Slope Dynamics and Climate Change Through Indirect Interactions

The rapid variation of climate can cause direct changes in slope dynamics due to a modified rainfall regime. Variations in evapotranspiration regime determines changes in soil moisture, modifies shrinking-swelling cycles, creeping, surface mass movement, and soil erosion, including gully erosion. All these effects can be considered as direct consequences of any climate modification. Besides them, other indirect effects should be considered to fully determine climate change impact on slope dynamics. This is the case of the effects of climate change on vegetation, that strongly controls slope instability phenomena. Here we will concentrate on the effect of increased danger due to forest fire, and in particular we discuss the changes in the hydrogeological hazard linked to the effect of drought on wild fires in a case-study in Umbria (Italy), mainly considering field observations and simulations with LANDPLANER (LANDscape, Plant, LANdslide and ERosion) model. This study shows that when discussing of climate changes particular emphasis must be put on side effects that can influence slope dynamics and basin behavior. In particular the understanding of where threats can come, requires the identification of complex framework describing the dynamic interaction of all the elements coexisting in a slope.