Making blue carbon governable in China: standardisation, local experimentation and policy implications

China’s dual-carbon agenda has elevated blue carbon from a broad ecological aspiration to an actionable policy domain requiring accounting standards, measurement, reporting and verification (MRV), and institutional implementation pathways. This article examines how blue carbon policies are made operational in China, focusing on the institutional and technical devices through which marine carbon sinks are rendered calculable, verifiable and governable. Drawing on Jasanoff’s notion of sociotechnical imaginaries, it treats blue carbon not as a pre-given natural–technical object, but as a policy object iteratively defined, quantified, verified and recalibrated through policy narratives, standardisation, methodological rule-making and local experimentation. Methodologically, the study combines thematic analysis of national and coastal local policy documents, standards, accounting guidelines and regional methodologies with semi-structured interviews with 12 domain experts across policy, research and market-facing practice. Four findings emerge. First, blue carbon is constructed as a governable climate space, with standardisation functioning as metrological infrastructure. Second, implementation follows a two-wheel structure in which national policy direction and unified accounting grammars are made operable through local devices such as platforms, carbon-inclusion schemes, funds, insurance and judicial compensation. Third, market-facing implementation depends less on willingness to trade than on whether methodologies and MRV systems can institutionalise uncertainty into verifiable rules at bearable cost. Fourth, structural bottlenecks—cross-department coordination, uneven local capacity and unresolved risk allocation—shape credibility and scalability. The article contributes a mechanism-oriented account of how blue carbon moves from policy ambition to institutional operation under uncertainty.