A severe landslide event in the Alpine foreland under possible future climate and land-use changes

Landslides are a major natural hazard, but uncertainties about their occurrence in a warmer climate are substantial. The relative role of rainfall, soil moisture, and land-use changes and the importance of climate change mitigation are not well understood. Here, we develop an event storyline approach to address these issues, considering an observed event in Austria with some 3000 landslides as a showcase. We simulate the event using a convection permitting regional climate model and a statistical landslide model at present and a range of plausible future climate and land use conditions. Depending on the changes of rainfall and soil moisture, the area affected during a 2009-type event could grow by 45% at 4 K global warming, although a slight reduction is also possible. Such growth could be reduced to less than 10% by limiting global warming according to the Paris agreement. Anticipated land-use changes towards a climate-resilient forest would fully compensate for such a limited increase in hazard. The area affected by a landslide analogous to an Alpine foreland event in 2009 could be up to 45% larger under 4 K of global warming, or 10% if warming is limited in line with the Paris Agreement, according to simulations of event storylines with varying climate, soil moisture and land use.

Automated summary

This study addresses the uncertainties and relative impacts of rainfall, soil moisture, and land use changes on landslide occurrences by simulating a showcase event in Austria under different climate conditions. It reveals that the area affected by landslides could significantly increase under global warming, but limiting warming according to the Paris Agreement could reduce the growth. Additionally, land use changes towards climate-resilient forests could compensate for the limited increase in hazard.