The responses of weathering carbon sink to eco-hydrological processes in global rocks

Abstract Eco-hydrological processes affect the chemical weathering carbon sink (CS) of rocks. However, due to data quality limitations, the magnitude of the CS of rocks and their responses to eco-hydrological processes are not accurately understood. Therefore, based on Global Erosion Model for CO2 fluxes (GEM-CO2 model), hydrological site data, and multi-source remote sensing data, we produced a 0.05° × 0.05° resolution dataset of CS for 11 types of rocks from 2001 to 2018. The results show that the total amount of CS of global rocks is 0.32 ± 0.02 Pg C, with an average flux of 2.7 t C km-2yr-1, accounting for 53% and 3% of the “missing” carbon sink and fossil fuel emissions, respectively. This is 23% higher than previous research results, which may be due to the increased resolution. Although about 60% of the CS of global rocks are in a stable state, there are obvious differences among rocks. For example, the CS of carbonate rocks exhibited a significant increase (0.30 Tg C/yr), while the CS of siliceous clastic sedimentary rocks exhibited a significant decrease (−0.06 Tg C/yr). Although temperature is an important factor affecting the CS, the proportion of soil moisture in arid and temperate climate zones is higher (accounting for 24%), which is 3.6 times that of temperature. Simulations based on representative concentration pathways scenarios indicate that the global CS of rocks may increase by about 28% from 2050 to 2100. In short, we produced a set of high-resolution datasets for the CS of global rocks, which makes up for the lack of datasets in previous studies and improves our understanding of the magnitude and spatial pattern of the CS and its responses to eco-hydrological processes.