Mass-Movements and Climate Change

Although mass-movements can be caused by a variety of natural phenomena and human actions, in most areas of the world rainfall is their primary trigger. An often-neglected complication of the operational forecasting of rainfall-induced landslides is global warming, in particular the related ongoing and expected changes in rainfall and temperature. The evaluation of the effects of the current and the projected climate change on the stability/instability conditions of natural and engineered slopes remains complicated. In this chapter, we address the main questions related to the assessment of the impact of climate change on mass-movements. Starting from the results of a review of studies on the topic, we analyze and discuss how climate factors (and their changes) influence slope stability conditions and landslide hazard. This is not trivial, due to multiple reasons, including the fact that (i) the temporal and the geographical scales of climate and landslides are very different; (ii) different climate variables affect landslides; (iii) landslides are complex and diversified phenomena that respond differently to changes in climate. Moreover, we outline the main research needs and we provide general and specific recommendations for the operational forecasting of rainfall-induced landslides considering the current and the expected changes in climate. In particular, a holistic approach is needed to understand and measure how climate variables and their variability affect mass-movements, and to provide useful projections that will allow effective short- and long-term actions to reduce landslide risk.