Assessing the Potential Impact of 1.5 ℃ Global Warming on the Local Response of a Pyroclastic Cover Susceptible to Shallow Landslides

In the Campania region (southern Italy), shallow landslides frequently involve steep slopes covered by loose pyroclastic soil in unsaturated conditions, causing several fatalities. For these phenomena, the slope response to heavy rainfall depends on the hydraulic state within the soil cover before the rainstorm. A clear indicator of such a state is the water storage (WS, the mean value of the integral of the water content in a unit base soil column). Hence, a threshold in terms of WS may be used in physically based predictive models. This work illustrates a framework to analyse the potential changes, due to global warming, in weather patterns regulating the slope atmosphere interaction (namely, precipitation and temperature) and the associated changes in WS, in pyroclastic slope susceptible to shallow landslides. A pyroclastic slope monitored for two years, placed on Mt. Faito (Lattari Mts. in Southern Italy) close to ancient flow-like landslides has been adopted as the pilot site. The slope hydraulic behaviour under the future temporal horizon and reference period has been modelled by Finite Element (FE) code. The future temporal horizon is identified assuming a fixed increase in global warming: in the specific, 1.5 ℃ defined in the Paris Agreement (2015) to preserve human and ecosystem livelihood on the Earth. The variations in WS are compared between the 1.5 ℃ scenario and the reference period 1981–2010. For the investigated case, the results of analyses under an “optimistic” global scenario, show that the number of events potentially leading to slope instability could not be affected significantly.