Variable Impacts of Climate Change on Blue Carbon

Blue carbon provides opportunities to mitigate climate change while increasing ecosystem services for coastal communities, including climate change adaptation; however, blue carbon ecosystems are vulnerable to climate change, leading to uncertainties in the future efficacy of these ecosystems. In this review, we assess the potential impacts of climate change on blue carbon. Despite uncertainties, carbon sequestration in coastal ecosystems is enhanced by landward migration of blue carbon habitats, maintenance of sediment supply, restoration, and improved water quality. As an example, landward migration of mangroves could result in carbon sequestration of 1.5 Pg by 2100. Mudflats, seaweed beds, and coastal swamp forests could also contribute to climate change mitigation, although there are large data gaps. Achieving the full potential of blue carbon requires protection and restoration of ecosystems and facilitation of changes in ecosystem distributions with climate change, actions that will also deliver adaptation benefits. Conversely, in the worst-case coastal squeeze scenario, losses of 3.4 Pg of sequestered carbon by 2100 could occur.