A scientific summary for policy-makers: the state of the science for Marine Carbon Dioxide Removal (mCDR)

Key messages

• Due to the insufficient rate of emission reductions, there is increasing interest in exploring the potential for carbon dioxide removal in marine environments.

• Marine carbon dioxide removal (mCDR) approaches are still in the early stages of development; many knowledge gaps and uncertainties remain.

• Each mCDR approach comes with trade-offs in terms of durability, energy demand and environmental impact, and would require large ocean areas if considered for large-scale implementation.

• A key challenge is to enhance technical and regulatory monitoring, reporting and verification (MRV) capacities for marine interventions.

• Future implementation of any and all mCDR approaches will require site-specific assessments, robust regulatory frameworks and an approach that balances ocean protection and use.