Climate change leads to significant loss of soil inorganic carbon

Soil inorganic carbon (SIC) pools are comparable in size to soil organic carbon pools and are vulnerable to climate change; however, SIC responses to climate change remain uncertain because of the lack of process-based simulations. Here, we developed a new process-based model integrating daily water balance dynamics with carbonate chemical equilibria at a 10 cm vertical resolution to predict the effects of climate change on the SIC pool down to a soil depth of 2 m in China until 2100. We found across the four shared socioeconomic pathways, SIC stock in China’s topsoil (0–10 cm) decreased by 314 ± 8 Tg C, accompanied by a loss of 217 ± 9 Tg C from the 2 m soils. These findings challenge the traditional view of SIC stability in terrestrial carbon cycles, reveal substantial losses of SIC in both topsoils and deep soils, and highlight the projection of future climate and global inorganic carbon cycle feedbacks.