Ambiguity in ocean governance: The advisory opinion of the International Tribunal for the Law of the Sea on climate change

In January 2027, the first Conference of the Parties to the new United Nations High Seas Treaty will take place. The meeting is expected to address key conflicts between marine conservation and ocean use in the context of climate change. The 2024 advisory opinion of the International Tribunal for the Law of the Sea (ITLOS) on climate change is therefore once again attracting attention. Many observers had expected the opinion to clarify the relationship between ocean protection and utilisation in climate policy. Such clarification is particularly important in relation to emerging marine carbon dioxide removal (mCDR) technologies, which seek to enhance oceanic carbon drawdown in order to mitigate climate change. ITLOS confirmed that states are obliged to protect the ocean from pollution caused by atmospheric CO2. However, it left open the question of whether mCDR should be regarded as marine pollution or as a contribution to marine environmental protection. This ambiguity could be mobilised politically to either promote or restrict mCDR. International organisations, EU institutions, and national authorities should therefore prepare for competing interpretations of the advisory opinion that may shape future climate and ocean governance.