Rainfall-induced landslide: an indicator of the effects of climate change

The impact of climate change on the severity and frequency of weather-related hazards is leading to a growing need for multi-hazard studies. The rainfall-induced landslides present a significant risk at local scale, leading to devastating impacts on the built environment and fatalities. The evolution of landslide risk with climate change remains a challenge because of the complex interactions between land parameters and precipitations. To estimate trends in landslide hazard evolution due to modification of rainfall pattern, a framework using a univariate threshold method is developed and applied to Italy. This study employs the LHASA model (Kirschbaum and Stanley, 2018), the ERA5 reanalysis data and climate projections, to determine a precipitation threshold and to assess the dynamic evolution of rainfall-induced landslide triggering. The ITAlian rainfall-induced LandslIdes CAtalogue (ITALICA) is used to evaluate the performance of the model. The 30 years precipitation threshold enables to predict 92% of the events, with a better performance over debris flow. The average number of annual days at risk over 30 years is used to project the propensity of rainfall-induced landslide to be triggered. The spatial and temporal evolution of landslide induced hazard is then analyzed over the SSP2-4.5 and SSP5-8.5 climate scenarios. The framework identifies areas where the landslide hazard increases relatively strongly over all the climate scenarios.