A robust assessment of rainfall erosivity changes over China through an ensemble of high-resolution climate models

Abstract Spatiotemporal variation in rainfall erosivity resulting from changes in rainfall characteristics due to climate change has implications for soil erosion in developing countries. It is of great significance to understand the past and future changes of rainfall erosivity and its implications in different regions of China on a national scale to promote soil and water conservation planning. In this paper, China is divided into eight first-class areas of soil and water conservation zoning. The multi-climate model and multi-emission scenario approach to characterize the spatiotemporal projection of rainfall erosivity and assess variations of rainfall erosivity in China consists of 5 regional climate models (RCMs) and two Representative Concentration Pathway 4.5 and 8.5 (RCP4.5 and RCP8.5) scenarios for the baseline period (1986-2005) and future periods (2071-2090). The result indicates that compared with observational data, the performance of the MCLM and PRECIS is better than other models in reproducing the spatial distribution and annual cycle of rainfall erosivity in China. There is an increasing trend in the annual rainfall erosivity from the baseline climate up to the RCMs, for all the RCMs, with an average change in erosivity of about 13.0% and 22.1% under RCP4.5 and RCP8.5 respectively. Under the RCP 8.5 scenario, the absolute value of rainfall erosivity increased by 797.8 and 969.7 MJ·mm·hm-2·h-1 respectively in the South China red soil region and the North China mountainous region, indicating that climate warming will greatly enhance the potential erosion capacity of rainfall in these two areas. Meanwhile, the Southwest China karst region and Qinghai Tibet Plateau region are more sensitive to radiation forcing. According to the changes in rainfall erosivity, local soil conditions, vegetation coverage, and other factors in different regions, taking soil and water conservation measures is conducive to reducing the risk of soil erosion caused by climate change.