Intra‐Annual Soil Erosion Variability in a Changing Climate: Influence of Vegetation Phenology Shifts and Rainfall Erosivity on Projected Monthly Soil Loss

ABSTRACT The objective of this study is to assess the future impact of climate change on soil erosion in Poland at a monthly scale. Using a Revised Universal Soil Loss Equation (RUSLE) modeling framework that integrates climate‐driven shifts in vegetation phenology and rainfall erosivity, we projected intra‐annual soil erosion dynamics under RCP4.5 and RCP8.5 scenarios for near (2041–2060) and far (2081–2100) future horizons. A novel method was developed to dynamically estimate the C factor based on the relationship between NDVI and accumulated temperature, enabling the simulation of climate‐responsive vegetation cover changes. Monthly rainfall erosivity projections accounted for the reduced erosivity of snowfall, improving winter estimates. The results indicate a substantial shift in the timing of erosion risk: spring soil loss is projected to decline due to earlier vegetation growth, while summer and late summer months—particularly August—show a high concentration of annual erosion (up to 40% under RCP8.5 for the far future). Total annual soil loss is projected to increase by 35%–60%, reaching up to 9.2 million tonnes year −1 under RCP8.5 for the far future. These findings highlight the importance of accounting for intra‐annual dynamics in soil erosion assessments and demonstrate that future soil conservation strategies must adapt to evolving seasonal patterns of erosion risk.