Most net zero policies and major scientific models rely on carbon dioxide removal (CDR) to limit global heating to 2℃. The most commonly known methods include afforestation, bioenergy with carbon capture, and direct air capture - but various proposals are emerging for ocean-based CDR technologies.

Could marine CDR offset emissions from sectors that cannot easily decarbonise, or are the costs and risks too great? Bertie sat down with oceanographer David Ho to discuss these questions, shortly after he returned from the 4th International Conference on Carbon Dioxide Removal in Milan.

David Ho is a professor at University of Hawaiʻi at Mānoa, and a lead author on the upcoming IPCC methodology report on carbon dioxide removal and carbon capture, utilisation and storage. His 2023 article for Nature criticising overreliance on CDR has been downloaded more than 100,000 times.

Further reading:

'Three challenges to marine carbon dioxide removal', npj Ocean Sustainability, November 2025
Principles for responsible and effective marine carbon dioxide removal development and governance, 2025
'Marine carbon dioxide removal may be a future climate solution', Dialogues on Climate Change, November 2024
'Can coastal and marine carbon dioxide removal help to close the emissions gap? Scientific, legal, economic, and governance considerations', Elementa: Science of the Anthropocene, August 2024
'Deployment expectations of multi-gigatonne scale carbon removal could have adverse impacts on Asia’s energy-water-land nexus', Nature Communications, July 2024
'Carbon dioxide removal is not a current climate solution — we need to change the narrative', Nature, April 2023

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