Assessing climate change effects on the occurrence of hydrological landslides in Emilia Romagana ( Italy) region

Over the past few decades, clear evidence has underlined that global climate has changed and this trend is projected to continue in the future. As a consequence, climate change concerns an increase in temperature and variations in rainfall patterns, which may be responsible for changes in landslide occurrences. In principle, landslide is supposed to respond to climate change correspondingly. However, the influence of climate change on landslide occurrences has not been defined quantitatively yet and whether the effect could exacerbate or reduce landslides impact on a regional scale is still unclear. Thus, this study aims to employ several meteorological factors to serve as a bridge to explore the intrinsic correlation between climate change and landslide occurrences.

To demonstrate the methodology, this paper illustrates the Emilia-Romagna region (Italy, historic data from 1979 to 2019) as a case study due to its high quality observation over past decades Firstly, we carry out an explorative temporal and spatial distribution characteristic analysis of meteorological factors including temperature, precipitation, evaporation and soil moisture to explore its change rule. In addition, data derived from the ERA5 dataset is calibrated with the observed data in the targeted zones in order to yield thresholds to estimate landslide risk. By using two types of thresholds, relationships between climate parameters and consequences such as landslide triggering, landslide event frequency, and landslide event magnitude are established. Furthermore, we calculate the exceedance probabilities and forecast the overall trend of occurrence of landslide influenced by climate change in the future.

The results show that there is an overall upward trend in the annual average temperature and soil moisture is found to decrease throughout these years; Hilly areas are more sensitive to changes in both temperature and precipitation compared with the coastal areas which is consistent with the variation of landslides occurence . The results provide useful foundation for further hydrological landslide risk management in the region.