Marine carbon dioxide removal advances but still faces big questions on measurement, scale, and governance

A new National Academies report finds that marine carbon dioxide removal (CDR) has moved forward with more research, technology development, and field testing, but major uncertainties remain. The 2026 update covers recent advances, updated assessment frameworks, and expanded sections on governance and ocean alkalinity enhancement. It stresses that marine CDR could supplement emissions cuts only if it becomes feasible at meaningful scale, which depends on solving measurement and verification problems, understanding long-term ecosystem effects, and building regulations that keep pace with the science. The report builds on the National Academies' 2022 work and includes a new State of Marine CDR module. It points out that viability is not just a technical question. Public acceptance, political decisions, and local environmental and social conditions will shape whether these approaches develop. Woods Hole Oceanographic Institution scientist Adam Subhas, who contributed to the report, led the first EPA-permitted ocean alkalinity enhancement field trial in the Gulf of Maine in August 2025. That trial is part of the LOC-NESS project and offers one example of the kind of field research needed to test assumptions. For anyone tracking carbon removal policy or investment, the report is a useful checkpoint. It shows progress in moving marine CDR from theory toward real-world experiments, while making clear that verification and governance are still the weak spots. Periodic updates are planned, so this document will likely become a reference point as the field develops.