Destruction of coastal habitats may release as much as 1 billion tons of carbon into the atmosphere each year, 10 times higher than previously reported. The analysis provides the most comprehensive estimate of global carbon emissions from the loss of these coastal habitats to date: 0.15 to 1.2 billion tons. It suggests there is a high value associated with keeping these coastal-marine ecosystems intact as the release of their stored carbon costs roughly $6-$42 billion annually.
The carbon, when captured through biological processes and stored in the sediment below mangroves, sea grasses and salt marshes, is called “blue carbon.” When these wetlands are drained and destroyed, the sediment layers below begin to oxidize. Once this soil, which can be many feet deep, is exposed to air or ocean water it releases carbon dioxide over days or years.