Abstract Background China’s terrestrial ecosystems play a pronounced role in the global carbon cycle. Here we combine spatially-explicit information on vegetation, soil, topography, climate and land use change with a process-based biogeochemistry model to quantify the responses of terrestrial carbon cycle in China during the 20th century. Results At a century scale, China’s terrestrial ecosystems have acted as a carbon sink averaging at 96 Tg C yr− 1, with large inter-annual and decadal variabilities. The...