Marine carbon dioxide removal

Reliable monitoring, reporting and verification (MRV) of marine carbon dioxide removal (mCDR) approaches will require accurate quantification of the amount of CO2 removed from the atmosphere, the durability of that removal, and non-carbon impacts on the marine environment. Given the vastness of the Ocean, the slow gas exchange across the sea surface, and the difficulty of defining baselines under ongoing environmental change, accurate estimates are challenging and need to include reliable uncertainty estimates. However, the required measurements, their integration with numerical models and the transparent provision of useful information are critical.

Background

Carbon Dioxide Removal (CDR) is defined as capturing CO2 from the atmosphere and storing it long-term, i.e. for decades to millennia. This storage can be on land, in the Ocean, in geological formations or in products. It can thus take many forms, from land and Ocean management practices such as forest or Blue Carbon ecosystem management and restoration, to technologies such as direct air capture, where chemical or physical processes are used to extract the CO2 directly from the air. To date, most CDR developments have been focused on land-based solutions. However, to achieve the required climate targets, novel CDR methods are required, including those linked to the Ocean.

Acknowledging the large oceanic carbon storage potential, marine CDR is currently being explored by publicly funded research and private start-ups. However, for marine CDR to be deployed responsibly more research is needed, and high-quality standards in terms of Monitoring, Reporting, and Verification (MRV) will be required. MRV is also crucial for ensuring that CDR activities generate the promised climate benefits and for the transparent regulation of a growing carbon removal market. Being able to accurately monitor, report, and verify the amount of carbon durably removed over time, and to measure the environmental effects of the marine CDR technology, is essential to evaluate the efficacy and effects of technologies being tested in controlled field trials and to assess if they are viable for future deployment at scale.

This working group provides input to the UN Decade of Ocean Science for Sustainable Development (2021-2030) societal outcome that aims for unlocking ocean-based solutions to climate change.

Working group objectives

The EMB Working Group on marine Carbon Dioxide Removal will aim be to focus on monitoring, reporting and verification (MRV) of these activities. The Future Science Brief should provide a state-of-the-art overview on the topic and conclude with relevant recommendations for policy and research funding. The document will be primarily written from a European perspective, but due to the global nature of marine CDR, it will have global relevance.

Specific topics that could be addressed in this document include (but are not limited to):

  • Explaining the role of the Ocean in naturally absorbing and storing atmospheric CO2 and how this will change with different climate change scenarios;
  • Outlining the amount of CDR needed to achieve climate objectives, current methods that are used or being developed, and the role that marine CDR can play;
  • Providing an overview of the different methodologies for increasing marine CDR (through human intervention), including their potential for success, limitations and risks. This should include the degree of CO2 sequestration from the atmosphere that could be reached by the different methods, timescales to achieve long-term storage, environmental and social concerns and risks, and potential benefits of the different methods;
    • Determining principles and research needs for reliable MRV, for deploying marine CDR methods at scale, and explaining the currently available methods, limitations, uncertainties and knowledge gaps for MRV of marine CDR, including the current and future potential to answer questions such as:
    • Does the marine CDR activity generate a measurable reduction in the atmospheric CO2 concentration?
    • To what extent can net additional Ocean uptake of atmospheric CO2 be tracked in response to the marine CDR activity using a combination of sensors, platforms, and models?
    • How will the durability (permanence) of stored carbon be monitored?
    • What are the impacts on marine ecosystems of marine CDR activities and how do they compare with the impacts of the no-action alternative or of other feasible climate mitigation measures?
    • What are the range of impacts to human populations and how do they compare with the impacts of no-action or of other feasible mitigation measures?

 

The Terms of Reference of the EMB Working Group is available here.

 

Output

The final output of the Working Group will be an EMB Future Science Brief to be published in early 2026.

 

Working Group Members

Chair: Prof. Helene Muri, Norwegian University of Science and Technology (NTNU), Norway

Co-Chair: Olivier Sulpis, CEREGE - Aix-Marseille University, CNRS, IRD, France

 

Contact at European Marine Board Secretariat: Ángel Muñiz Piniella Email

Image credit: Poseidon System, HCMR