'Global rules and standards': how the International Law of the Sea Regime shapes sub-seabed CO₂ storage policies to fight climate change

The proliferation of sub-seabed carbon dioxide (CO₂) storage technologies to mitigate hard-to-abate CO₂ emissions and combat climate change may affect environmental obligations under the United Nations Convention on the Law of the Sea (LOSC) and related treaties. While CO₂ emissions pollute the marine environment and must be reduced, sub-seabed storage, considered a form of ‘dumping’, can also pose environmental risks. The LOSC requires adherence to ‘global rules and standards’ for the prevention of marine pollution by dumping, often understood to include the 1972 London Convention and its 1996 Protocol. Nevertheless, the limited global deployment of sub-seabed CO₂ storage means there may be insufficient practice to demonstrate which rules and standards have been ‘globally’ accepted. This article explores the environmental regulation of sub-seabed CO₂ storage under the LOSC, focusing on the application of the ‘global rules and standards’ requirement, the due diligence obligation, environmental impact assessment, and the precautionary approach.