Coastal ecosystems are critical to maintaining human well-being and global biodiversity. In particular, mangroves, tidal salt marshes, and seagrasses provide numerous benefits and services that contribute to people’s ability to mitigate and adapt to the impacts of climate change. Many of these services are essential for climate adaptation and resilience along coasts, including protection from storm surge and sea level rise, erosion prevention along shorelines, coastal water quality regulation, nutrient recycling, sediment trapping, habitat provision for numerous commercially important and endangered marine species, and food security for many coastal communities around the world.
Despite their benefits and services, coastal blue carbon ecosystems are some of the most threatened ecosystems on earth, with an estimated 340,000 to 980,000 hectares being destroyed each year. Although their historical extent is difficult to determine due to dramatic losses which occurred before accurate mapping was possible, it is estimated that up to 67% of the historical global mangrove range, 35% of tidal salt marshes, and 29% of seagrasses have been lost. If these trends continue at current rates, a further 30–40% of tidal marshes and seagrasses and nearly all unprotected mangroves could be lost in the next 100 years.
Increasingly, coastal ecosystems are being recognized for their important role in carbon sequestration and, when degraded, their potential to become sources of carbon emissions. Progress has been made to include these systems in international and national policy and finance mechanisms, but full integration of coastal management activities as part of countries’ portfolio of solutions to mitigate climate change has not yet been realized.
