Carbon removal using coastal blue carbon ecosystems is uncertain and unreliable, with questionable climatic cost-effectiveness

The authors assess the feasibility of achieving quantified and secure carbon removal (negative emissions) through the restoration of coastal blue carbon ecosystems (mangrove forests, seagrass meadows and tidal saltmarshes). Seven issues that affect the reliability of carbon accounting for this approach are considered. Information on restoration costs is also reviewed, with the conclusion that costs are highly uncertain, with lower-range estimates unrealistic for wider application. Carbon Dioxide (CO₂) removal using coastal blue carbon restoration therefore has questionable cost-effectiveness when considered only as a climate mitigation action. Their restoration is nevertheless highly advantageous for climate adaptation, coastal protection, food provision and biodiversity conservation. Such action can therefore be societally justified in very many circumstances, based on the multiple benefits that such habitats provide at the local scale.

Reference: Williamson, P. & Gattuso, J. (2022). Carbon removal using coastal blue carbon ecosystems is uncertain and unreliable, with questionable climatic cost-effectiveness. Front. Clim., 4, 853666. http://doi.org/10.3389/fclim.2022.853666