Historical and future variation of soil organic carbon in China

•The SOC in two depths were mapped at a resolution of 1 km and five-year interval during 1980–2100.•Three climate scenarios of SSP 1–1.9, SSP2-4.5 and SSP5-8.5 in CMIP6 were considered.•The top 20 cm and 100 cm SOC of China both acted as carbon sinks during 1980–2020.•The SOC will fluctuate significantly in the future under different climate scenarios.•Under the SSP2-4.5 scenario, SOC presented a larger likelihood of being a carbon source in most region.