To achieve carbon neutrality, protecting and restoring blue carbon ecosystems is a key natural climate solution. However, these ecosystems have suffered extensive loss and degradation from human activities. A clear understanding of their trends and carbon potential is essential for effective neutrality strategies, yet their contributions remain insufficiently quantified and systematically assessed. This study establishes a database of Chinese blue carbon research literature and develops a framework to estimate blue carbon's contribution to carbon neutrality. Based on an assessment of blue carbon ecosystem trends in China from 2010 to 2020, we estimate its potential contribution to achieving national carbon neutrality under various restoration scenarios. The results show that: a) From 2010 to 2020, the area of China’s blue carbon vegetative ecosystems (i.e., arboreal and grassy mudflats) expanded, with annual growth rates of 1.15% for arboreal mudflats and 0.96% for grassy mudflats. However, tidal wetlands experienced a net loss of 28,000 hectares, primarily due to land reclamation. b) In 2010 and 2020, China’s coastal blue carbon storage was 772.12 and 773.50 million tC, respectively, with an overall increase of 1.38 million tC, mainly attributed to mangrove and salt marsh ecosystems. c) The annual blue carbon sequestration rate in 2020 averaged 12.13 million tC, up by 0.439 million tC compared to 2010, with salt marshes showing the highest carbon sequestration efficiency, accounting for 84.02% of vegetative habitat sequestration. d) Under different restoration scenarios, blue carbon's contributions to carbon neutrality are estimated at 2.23% (BAU), 2.33% (RCG), and 2.36% (MER), with sequestration efficiency exceeding global averages. This research not only addresses gaps in China’s blue carbon studies but also offers a methodological reference for evaluating blue carbon ecosystems' roles in climate mitigation globally. It supports blue carbon as an effective natural solution to climate change and provides theoretical guidance for the formulation of blue carbon conservation and restoration strategies.

Blue carbon; Carbon neutrality; Carbon stocks; Carbon sequestration; Contribution