A Research Strategy for
Committee on A Research Strategy for Ocean-based
Carbon Dioxide Removal and Sequestration
Ocean Studies Board
Division on Earth and Life Studies
A Consensus Study Report of
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This activity was supported by contracts between the National Academy of Sciences and ClimateWorks Foundation, Contract No. 10004979. 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: 978-0-309-08761-2
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Suggested citation: National Academies of Sciences, Engineering, and Medicine. 2022. A Research Strategy for Ocean-based Carbon Dioxide Removal and Sequestration. Washington, DC: The National Academies Press. https://doi.org/10.17226/26278.
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COMMITTEE ON A RESEARCH STRATEGY FOR OCEAN-BASED CARBON DIOXIDE REMOVAL AND SEQUESTRATION
Scott C. Doney, Chair, University of Virginia, Charlottesville
Holly Buck, University at Buffalo, NY
Ken Buesseler, Woods Hole Oceanographic Institution, Woods Hole, MA
M. Debora Iglesias-Rodriguez, University of California, Santa Barbara
Kathryn Moran, University of Victoria, BC
Andreas Oschlies, GEOMAR Helmholtz Centre for Ocean Research Kiel, Germany
Phil Renforth, Heriot-Watt University, Edinburgh, UK
Joe Roman, University of Vermont, Burlington
Gaurav N. Sant, University of California, Los Angeles
David A. Siegel, University of California, Santa Barbara
Romany Webb, Columbia Law School, New York, NY
Angelicque White, University of Hawai’i at Manoa, Honolulu
Kelly Oskvig, Senior Program Officer, Ocean Studies Board
Bridget McGovern, Research Associate, Ocean Studies Board
Trent Cummings, Senior Program Assistant, Ocean Studies Board, until July 2021
Elizabeth Costa, Program Assistant, Ocean Studies Board
OCEAN STUDIES BOARD
Larry A. Mayer (NAE), Outgoing Chair, University of New Hampshire, Durham
Claudia Benitez-Nelson, Incoming Chair, University of South Carolina, Columbia
Mark Abbott, Woods Hole Oceanographic Institution, Woods Hole, Massachusetts
Carol Arnosti, University of North Carolina, Chapel Hill
Lisa Campbell, Duke University, Durham, North Carolina
Thomas S. Chance, ASV Global, LLC (ret.), Broussard, Louisiana
Daniel Costa, University of California, Santa Cruz
John Delaney, University of Washington (ret.), Seattle
Scott Glenn, Rutgers University, New Brunswick, New Jersey
Patrick Heimbach, University of Texas, Austin
Marcia Isakson, University of Texas, Austin
Lekelia Jenkins, Arizona State University, Tempe
Nancy Knowlton (NAS), Smithsonian Institution (ret.), Washington, District of Columbia
Anthony MacDonald, Monmouth University, West Long Branch, New Jersey
Thomas Miller, University of Maryland, Solomons
S. Bradley Moran, University of Alaska, Fairbanks
Ruth M. Perry, Shell Exploration & Production Company, Houston, Texas
James Sanchirico, University of California, Davis
Mark J. Spalding, The Ocean Foundation, Washington, District of Columbia
Richard Spinrad, Oregon State University, Corvallis
Robert S. Winokur, Michigan Tech Research Institute, Silver Spring, Maryland
OSB Staff Members
Susan Roberts, Director
Stacee Karras, Senior Program Officer
Kelly Oskvig, Senior Program Officer
Emily Twigg, Senior Program Officer
Vanessa Constant, Associate Program Officer
Megan May, Associate Program Officer
Alexandra Skrivanek, Associate Program Officer
Bridget McGovern, Research Associate
Shelly-Ann Freeland, Financial Business Partner
Thanh Nguyen, Financial Business Partner
Trent Cummings, Senior Program Assistant, until July 2021
Kenza Sidi-Ali-Cherif, Program Assistant
Grace Callahan, Program Assistant
Elizabeth Costa, Program Assistant
Over the past several hundred years, society’s expanding consumption of fossil fuels and extensive alteration of the terrestrial biosphere has led to a dramatic rise in atmospheric levels of carbon dioxide (CO2) and other greenhouse gases. The resulting global climate change is one of the most pressing issues facing society today. Slowing human CO2 emissions is particularly challenging because fossil fuel use is embedded widely in our modern energy system and economy. Thus, a broad net is being cast searching for a portfolio of solutions to decarbonize the economy and perhaps even actively remove and safely sequester CO2 away from the atmosphere.
More than a half century ago, Revelle and Suess1 wrote a pioneering study on the ocean’s role in removing from the atmosphere excess CO2 due to human emissions. Their paper was published at a time when there was quite limited scientific information on the ocean carbon system. It was published just months before the start of the iconic atmosphere CO2 time series by David Keeling in 1957 at Mauna Loa, Hawai’i, that provides one of the most robust constraints on the fate of human CO2 emissions. Based on decades of subsequent ocean science and carbon cycle research, modern estimates clearly indicate that natural ocean processes act to remove from the atmosphere about a quarter of human CO2 emissions from fossil fuel consumption and deforestation. Thus, the ocean already provides an invaluable service slowing the atmospheric growth of CO2 and associated climate change, though at the cost of rising levels of ocean acidification.
