The Science, Engineering, and Validation of Marine Carbon Dioxide Removal and Storage.

Scenarios to stabilize global climate and meet international climate agreements require rapid reductions in human carbon dioxide (CO₂) emissions, often augmented by substantial carbon dioxide removal (CDR) from the atmosphere. While some ocean-based removal techniques show potential promise as part of a broader CDR and decarbonization portfolio, no marine approach is ready yet for deployment at scale because of gaps in both scientific and engineering knowledge. Marine CDR spans a wide range of biotic and abiotic methods, with both common and technique-specific limitations. Further targeted research is needed on CDR efficacy, permanence, and additionality as well as on robust validation methods-measurement, monitoring, reporting, and verification-that are essential to demonstrate the safe removal and long-term storage of CO₂. Engineering studies are needed on constraints including scalability, costs, resource inputs, energy demands, and technical readiness. Research on possible co-benefits, ocean acidification effects, environmental and social impacts, and governance is also required.