Abstract
Climate change threatens seagrass ecosystems, which are vital for blue carbon sequestration and associated co-benefits. Our study on Hainan Island in the South China Sea assessed climate impacts on seagrass habitats using ensemble modeling under two scenarios (RCP4.5 and RCP8.5) for 2050 and 2100. We found the current seagrass carbon stock is approximately 1.194 Tg, but projections show habitat suitability could decrease by up to 74.78% by 2100 under the severe scenario, potentially causing economic losses of $1.02-1.27 billion. While seagrass restoration requires initial investment, it offers substantial long-term climate benefits. Our analysis indicates seagrasses may migrate toward higher latitudes due to climate change, though new habitats could emerge along Hainan's southern coast by 2100. These findings emphasize the urgency of conservation and restoration efforts to safeguard seagrass ecosystems and their vital role in climate change mitigation strategies.