Coastal ecosystems are being asked to solve a governance problem they did not create. Mangrove forests, seagrass meadows and tidal salt marshes store carbon at rates unmatched by most terrestrial systems, yet the policy architecture meant to protect them remains fragmented across levels and sectors. A new narrative review of 24 studies published between 2019 and 2026 makes the diagnosis plain: integration fails institutionally before it fails technically. That distinction matters because it shifts the conversation from what we can measure to what we are willing to coordinate.
The review identifies recurring bottlenecks, unclear carbon rights, incompatible accounting rules, the non-recognition of sink preservation as a mitigation strategy, that stall initiatives between announcement and implementation. Local pilots generate credits, but those credits rarely scale into national markets. Bottom-up feedback lacks upward channels. What emerges is a pattern of expert-dominated knowledge interfaces, external and post-colonial dominance, and elite capture that skews who designs projects and who benefits from them. This is not simply a technical gap in carbon accounting; it is a structural failure of governance design. Our own work on Salt Marsh Vegetation Boosts Organic Carbon Storage in Yellow Sea Wetlands reinforces the point: we can validate the biogeochemical mechanisms of carbon storage, but that empirical confidence means little if the institutional rules for crediting those stocks remain absent or incompatible. Similarly, the Validating transboundary risk: a fuzzy framework for blue carbon policy shocks demonstrates that policy shocks themselves can propagate across borders, meaning fragmented governance does not just fail locally, it creates systemic risk.
The review closes a descriptive-explanatory gap by mapping six recurring bottleneck, determinant, pathway chains. The most actionable finding is that effective responses align authoritative multilevel rules, equitable polycentric participation and adaptive public knowledge infrastructure. No single statute, market mechanism or financing instrument can do the work alone. That is a sobering conclusion for policymakers who prefer simple levers, but it is also an honest one. The review also notes that politicisation, corruption and the upward feedback channel remain without documented responses. Those are not minor gaps; they are the hardest problems in environmental governance. The open-access observatory model we have documented in A validated open-access observatory for Africa's multi-ecosystem ocean intelligence offers one template for building the adaptive knowledge infrastructure the review calls for, but infrastructure alone cannot resolve power asymmetries. The specific question to watch is whether the post-2026 policy cycle can produce binding rules for carbon rights in coastal sediments before the next wave of voluntary carbon markets locks in inequitable ownership patterns.