), Massachusetts Institute of Technology
MICHAEL LAMACH, Trane Technologies (Retired)
CARLOS MARTÍN, Harvard University
JOSÉ G. SANTIESTEBAN (NAE), ExxonMobil Research and Engineering Company (Retired)
GORDON VAN WELIE (NAE), ISO New England
DAVID G. VICTOR, University of California, San Diego
Staff
K. JOHN HOLMES, Senior Director and Scholar
JASMINE VICTORIA BRYANT, Research Assistant
REBECCA DEBOER, Research Associate
BRENT HEARD, Senior Program Officer
KASIA KORNECKI, Senior Program Officer
HEATHER LOZOWSKI, Financial Manager
KAIA RUSSELL, Senior Program Assistant
CATHERINE WISE, Program Officer
ELIZABETH ZEITLER, Associate Director
JAMES ZUCCHETTO, Senior Scientist
Reviewers
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:
SARAH BAKER, Lawrence Livermore National Laboratory
SIFANG CHEN, Carbon180
ARLENE FIORE, Massachusetts Institute of Technology
BARUCH FISCHOFF (NAS/NAM), Carnegie Mellon University
TRACY HESTER, University of Houston
ANDREA HICKS, University of Wisconsin-Madison
ANNA-MARIA HUBERT, University of Calgary
ERIC KORT, University of Michigan
NATALIE MAHOWALD, Cornell University
JUAN MORENO-CRUZ, University of Waterloo
SIMON NICHOLSON, American University
CHARLES RICE, Kansas State University
SHUCHI TALATI, Alliance for Just Deliberation on Solar Geoengineering
JULIANA VASCO-CORREA, Pennsylvania State University
JULIE ZIMMERMAN, Yale University
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 MICHAEL PRATHER, University of California, Irvine, and MICHAEL LADISCH (NAE), Purdue University. 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.
Contents
Methane Removal and This Study
2 CHALLENGES IN ADDRESSING METHANE EMISSIONS
Methane Sources, Sinks, and Trends
Interventions Beyond Emissions Mitigation
Policies Advancing Methane Mitigation and Carbon Removals
3 WHY CONSIDER METHANE REMOVAL?
The Case for and Against Methane Removal
Why Consider Atmospheric Methane Removal?
Governance, Public Engagement, Public Perspectives, and Environmental Justice
Policy Landscape for Atmospheric Methane Removal
Costs, Trade-Offs, and Resource Use
Potential Physical Consequences of Atmospheric Methane Removal Technologies
A COMMITTEE MEMBER BIOGRAPHICAL SKETCHES
Preface
“Atmospheric [m]ethane is like the ancient minotaur, dominantly human, partly natural, with more than a whiff of cow breath” (Nisbet, 2023a).
The record-breaking warmth of 2023 may mark a turning point in our understanding and experience of human-induced climate change. The 12-month period of March 2023–February 2024 averaged 1.56°C above the 1850–1900 global surface temperature average (The Copernicus Programme, 2024).1 There are indications that the rate of warming may be accelerating.2 This warming is undoubtedly due to continued burning of fossil fuels and emissions of greenhouse gases, and some suggest that this is a sign that our current understanding and models underestimate the sensitivity of the climate (Hansen et al., 2023, 2024). Regardless, the result is that impacts from climate change are growing and affecting our world today.
Where does methane fit into this moment? While methane has long been known to be a greenhouse gas, it was not high on the agenda of heads of state prior to 2021. As former U.S. Secretary of State John Kerry noted in December 2023 at the 28th Conference of the Parties to the United Nations Framework Convention on Climate Change, none of his counterparts were talking about methane in 2015 when the Paris Agreement was negotiated (Firstpost, 2023). Almost 10 years later, methane is getting far greater attention, with more than 150 countries participating in the Global Methane Pledge, which launched in 2021, and a growing trend toward binding methane regulations.3
___________________
1 This is distinct from crossing 1.5°C of global warming (for a 20-year period), as defined by IPCC (2021).
2 Debate continues on whether acceleration in global mean temperature is detectable (e.g., Foster, 2024; Hausfather, 2024) or not (e.g., Samset et al., 2023; Schmidt, 2024), though these studies do not exclude the possibility of acceleration below the threshold of detection.
