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, comprises diverse landforms and a relatively fragile environment, contributing significantly to national food production and ecological security. Soil erosion in this region undermines cropland productivity and threatens soil and water conservation efforts. Under global climate change, increasing frequency and intensity of extreme precipitation events are expected to alter spatiotemporal patterns of rainfall erosivity, intensifying regional soil erosion risks. To assess future rainfall erosivity trends, five Coupled Model Intercomparison Project Phase 6 (CMIP6) precipitation datasets were used alongside a daily rainfall erosivity covering near (2021–2060) and far future (2061–2100) periods, and annual erosive rainfall days and intensity were also evaluated. Compared to single-model simulations, using a multi-model ensemble can effectively reduce uncertainties in climate projections and improve the robustness of the results. The ensemble mean of the five CMIP6 models was adopted for future projections. 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 increase under the high-emission scenario. Compared with the baseline period, the multiyear mean annual rainfall erosivity is projected to increase by 11.50% and 15.21% in the near future under the low- and high-emission scenarios, respectively, and by 17.20% and 33.32% in the far future. 2) In future, the multiyear mean annual number of erosive rainfall days and intensity both increased 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 revealed that changes in rainfall erosivity were particularly pronounced in spring and winter, warranting future attention. 3) Compared with 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 and far futures, respectively. Adoption of low-emission strategies is essential to limit future erosive rainfall frequency and intensity, thereby reducing the potential soil erosion risk in the Yellow River Basin.