Climate Change Impacts on Soil Erosion in a Tropical Watershed: Insights from SINGV Regional Climate Modelling and RUSLE

<ns7:p> Abstract* Background Soil erosion is a major environmental challenge in tropical watersheds, where intense rainfall, complex topography, and land-use dynamics accelerate land degradation. Climate change is expected to intensify these processes by altering precipitation patterns and increasing rainfall erosivity. Methods This study assesses the impact of climate change on soil erosion in the Biyonga sub-watershed, Indonesia, by integrating bias-corrected regional climate model projections with the Revised Universal Soil Loss Equation (RUSLE). Climate model performance was evaluated against observed rainfall data, and corrected precipitation was used to estimate baseline and future erosion under SSP245 and SSP585 scenarios. Results The results indicate an increase in soil erosion of approximately 6.12–8.83 t ha <ns7:sup>−1</ns7:sup> yr <ns7:sup>−1</ns7:sup> under future climate scenarios. Mean erosion rates are projected to reach 46.33–49.03 t ha <ns7:sup>−1</ns7:sup> yr <ns7:sup>−1</ns7:sup> , with higher values under SSP585. Steep upstream areas emerge as dominant erosion hotspots, strongly influenced by high slope length and steepness (LS) factors. Moderate erosion (Class II) remains the dominant category, covering about 54–56% of the watershed, while more than half of the area shows increasing erosion trends. Conclusions Climate change is projected to amplify existing erosion patterns rather than fundamentally alter their spatial distribution. Integrating climate projections with spatial erosion modelling provides valuable insights for identifying vulnerable areas and supports adaptive watershed management in tropical environments. </ns7:p>