Changes in rainfall erosivity over mainland China under stabilized 1.5 ℃ and 2 ℃ warming futures

Abstract

Soil erosion is one of the major threats to the environment and agriculture in the world and rainfall erosivity is the most active factor to lead changes in soil erosion. Here, we use statistically downscaled, bias-corrected Community Earth System Model (CESM) low-warming simulations to investigate the future changes in rainfall erosivity in mainland China under the Paris Agreement global warming targets. The downscaled simulations evidently outperform the original CESM simulations in capturing the spatial distribution, magnitudes and annual cycle of rainfall erosivity in China in the present day (1986–2005). The rainfall erosivity will be significantly increased in most regions of China under the 1.5 °C and 2 °C warming targets and the regional mean increases are approximately 33% and 40%, respectively. In addition, the corresponding increases are even larger than 60% and 75%, respectively, in a quarter of mainland China. The increase in rainfall erosivity is resulted from the joint contributions of increases in frequency and intensity of erosive rainfall. However, it is dominated by the increase in the frequency. Compared with annual rainfall amount, the future warming will bring a four times greater impact on the soil erosion potentially caused by rainfall. Limiting global warming to 1.5 °C instead of 2 °C would reduce 17% of the increase in rainfall erosivity in China. For grain producing areas like Sichuan Basin, the middle and lower reaches of Yangtze River and South China, the values are approximately 20%. The future warming will significantly increase the potential risk of soil loss in China, and it is beneficial to relief this risk if the global warming is limited to 1.5 °C rather than 2 °C.