Climate change challenges coastal blue carbon restoration in China

Coastal blue carbon has become an emerging natural climate solution (NCS) that offers significant potential for mitigating global climate change while providing various ecosystem services. However, blue carbon ecosystems, including mangroves, tidal salt marshes, and seagrass meadows, are susceptible to the impacts of climate change, which in turn affects their potential to mitigate climate change. In this study, we employed the MaxEnt to evaluate the potential suitable areas and carbon sink potential of China's Coastal blue carbon ecosystem under three climate scenarios for the present and projected conditio ns in 2050. Our results reveal that China's coastal blue carbon ecosystems have an estimated carbon sequestration potential of 8.65 * 105 t/a. Specifically the potential annual carbon sequestration of mangroves is 1.457 * 105 t/a, tidal salt marshes is 6.714 * 105 t/a, and seagrass is 4.769 * 104 t/a. By 2050, due to climate change, the annual carbon sequestration potential of China's coastal blue carbon is projected to decrease by 0.733-2.351 * 105 t/a, representing an 8-27 % reduction from the current levels. Furthermore, the distribution of potential suitable areas for these blue carbon ecosystems is expected to shifted to different degrees, among which the potential suitable areas of mangrove will be transferred to the greatest extent, showing a trend of northward expansion. Future conservation and restoration efforts for blue carbon ecosystems ought to consider the impact of climate change and fully utilize the potential of blue carbon.