11 - Physical impacts of climate change on landslide occurrence and related adaptation

Summary

Abstract

We review current understanding of the effects of climate change on the occurrence of landslides and debris flows in cold, temperate, and tropical mountains. We start with a summary of observed impacts of climate change on shallow landslides and debris flows, followed by discussions of rock-slope failures and the physical processes that make climate an important cause and trigger of landslides. While an increase in extreme precipitation has been observed in many regions worldwide over the past decades, changes in frequency and magnitude of landslides are more difficult to identify. In high mountain regions with snow, glaciers, and permafrost, slope stability is sensitive not only to changes in precipitation but also to changes in temperature. In the European Alps, the number of high alpine rock-slope failures has increased over the past few decades, coincident with an increase in mean air temperature. Model-based projections of future climate indicate that extreme precipitation events are likely to increase, causing more landslides. Seasonal variations in precipitation and earlier snowmelt imply changes in the seasonality of landslide occurrence. In addition, changes in sediment supply can strongly condition debris-flow frequency and magnitude. We conclude with a case study that outlines the potential and limitations of adaptation to future changes in precipitation.