Expert views on the governance of marine sedimentary carbon for climate change mitigation

With growing interest in ocean-based climate solutions, attention is increasingly turning to the role of marine sedimentary carbon (SC) as a potential contributor to climate change mitigation. Substantial organic carbon stocks and burial processes operate across continental shelf sediments, yet the governance of this resource remains at an early and conceptually fragmented stage. This study examines the prospects for governing SC as a climate-mitigating natural resource through 20 semi-structured interviews with experts in blue carbon, marine governance, fisheries governance, economics, and policy. The findings reveal significant challenges relating to the definition and conceptual boundaries of the SC system; persistent scientific uncertainties in measuring stocks, flows, and anthropogenic impacts; and tensions concerning valuation, accounting, and the viability of economic instruments. These issues intersect with an already crowded institutional landscape and low public visibility of SC. Interviewees emphasised the need for pragmatic integration of SC considerations into existing governance frameworks rather than the creation of new institutions, supported by monitoring approaches capable of informing decisions under uncertainty. While economic instruments were viewed as limited in the near term, experts highlighted opportunities to align SC governance with broader marine management objectives, including biodiversity protection and transboundary cooperation. The study concludes that advancing SC governance will require improved empirical understanding of human impacts, clearer operational definitions, and enhanced public and stakeholder engagement to build legitimacy around potential interventions. These insights provide an initial foundation for designing governance frameworks for an emerging marine carbon resource with significant, yet uncertain, climate mitigation potential.