Future Evolution of Rainfall Erosivity in the Greater Alpine Region from Convection-Permitting Climate Models

Understanding future changes in rainfall erosivity is crucial for soil erosion management and related hazard mitigation in regions with complex topography. Rainfall erosivity is strongly controlled by short-duration precipitation characteristics, which are more realistically represented by convection-permitting climate models (CPMs) operating at convection-resolving scales, than by coarser regional models. Despite their advantages, CPM-based projections remain challenging due to limited simulation lengths and ensemble sizes. This study assesses projected changes in rainfall erosivity by analyzing both the intensity and the frequency of individual erosive rainfall events. The focus is on the Greater Alpine Region, a climatically and topographically heterogeneous area particularly sensitive to rainfall-driven erosion processes. An ensemble of nine CPM simulations from the CORDEX-FPS initiative at 3-km resolution is analyzed for a historical period (1996–2005), and a far future (2090–2099) under the RCP8.5 scenario.

The results indicate a widespread increase in projected rainfall erosivity across the region, driven by intensification of erosive rainfall events and, in some areas, by their increased frequency. Notably, the strongest relative increases are projected for high-elevation areas (particularly in the Eastern Alps), where present-day rainfall erosivity is comparatively low, while lowland regions, characterized by higher current erosivity, exhibit more moderate future changes. This altitudinal contrast points to a partial redistribution of erosive potential. These findings highlight a growing erosion risk in alpine environments under future climate conditions.