Under the background of carbon peak and carbon neutrality, grassland carbon sinks are a key pathway to carbon neutrality. Based on the Coupled Model Intercomparison Project Phase 6 (CMIP6) climate scenario data, the Daycent model was used to simulate the carbon budget of Gansu grasslands from 2015 to 2100, and the trend analysis was used to study the spatial and temporal changes in grassland carbon budget in the next 78 years. The results revealed that, under the future climate scenario of SSP245, the net ecosystem productivity (NEP) indicated a non-significant fluctuating downward trend with a rate of -0.20 g·(m2·a)-1(in C, the same below), and the grassland carbon sink was in a declining state. Under the future climate scenario of SSP585, the grassland NEP indicated a significant fluctuating increase trend with a growth rate of 1.36 g·(m2·a)-1, and the grassland carbon sink gradually increased under this scenario; the spatial distribution of grassland carbon budget increased from northwest to southeast. The increase in temperature and precipitation under the SSP585 climate scenario was higher than that under the SSP245 climate scenario, and the grassland carbon budget strongly correlated positively with precipitation. However, a negative correlation was observed between grassland carbon budget and temperature. We identified the carbon sink intensity in Gansu grasslands under different climate conditions, which provides a reference for and contribution to effective carbon sequestration.
Keywords: Daycent model; carbon budget; climate conditions; spatiotemporal changes; trend analysis.