The predominant long-term fate of excess CO2 from human emissions is to end up in the ocean over centuries to millennia. This raises the question of whether society could (and should) attempt to accelerate ocean processes that remove and store CO2 away from the atmosphere. Numerous approaches for deliberate ocean carbon dioxide removal (CDR), ranging across biological and geochemical methods to more industrial techniques, have been proposed by scientists, engineers, and technologists. As described in the body of this report, there remain crucial unresolved questions regarding many aspects of ocean CDR, and this report provides an overview of our current state of understanding and a possible research path forward to resolve these major knowledge gaps.
1 Revelle, R., and H.E. Suess, 1957: Carbon dioxide exchange between atmosphere and ocean and the question of an increase of atmospheric CO2 during the past decades, Tellus, 9(1), 18-27, https://doi.org/10.1111/j.2153-3490.1957.tb01849.x.
This is a report on a research agenda to better inform future societal decisions on ocean CDR; the Committee is not advocating either for or against possible future ocean CDR deployments, and the Committee recognizes that ocean CDR would, at best, complement the role of climate mitigation approaches including decarbonization.
This report builds heavily on previous National Academies of Sciences, Engineering, and Medicine studies, in particular the rationale and framing for research on CDR provided in the 2015 report on Climate Intervention: Carbon Dioxide Removal and Reliable Sequestration. The ocean CDR report here also adds to the more terrestrial focus of the 2019 report on Negative Emissions Technologies and Reliable Sequestration: A Research Agenda.
The report benefited greatly from many insightful presentations given by external speakers and the participants at the Committee’s public meetings and workshop. Because of COVID-19, the Committee’s work was completed under the unusual conditions of virtual-only meetings, a challenge compounded by a relatively short time span for the report. I want to extend a special thanks to the Committee members and National Academies staff for their dedication, energy, and thoughtful discussion and contributions over the past year.
Chair, Committee on A Research Strategy for Ocean Carbon Dioxide Removal and Sequestration
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:
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 Mark Barteau, Texas
A&M University, and Jim Yoder, 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.
During the study process, we had a number of speakers both at committee meetings and at a series of workshops. We thank the following individuals for their contributions during the study process: Brad Ack, Jess Adkins, Mark Preston Aragones, Trisha B. Atwood, David Babson, Lennart Bach, Philip Boyd, Ellen Briggs, Wil Burns, Ken Caldeira, Fei Chai, Francisco Chavez, Bill Collins, Sarah Cooley, Emily Cox, Andrew Dickson, Carlos M. Duarte, Matthew Eisaman, Julio Friedmann, Halley E. Froehlich, Oliver Geden, Dwight Gledhill, Olavur Gregersen, Nicolas Gruber, Jill Hamilton, Barbara Haya, Stephanie Henson, Joseph Hezir, Baerbel Hoenisch, K. John Holmes, Anna-Maria Hubert, Xabier Irigoien, Nick Kamenos, David P. Keller, David Koweek, Dorte Krause-Jensen, Tim Kruger, Ricardo Letelier, Catherine Lovelock, Niall MacDowell, Filip Meysman, Juan Moreno-Cruz, David P. Morrow, Ryan Orbuch, Andy Pershing, Albert J. Plueddemann, Greg Rau, Miles Richardson, Ros Rickaby, Kate Ricke, Andy Ridgwell, Ulf Riebesell, Joellen Russell, Christopher L. Sabine, Terre Satterfield, Raymond Schmitt, Gyami Shrestha, Lisa Suatoni, Shuchi Talati, Chris Vivian, Brian von Herzen, Marc von Keitz, George Waldbusser, Heather Willauer, Phillip Williamson, Richard Zeebe, and Robert Zeller.
1.1 Human Perturbations to the Global Carbon Cycle
1.2 Climate Mitigation, Decarbonization, and Carbon Dioxide Removal
1.3 Seawater CO2 and Carbonate System Chemistry
1.4 Ocean Carbon Cycle and Ocean Anthropogenic CO2 Uptake
1.5 Ocean-Based Carbon Dioxide Removal
1.6 Origin and Purpose of the Study
1.7 Study Approach and Framework for Assessment
2 CROSSCUTTING CONSIDERATIONS ON OCEAN-BASED CDR R&D
2.1 Legal and Regulatory Landscape
2.2 Social Dimensions and Justice Considerations
2.3 Other Crosscutting Considerations
3.6 Summary of Carbon Dioxide Removal Potential
4 ARTIFICIAL UPWELLING AND DOWNWELLING
4.6 Summary of Carbon Dioxide Removal Potential
5.5 Summary of Carbon Dioxide Removal Potential
6 RECOVERY OF MARINE ECOSYSTEMS
6.6 Summary of Carbon Dioxide Removal Potential
7 OCEAN ALKALINITY ENHANCEMENT
7.5 Environmental and Social Impacts
7.6 Monitoring and Verification
7.8 Summary of Carbon Dioxide Removal Potential
8 ELECTROCHEMICAL ENGINEERING APPROACHES
8.6 Summary of Carbon Dioxide Removal Potential
9 SYNTHESIS AND RESEARCH STRATEGY
9.1 A General Framework for Ocean-Based Carbon Dioxide Removal Strategies
9.2 Common Components of Any Research Implementation
9.3 Summary of Assessed Ocean-based Carbon Dioxide Removal Strategies
B WORKSHOP AND MEETING PUBLIC PRESENTATIONS TO THE COMMITTEE
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