Marine Carbon Dioxide Removal: Potential Ways to Harness the Ocean to Mitigate Climate Change

By Scott Doney, Assistant Director for Ocean Climate Science and Policy and Jane Lubchenco, Deputy Director for Climate and Environment

Confronting the climate crisis requires a rapid reduction in carbon dioxide (CO₂) and other greenhouse gas emissions at home and abroad. President Biden has set an ambitious U.S. goal to achieve a net-zero emissions economy by no later than 2050, and his Investing in America agenda advances historic climate actions by accelerating the deployment of clean energy, electric vehicles, and public transportation. As these technologies are further refined and scaled for use now, the Biden-Harris Administration is also committed to exploring emerging, next-generation climate technologies.

Carbon dioxide removal (CDR) is one of those potentially powerful new tools, but one for which we need more information before proceeding at scale. CDR focuses on removing CO₂ that is already in the atmosphere or in the upper ocean, and permanently storing it for centuries or longer. Marine CDR is less well known than terrestrial CDR, but a variety of ways to capture and store CO2 from the ocean have been suggested.  For example, marine CDR may include altering the chemical composition of sea water so that the ocean absorbs more CO₂ from the atmosphere; using electrochemical techniques to remove dissolved CO₂ from seawater and then storing that CO₂ underground; or adding nutrients such as iron to areas of the ocean to encourage the growth of microscopic plankton that can sink to the seafloor and be stored for centuries or longer. Each of these different approaches has its own potential benefits and problems; moreover, the efficacy of each may vary from one part of the ocean to another. These negative-emission approaches have the potential to counterbalance emissions from hard-to-abate sectors as well as remove legacy greenhouse gas emissions, both of which would complement the rapid greenhouse gas emissions reduction we will see as we transition to a clean energy future.

Obtaining new knowledge about the safest and most effective approaches to marine CDR is a high priority.  Therefore, the White House Office of Science and Technology Policy (OSTP) is announcing a new Fast-Track Action Committee on Marine Carbon Dioxide Removal. Under the authority of OSTP’s National Science and Technology Council, the Committee will evaluate the merits of and concerns about different types of marine CDR and shape relevant policy and research on safe and effective marine CO₂ removal and carbon sequestration. The committee includes experts from more than a dozen federal departments and agencies and it fulfills one of the recommendations of the U.S. Ocean Climate Action Plan (OCAP) released earlier this year.  The OCAP highlights the key role of the ocean in meeting the climate challenge.  Among other actions, the OCAP called for a substantial ramp up in federal research and development on marine CDR to guide development and deployment decisions, and to protect human health, the marine environment, and potentially affected communities.

Over the next year, the interagency Committee will develop an implementation plan to advance marine CDR and establish sufficient knowledge that can potentially guide CDR deployment decisions as part of America’s net-zero emissions future. The Committee will:

• Draft recommendations for policy, permitting, and regulatory standards for marine CDR research and implementation;
• Develop a plan for a comprehensive federal research and scaled testing program for promising marine CDR approaches to identify marine CDR benefits, risks, and challenges;
• Explore approaches for coordinating public-private funded marine CDR research activities.

The Committee efforts build on and will help unify an already growing federal investment in marine CDR research as part of the Biden-Harris Administration’s Investing in America agenda. Earlier this month, the National Oceanic and Atmospheric Administration (NOAA) and National Oceanographic Partnership Program (NOPP) announced marine CDR research awards totaling $24 million. Across 17 project selections, the NOPP/NOAA funding will support the assessment of risks, co-benefits, and science needs to build regulatory frameworks for testing and scaling CDR from ocean alkalinity enhancement, macroalgal cultivation, enhanced weathering, and electrochemical approaches. In further support of these efforts, the Department of Energy (DOE) is developing a complementary research program that will research ways to measure and track marine CO₂ removal more transparently. DOE also released a Notice of Intent for Small Marine Carbon Dioxide Removal (CDR) Pilots, which will move beyond fundamental research to demonstrate the feasibility and cost of scaling up marine CDR approaches from lab-scale trials to larger demonstration projects. In short, the urgency of the climate crisis and the Biden-Harris Administration’s focus on scientifically sound climate solutions make obtaining answers about marine CDR a high priority.  We look forward to their findings and recommendations.   

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