Several factors likely contribute to this “methane moment.” The atmospheric concentration of methane has been on the rise since 2007 after a pause in the early 2000s, with dramatic jumps in 2020 and 2021 (Lan et al., 2024). The respective contributions from anthropogenic and natural emissions sources to recent methane concentration increases is a matter of active research, with studies regularly arriving at different conclusions due to the under-constrained information set (e.g., Saunois et al., 2024; Shindell et al., 2024). Previously invisible emissions are increasingly being made visible thanks to a growing suite of land, air, and space-based instruments (e.g., Jacob et al., 2022). Most of the reductions in methane emissions from the oil and gas sector can be done at no to low cost to deliver fast climate and air quality benefits (UNEP & CCAC, 2021). Additionally, as climate attribution science has matured, the growing impacts of global warming are increasingly difficult to ignore, drawing attention to the importance of addressing both near- and longer-term warming (Dreyfus et al., 2022).
The concept of atmospheric methane removal is even newer. It has been 15 years since Yoon et al. (2009) modeled biotrickling filters and Boucher and Folberth (2010) suggested artificial methane removal from the atmosphere or surface waters in the context of mitigating climate change and limiting atmospheric methane concentrations arising from potential strong natural methane feedbacks in a warming world. The concept was further advanced 5 years ago using a framework of atmospheric restoration (Jackson et al., 2019).
While scientists have been raising alarms about the potentially dire consequences of global warming since at least the 1980s, the general sense through the early 2000s was that impacts would not be felt until decades in the future. The notion that it might one day be necessary to remove methane from the atmosphere likely would not have been conceivable in the early 2000s when atmospheric methane concentrations were flat; the general sense was that the impacts of global warming seemed far in the future, and the prospects of reigning in carbon emissions in a timely way appeared daunting but doable (Pacala & Socolow, 2004). Rather than shrink, emissions have continued to grow in the intervening decades, narrowing the path available for staying within a relatively safe climate zone. It is in this context of growing risk, by which mitigation of greenhouse gas emissions alone may be insufficient to keep warming and damages within the limits of adaptation of human and natural systems, that assessing intentional climate interventions becomes compelling.
The request for this report is a product of this moment. The Committee was asked to consider both the potential and need for atmospheric methane removal. In both cases, the focus is not on deployment of a novel technology but on the research needed to build a knowledge base about the full sociotechnical problem. Study of atmospheric methane removal technologies is a nascent area of research. Therefore, the Committee has sought to assess the information available and identify research areas where further work could inform a more complete social and technical assessment of atmospheric methane removal technologies as a set of responses to address climate change.
Because this area of study is so new, the Committee deliberated over scope, terminology, and definitions. We lay out this thinking in the introductory chapters of this report. Also important for this Committee to grapple with was a fundamental question:
Why consider atmospheric methane removal? This question informed the entire report, and we devote a chapter to explore a broad set of possible answers—from extending the set of methane mitigation technologies to address diffuse and low-concentration methane emissions (such as those from natural methane sources, which have the potential to increase significantly in a warming world), with implications for a “methane emissions gap” between our climate goals and available methane mitigation measures, to the case for restoring the atmosphere to preindustrial methane concentration and recovery and use of low-concentration methane. It was more important at this early stage of knowledge discovery to consider the bounds of the question rather than form a single answer.
As the first major assessment of the potential and need for atmospheric methane removal, this report provides an opportunity to engage researchers in the academic, government, and private sectors to consider a research agenda to build the knowledge base and answer key questions around the feasibility and desirability of developing this technology. We are grateful to the enthusiastic engagement of the research community, particularly those who submitted input, participated in our workshops, and wrote commissioned papers. (See Appendix C for contributors of input to the study.) The Committee sought to utilize scholarship across many well-established fields while also seeking to understand ways that atmospheric methane removal is unique.
The experts who formed this study Committee represented a wide range of disciplinary expertise, from microbiology to social psychology and chemical engineering to atmospheric chemistry, demonstrating how many fields atmospheric methane removal touches. An important part of the Committee’s early work was taking time to share fundamental concepts from respective disciplines and beginning to speak a similar language. This Committee represents the kinds of interdisciplinary teams that we hope pursue research in this area; this collaboration requires thoughtful investments of time and resources. I am grateful to each Committee member for their dedication and contributions to the report. I am also deeply grateful to Rachel Silvern and Brent Heard for their insights, indefatigable support, flawless organization, adaptability, and humor over the past many months that made this report possible.
Gabrielle Dreyfus, Chair
Committee on Atmospheric Methane Removal: Development of a Research Agenda
