SummaryMangroves, salt marshes, and sea grass meadows store considerable amounts of carbon in their biomass and soil, but when disturbed by land-use changes and development, much or all of the "blue carbon" is released into the atmosphere. Protecting those rapidly disappearing areas may prevent the release of 42 billion tons of stored carbon dioxide emissions into the air, according to a new RFF report.
In Blue Carbon: Global Options for Reducing Emissions from the Degradation and Development of Coastal Ecosystems, RFF and University of California, Davis coauthors Juha Siikamäki, James Sanchirico, Sunny Jardine, David McLaughlin, and Daniel Morris develop unique, high-resolution spatial estimates to explain where blue carbon habitats occur, how much carbon they store, the size of the emissions they currently experience, and their economic potential for mitigating greenhouse gas emissions.
The report estimates that mangroves are the chief blue carbon resource globally, providing over half of the total carbon storage in the habitats assessed. While blue carbon ecosystems, especially mangroves, store several times the amount of carbon per unit area than do tropical forests, their considerably smaller geographic extent makes the global carbon pool noticeably smaller than that of global forests. The report indicates that in most areas, CO2 emissions from mangrove forests could be avoided at less than $10 per ton of CO2. This suggests mangrove preservation may be a potentially competitive option for reducing global greenhouse gas emissions.
The feasibility of blue carbon conservation investments based on the stability and effectiveness of governing institutions could limit the potential size of the market for blue carbon offsets. Such limits can hamper the implementation of conservation efforts and increase their costs. Still, the wide range of benefits from the protection of blue carbon areas—including biodiversity protection and benefits to fisheries and local communities—could help make it a worthwhile investment.
Finally, the report finds that the similarities between protecting tropical forests and blue carbon habitats suggest that including blue carbon in Reducing Emissions from Deforestation and Forest Degradation (REDD) programs may be a viable path forward.
This report expands on an accompanying study that appeared in the Proceedings of the National Academy of Sciences titled Global Economic Potential for Reducing Carbon Dioxide Emissions from Mangrove Loss.