Synergistic impacts of climate and land use/land cover changes on the spatiotemporal evolution of landslides in Kerala

Climate change and land use/land cover (LULC) transitions are increasingly influencing landslide dynamics in mountainous regions, yet their combined effects remain insufficiently quantified. This study evaluates the joint impacts of future climate and LULC changes on landslide susceptibility in Kerala, India, during 2026–2035. An improved physically based TRIGRS landslide susceptibility model was integrated with future LULC scenarios simulated using the PLUS model and precipitation projections from the bias-corrected and statistically downscaled NEX-GDDP-CMIP6 dataset under the SSP2-4.5 scenario. The LULC simulations were validated through historical hindcasting, while the climate projections were evaluated against the baseline period. Hydro-mechanical parameters were dynamically adjusted to represent vegetation-related effects on root cohesion, biomass loading, and saturated hydraulic conductivity. The model demonstrated strong predictive capability for the baseline period (AUC = 0.91). The results under the SSP2-4.5 scenario suggest that intensified extreme rainfall will substantially increase landslide susceptibility, with high and very high susceptibility zones expanding by 2.66% and 8.97%, respectively, by 2035. LULC change exhibits localized and phase-dependent influences. However, uncertainties remain due to future climate scenarios, LULC simulations, and model assumptions. These findings provide a practical framework for landslide susceptibility assessment under environmental change and support climate adaptation strategies in South Asia.