High-Resolution Assessment of Terrestrial Carbon Storage and Restoration Benefits in China, 1990-2023

Terrestrial ecosystems serve as critical carbon sinks, playing an important role in the global carbon cycle and climate regulation. However, previous estimates of carbon storage in China's terrestrial ecosystems remain uncertain due to variability in data sources and methodological approaches. This study integrates multisource remote sensing data with extensive field-sampling data sets of carbon density, leveraging machine learning models to provide a comprehensive estimation of multiyear carbon storage and annual dynamics across multiple carbon pools. We estimated project-region carbon-stock changes using a scenario-based accounting framework. The total carbon storage, encompassing vegetation biomass and soil organic carbon, is estimated at 113.48 Pg C, with 20.4% in vegetation biomass and 79.6% in soil. Across land-use types, forests store the largest share, with 47.99 Pg C, followed by grasslands, croplands, barren lands, shrublands, and wetlands, which stored 32.32, 18.00, 14.65, 0.49, and 0.02 Pg C, respectively. National carbon stocks fluctuated over the study period but increased by 6.62 Pg C from 2014 to 2023. Scenario-based accounting indicates an additional baseline-adjusted project-region carbon-stock gain of 0.495 Pg C within major restoration regions during 2014-2023, equivalent to 0.050 Pg C yr-1. These results provide a high-resolution reconstruction of China's terrestrial carbon stocks and clarify recent carbon-stock changes across ecosystems, regions, and major restoration areas.