Soil erosion responses to climate change in a tropical monsoon‐dominated river basin ‐ A geospatial perspective

Soil erosion is a major global environmental and socio‐economic challenge, with impacts particularly severe in tropical, monsoon‐dominated mountainous regions, where heavy rainfall, steep terrain, and unsustainable land‐use practices accelerate land degradation. The Chalakkudy River Basin in central Kerala represents an ecologically sensitive landscape of the Western Ghats, highly vulnerable to soil erosion due to its diverse physiography, intense monsoonal climate, and increasing anthropogenic pressures. This study evaluates current soil loss and projects potential future soil losses under changing climatic conditions using geospatial techniques integrated with the Revised Universal Soil Loss Equation (RUSLE). Future erosion risks were assessed by analyzing projected trends in rainfall erosivity under three Representative Concentration Pathways (RCP 2.6, 4.5, and 8.5). The results reveal pronounced spatial variability in soil loss across the watershed, with higher erosion rates concentrated in areas of steep slopes, reduced vegetation cover, and disturbed land uses such as deforested hillslopes and plantation zones. In contrast, forested regions and gentle slopes exhibited comparatively lower erosion susceptibility. Under the high‐emission scenario (RCP 8.5), soil erosion is projected to increase substantially, with the upper and midland regions of the basin emerging as critical hotspots, driven by intensifying rainfall erosivity and the heightened sensitivity of disturbed landscapes to climate forcing. Erosion hotspots were predominantly identified in deforested highlands, plantation belts along the Western Ghats slopes, and lowland catchments lacking adequate conservation measures. The findings demonstrate that climate change is likely to intensify soil erosion risk across the Chalakkudy Basin, particularly under scenarios associated with greater warming and increased rainfall extremes. These results underscore the insistent requirement of targeted soil and water conservation interventions, including site‐specific measures in erosion‐prone hotspots, to minimize nutrient‐rich topsoil loss and its associated carbon depletion under evolving climatic conditions. This study provides climate‐sensitive erosion projections for a highly vulnerable tropical monsoon‐dominated basin, offering critical insights for climate‐resilient land‐use planning, watershed management, and sustainable soil conservation in Kerala and other comparable tropical regions.