Toward Responsible and Informed Ocean-Based Carbon Dioxide Removal Research and Governance Priorities

The report evaluates seven ocean-based carbon dioxide removal (CDR) strategies: coastal blue carbon restoration, seaweed cultivation, ocean fertilization, artificial upwelling, alkalinity enhancement, electrochemical techniques, and artificial downwelling. It finds that most of these methods are in early development with significant scientific gaps and environmental risks. The authors argue that current international legal frameworks, such as UNCLOS and the CBD, are insufficient to proactively regulate these technologies. To address this, the report recommends increasing funding for collaborative research, establishing an international code of conduct for at-sea trials, and developing a comprehensive global governance regime to manage transboundary impacts and ensure equitable benefit sharing.

• Coastal blue carbon restoration is the most established approach, with a potential to increase carbon removal by 0.20.33 GtCO2/yr by 2050, though estimates vary up to 0.8 GtCO2/yr.
• Seaweed cultivation could sequester between 0.1 and 1.0 GtCO2/yr, but its efficacy is limited by air-sea gas exchange and the permanence of carbon when sunk to the deep ocean.
• Ocean fertilization, particularly with iron, has a high theoretical potential (0.11.0 GtCO2/yr), but experiments have not verified the necessary transfer of organic matter to the deep ocean or corresponding atmospheric carbon uptake.
• Alkalinity enhancement (OAE) can remove 0.1 to 1.0 GtCO2/yr and may provide the co-benefit of reducing local ocean acidification, though it risks introducing toxic trace metals into ecosystems.
• Electrochemical techniques for CDR are capital and energy intensive, with estimated costs ranging from $150 to $2,500/tCO2, and they produce toxic byproducts like chlorine gas.
• Artificial upwelling and downwelling are considered less viable for large-scale CDR due to high costs and the risk of 'outgassing' CO2 from deep waters back into the atmosphere.
• Existing international legal frameworks, including UNCLOS, the CBD, and the London Convention/Protocol, are fragmented and were not designed for CDR, creating regulatory uncertainty.
• The 'no-harm' rule under customary international law requires countries to prevent activities within their jurisdiction from causing significant transboundary harm to other states or the high seas.
• Measurement, Reporting, and Verification (MRV) for ocean CDR is significantly more challenging than for land-based CDR due to the ocean's scale and constant movement, making carbon accounting costly and complex.
• Large-scale ocean CDR deployment may require extensive land-based infrastructure for mining and transport, meaning governance must extend beyond maritime boundaries to include onshore impacts.

APA

Lebling, K., Northrop, E., McCormick, C., & Bridgwater, E. (2022). Toward Responsible and Informed Ocean-Based Carbon Dioxide Removal Research and Governance Priorities. World Resources Institute. https://files.wri.org/d8/s3fs-public/2022-11/towards-responsible-and-informed-ocean-based-carbon-dioxide-removal.pdf?VersionId=xBQNBFfClUR._8Ovi7Um9dyziC9r61HW

Chicago

Lebling, Katie, Eliza Northrop, Colin McCormick, and Elizabeth Bridgwater. Toward Responsible and Informed Ocean-Based Carbon Dioxide Removal Research and Governance Priorities. World Resources Institute, 2022. https://files.wri.org/d8/s3fs-public/2022-11/towards-responsible-and-informed-ocean-based-carbon-dioxide-removal.pdf?VersionId=xBQNBFfClUR._8Ovi7Um9dyziC9r61HW.

Wikipedia

{{cite report |last1=Lebling |first1=Katie |last2=Northrop |first2=Eliza |last3=McCormick |first3=Colin |last4=Bridgwater |first4=Elizabeth |title=Toward Responsible and Informed Ocean-Based Carbon Dioxide Removal Research and Governance Priorities |publisher=World Resources Institute |date=November 2022 |url=https://files.wri.org/d8/s3fs-public/2022-11/towards-responsible-and-informed-ocean-based-carbon-dioxide-removal.pdf?VersionId=xBQNBFfClUR._8Ovi7Um9dyziC9r61HW |access-date=23 October 2026 |via=Climate Insights Directory}}

BibTeX

@techreport{lebling2022toward, author = {Lebling, Katie and Northrop, Eliza and McCormick, Colin and Bridgwater, Elizabeth}, title = {{Toward Responsible and Informed Ocean-Based Carbon Dioxide Removal Research and Governance Priorities}}, institution = {World Resources Institute}, year = {2022}, month = nov, url = {https://files.wri.org/d8/s3fs-public/2022-11/towards-responsible-and-informed-ocean-based-carbon-dioxide-removal.pdf?VersionId=xBQNBFfClUR._8Ovi7Um9dyziC9r61HW}, urldate = {2026-10-23}, note = {Indexed by Climate Insights Directory} }