Panelists call for scrutiny of marine carbon dioxide removal and clearer governance

At a session hosted by the International Science Council at the UN Ocean Conference in Nice, panelists described marine carbon dioxide removal (MCDR) techniques as poorly understood and urged caution before large-scale deployment. "If I say the word marine carbon dioxide removal, I think many people wouldn't know what that is," said Dr. Peter Oan, policy director at the Institute of Marine Research in Norway.

Dr. Oan reviewed approaches sometimes discussed under MCDR — ranging from ocean alkalinity enhancement (chemically increasing seawater capacity to absorb CO2) to growing and burying kelp — and stressed the potential for unintended consequences. "If you try to modify the ocean carbon ecosystem...that means you actually change which fish eat, which animals, which organisms," he said, warning that changes can propagate through depths and food webs.

Panelists agreed that restoring coastal 'blue carbon' habitats such as mangroves, seagrass and salt marshes is broadly beneficial and likely to be supported, but they cautioned it will not scale to solve global CO2 problems alone. The session also highlighted social and cultural dimensions: speakers said benefit-sharing must recognize nonmonetary values — identity, heritage and spiritual ties to the sea — when interventions affect coastal communities.

Both experts argued that governance is fragmented across instruments and sectors and that better coordination is essential before proposing large-scale MCDR deployment. Dr. Peter said the new implementing agreement on marine biodiversity in areas beyond national jurisdiction could help — if it incorporates robust science and cross-sectoral rules — and he urged multilateral adherence to principles that prevent transferring harm across jurisdictions.

No policy commitments or votes were recorded at the session; panelists presented scientific concerns and urged policymakers at national and international levels to prioritize research, transparent governance and community engagement before pursuing large-scale MCDR.