Estimating future landslide hazards from km-scale greenhouse warming simulations

Landslides in mountainous regions are major climate-related hazards that are expected to increase in frequency with greenhouse warming and intensified rainfall. Coarser-resolution Earth System models participating in the Coupled Model Intercomparison Project are not adequate to resolve atmospheric responses in steep terrains, such as the Himalayas or the Andes. Here, we use km-scale, global cloud-resolving greenhouse warming simulations conducted with the coupled OpenIFS-FESOM2 model (AWI-CM3) to investigate how extreme rainfall and soil moisture characteristics in steep mountain regions change in response to greenhouse warming. Precipitation extremes, along with large-scale atmospheric dynamics, are analyzed across different slope angles to diagnose orographic lifting and convective enhancement mechanisms. Our findings reveal a pronounced increase in high-intensity precipitation on slopes steeper than 30°, particularly in the Himalayas and the Andes, with significant implications for future rain-induced landslides. This increase is primarily driven by thermodynamic changes rather than by relatively weak upslope motion. By using high-resolution (9 km) and higher-resolution (4 km) simulations, we provide a robust framework for enhancing global landslide hazard assessments in the context of climate change.