Assessment and projection of mangrove blue carbon sink along the Guangdong coastline: integrating remote sensing and modeling techniques

Mangrove ecosystems along the Guangdong coastline serve as a vital blue carbon sink, yet their carbon sequestration potential under changing climatic conditions requires rigorous assessment and forward-looking evaluation. This study develops an integrated framework combining remote sensing techniques and spatial modeling approaches to quantify historical changes and project future trajectories of mangrove blue carbon stocks in Guangdong Province, China. Time-series satellite imagery was used to quantify changes in mangrove extent and associated carbon storage over the period 1994 to 2024. Field-validated sediment core data, coupled with the InVEST and CA-Markov models, were utilized to assess historical carbon storage and forecast future challenges along the coastline. Our results reveal substantial spatial variability in mangrove carbon storage across Guangdong. A non-significant increase in mangrove area was observed during the first decade of the study period (1994–2004). In contrast, a significant area expansion of 10.71% occurred between 2014 and 2024, with projections indicating a further increase of 19.45% by 2034. The eastern coast of Guangdong exhibited greater potential for mangrove expansion than the western coast. Based on the projected mangrove extent and the adopted carbon-density framework, the InVEST model estimated a potential 24.62% increase in mangrove carbon storage by 2034 relative to 2024. By explicitly integrating spatiotemporal remote sensing analysis with predictive land-use and carbon storage modeling, this study advances a scalable and transferable framework for assessing mangrove blue carbon dynamics under climate and development pressures. The findings provide critical evidence to inform adaptive coastal management, strengthen Guangdong's carbon neutrality goals, and support nature-based solutions for climate mitigation. Overall, this integrated approach provides a robust scientific basis for coastal spatial planning and offers actionable insights for conserving and enhancing mangrove blue carbon resources along this ecologically and economically important coastline.