Simulation and Prediction of Vegetation Carbon Flux under SSP Scenarios in Beijing

• • Biome-BGC model successfully simulated historical (2001–2014) GPP and NPP in Beijing, with annual means ranging 584–777 g C m−2 a−1 and 238–388 g C m−2 a−1, respectively, validating its applicability for regional carbon flux assessment. • • Under SSP585, GPP is projected to increase by 376 g C m−2 a−1 by 2070, compared to 171 g C m−2 a−1 under SSP126, indicating that higher emission scenarios may enhance vegetation productivity in Beijing. • • Annual mean temperature is the primary meteorological driver of GPP and NPP trends, with secondary influences from solar radiation and precipitation, while relative humidity shows minimal correlation. • • Future carbon use efficiency (CUE) is projected to be approximately 0.45, slightly lower than historical levels, suggesting that while Beijing's ecosystems retain strong carbon sequestration potential, increased respiration under warming may reduce efficiency.