Projecting changes in rainfall erosivity in the Yellow River Basin based on CMIP6 models

The Yellow River Basin, a crucial agricultural and ecological region in China, features diverse landforms and a relatively fragile environment. It plays an essential role in ensuring national food and ecological security. However, soil erosion not only undermines cropland productivity but also poses a significant threat to soil and water conservation as well as overall ecological stability. In the context of global climate change, the frequency and intensity of extreme precipitation events are projected to continue increasing, thereby altering the spatiotemporal patterns of future rainfall erosivity and exerting profound impacts on regional soil erosion processes. Therefore, accurately quantifying the spatiotemporal variations of future rainfall erosivity is of great significance for scientifically assessing potential soil erosion risks. This study is based on five Coupled Model Intercomparison Project Phase 6 (CMIP6) precipitation datasets and employs a daily rainfall erosivity model to project changes in rainfall erosivity in the Yellow River Basin for the near future (2021–2060) and the far future (2061–2100. The changes in annual erosive rainfall days and intensity are also analyzed. Compared with single-model simulations, using a multi-model ensemble can effectively reduce uncertainties in climate projections and improve the robustness of the results. Therefore, this study adopts the ensemble mean of five CMIP6 models as the future dataset. The results indicate that 1) under both future emission scenarios, rainfall erosivity exhibits an overall increasing trend in the Yellow River Basin, with a more pronounced rise under the high-emission scenario. Compared to the baseline period, multi-year mean annual rainfall erosivity is projected to increase by 11.50% and 15.21% in the near future under the low-emission and high-emission scenarios, respectively, and by 17.20% and 33.32% in the far future. 2) In future periods, the multi-year mean annual number of erosive rainfall days and intensity both increase relative to the baseline period, with the largest increases occurring in the far future under the high-emission scenario, reaching 27.55% and 4.71%, respectively. Seasonal analysis reveals that the changes in rainfall erosivity are particularly pronounced in spring and winter, which warrants attention in the future. 3) Compared to the high-emission scenario, the low-emission scenario can effectively mitigate the increase in rainfall erosivity, reducing the projected rise by 2.88% and 17.51% in the near future and far future, respectively. The implementation of low-emission strategies can help curb the future increase in both the frequency and intensity of annual erosive rainfall, thereby reducing the potential soil erosion risk in the Yellow River Basin.