Carbon Sink of Terrestrial Ecosystems in China During 2010–2020: Spatiotemporal Variability and Climate Impact

Abstract

Carbon neutrality in China can be achieved through maintained and improved terrestrial carbon sinks. However, the impact of climate change on the carbon cycle remains unclear. Here, we assess the spatiotemporal dynamics of net ecosystem productivity (NEP) in China's terrestrial ecosystems from 2010 to 2020 and its response to climate change using the regional climate-chemistry-ecology coupled model RegCM-Chem-YIBs. The estimations demonstrate that the national annual average NEP was 399.08 TgC yr⁻¹ and increased by 8.83 TgC yr⁻¹, effectively offsetting 15.4% of industrial carbon emissions. The NEP decreased gradually from southeast to northwest, with the maximum occurring in the southwest (122.31 TgC yr⁻¹); the NEP intensity peaked in summer (102.31 gC m⁻² yr⁻¹). Climate change positively contributed to NEP (11.2 TgC yr⁻¹), with significant interannual and regional differences. Precipitation anomalies in the southern region are the main meteorological factor for the interannual fluctuation of NEP. The increase in radiation led to an increase in NEP of 4.85 TgC yr⁻¹ and dominated 46.49% of the region in China. The increase in NEP in the southern region was attributed to enhanced radiation, while the northern region benefited from increased precipitation and rising temperatures. These findings highlight the significant spatiotemporal variations in the impact of climate change on the carbon sinks of terrestrial ecosystems in China. It is essential to account for the effects of climate change and to adopt differentiated strategies to enhance carbon sinks during policy formulation.