Blue Carbon in an Era of Carbon Accounting

[Geoengineering News]

https://www.annualreviews.org/content/journals/10.1146/annurev-environ-121522-043142

Authors: M. Ward, M.T. Costa, A.M. Ricart, S. Crooks, L.M. Wedding and P.I. Macreadie

 

13 July 2026

Abstract

Blue carbon ecosystems—mangroves, tidal marshes, seagrass meadows, and, increasingly, seaweeds—are being rapidly integrated into climate mitigation frameworks. Yet, despite their prominence in global carbon offset discourse, blue carbon projects remain dominated by mangroves (∼89% of projects). Here, we synthesize recent developments in blue carbon science, carbon accounting, and market integrity. Global restoration potential could deliver annual removals of ∼109 (98–119; 95% CI) million tonnes of organic carbon, while habitat loss causes annual emissions of up to ∼63 (55–71) million tonnes. Realizing carbon benefits is constrained by monitoring, reporting, and verification costs, data gaps, and methodological challenges. We identify four priority areas for advancing blue carbon crediting: (a) spatial mapping, particularly for seagrasses and seaweeds; (b) lateral and vertical carbon transport modeling, (c) emissions factor development, and (d) incorporation of novel carbon pathways (e.g., alkalinity export). As blue carbon definitions expand and demand for implementation accelerates, ensuring scientific rigor and project integrity is critical to scaling restoration that delivers durable climate and biodiversity gains.

Source: Annual Review Of Environment and Resources