Carbon Sequestration Potential of China’s Terrestrial Ecosystem Incorporating Moisture Recycling

Terrestrial ecosystems play a critical role in achieving carbon neutrality, yet the carbon sequestration potential (CSP) of China’s terrestrial ecosystems remains incompletely characterized, particularly regarding the roles of future climate scenarios and land–atmosphere moisture feedbacks. Here we quantify China’s CSP using a process-based model (LPJ-GUESS) that explicitly simulates vegetation dynamics, combined with potential natural vegetation (PNV) benchmarks and moisture recycling. We estimate China’s historical (1993–2022) actual terrestrial (AT) carbon stock at 91.7 PgC, with a PNV ceiling of 132.9 PgC, yielding a CSP of 41.2 PgC. Under future scenarios (2071–2100), CSP follows a non-linear trajectory. Relative to the historical baseline, it declines slightly under SSP119, peaks under SSP2-4.5, and remains elevated but slightly reduced under SSP5-8.5. High-CSP areas are concentrated along the Hu Line and the belts of the Tianshan, Kunlun, and Qilian mountains, while scattered areas in southern China exhibit negative CSP due to intensive human interventions. Moisture recycling consistently enhances CSP across all periods and scenarios. Historically, it raised national CSP by approximately 5 PgC, and this enhancement gradually weakens to 4 PgC under SSP119 and further declines to around 2 PgC under SSP2-4.5/SSP5-8.5—revealing that high emissions erode this positive feedback. Our findings identify a critical window for maximizing restoration gains under moderate forcing (SSP2-4.5) and demonstrate that low-to-moderate emission pathways not only preserve direct carbon benefits but also safeguard indirect moisture recycling amplification. Regionally tailored restoration strategies accounting for moisture recycling are essential for achieving China’s 2060 carbon neutrality goals.