• Energy Research

Changes in the main weather features are becoming perceivable in Italy. In the last years, the average temperature and the intensity of rainstorms are increasing. Such phenomena could lead to changes in the earth-atmosphere interaction. Accounting for the high vulnerability of the Italian territory, an obvious consequence would concern the effects on the hydro-geological hazards, including landslides and floods. As a matter of fact, the higher frequency of high magnitude flood and landslide events represent an alarm bell. It is necessary to explore with all available instruments the consequences of the potential climate changes. Since quantitative predictions are not possible, the only way to run is depicting rational scenarios for the most vulnerable contexts adopting a multidisciplinary approach. Based on projections of potential climate changes in the 21st century, the report examines their potential impact in the context of the Italian peninsula. After a general overview about typical slope responses to weather changes, some quantitative scenarios have been depicted for representative geomorphological contexts. The last part of the paper examines changes in the expected risk, based on the characteristics of the Italian territory and its vulnerability, looking at the initiatives to undertake for its mitigation.

Global warming is exacerbating flood hazards, making the robustness of flood risk management a critical issue. Without considering future scenarios, flood risk analysis built only on historical knowledge may not adequately address the coming challenges posed by climate change. A comprehensive risk analysis framework based on both historical inundations and future projections to tackle uncertainty is still lacking. In this view, a scenario-based, data-driven risk analysis framework that for the first time integrates recent historical floods and future risk trends is here presented, consisting of flood inundation-prone and high-risk zones. Considering the Poyang Lake Eco-Economic Zone (PLEEZ) in China as the study area, we reproduced historical inundation scenarios of major flood events by using Sentinel-1 imagery from 2015 to 2021, and used them to build the risk baseline model. The results show that 11.7% of the PLEEZ is currently exposed to the high-risk zone. In the SSP2-RCP4.5 scenario, the risk would gradually decrease after peaking around 2040 (with a 19.3% increase in high-risk areas), while under the traditional fossil fuel-dominated development pathway (SSP5-RCP8.5), the risk peak would occur with a higher intensity about a decade earlier. The attribution analysis results reveal that the intensification of heavy rainfall is the dominant driver of future risk increase and that the exploitation of unused land such as wetlands induces a significant increase in risk. Finally, a hierarchical panel of recommended management measures was developed. We hope that our risk analysis framework inspires newfound risk awareness and provides the basis for more effective flood risk management in river basins.

Earth observation (EO) data are useful tools to analyse geomorphological processes, among which slow-moving landslides triggered by rainfall. EO data are also used to evaluate climate change and to assess its impact on geomorphological processes and geo-hydrological phenomena. The latter is the topic of the Project OT4Clima (Innovative Earth Observation technologies to study Climate Change and its impact on the environment) joined by CNR-IRPI within a consortium that includes other CNR institutes, universities and private companies. The OT4CLIMA project moves from the awareness that the impacts of climate change on the environment need to be better observed, understood, and modelled, especially at a regional scale, in order to put in place appropriate and effective risk mitigation strategies. Within the project, the CNR-IRPI group works on the development of rigorous methods and procedures for evaluating the impact of climate and its change on landslides, in particular on those characterized by a slow cinematic, at a regional scale. The test site is represented by four catchments located in the Basilicata region, southern Italy, namely the basins of the Bradano, Basento, Agri, and Sinni rivers. Long-term rainfall series gathered from 22 rain gauges located in the four catchments are analysed to evaluate the presence of temporal trends. To this aim, non-parametric and statistical tests are applied to the series. Historical landslide information is gathered from the analysis of the IFFI (Inventario dei Fenomeni Franosi in Italia) database, the Idrogeo platform (https://idrogeo.isprambiente.it/app/) and the AVI (Aree Vulnerate in Italia) catalogue. Only some types of landslide movements are considered, namely rotational-translational slides, slow slides/flows, complex movements. Moreover, Copernicus Sentinel-1 images are employed to detect the spatial and temporal distribution of slow earth surface deformations. The obtained results are used for checking the completeness of the landslide inventories. More in detail, the deformation maps of the test site are obtained by means of the application of the SBAS (Small BAseline Subset) technique to three datasets of Sentinel-1 images: t146 ascending orbit and t51 and t124 descending orbits, for the period 2015-2020. Then, a comparative analysis of rainfall data with displacement series is carried out with the aim of identifying clusters of satellite measurements with homogeneous behaviour likely correlated to variations in the rainfall regime. In particular, only the points with a mean velocity in the observation higher than 0.1 cm/year are considered to be moving. Moreover, only the displacement series of points located in areas mapped as landslides - as for the historical inventories - and sited within the influence regions of each rain gauge in the study area are analysed. A 10-km circular buffer centred in the stations are used to define the influence region of each station. The displacement series are analysed and compared to the rainfall series to search for correlations and to evaluate the effects of climate drivers on slow moving landslides.

According to the fifth report of the Intergovernmental Panel on Climate Change, an increase in the frequency and the intensity of extreme rainfall is expected in the Mediterranean area. Among different impacts, this increase might result in a variation in the frequency and the spatial distribution of rainfall-induced landslides, and in an increase in the size of the population exposed to landslide risk. We propose a method for the regional-scale evaluation of future variations in the occurrence of rainfall-induced landslides, in response to changes in rainfall regimes. We exploit information on the occurrence of 603 rainfall-induced landslides in Calabria, southern Italy, in the period 1981-2010, and daily rainfall data recorded in the same period in the region. Furthermore, we use high-resolution climate projections based on RCP4.5 and RCP8.5 scenarios. In particular, we consider the mean variations between a 30-year future period (2036-2065) and the reference period 1981-2010 in three variables assumed as proxy for landslide activity: annual rainfall, seasonal cumulated rainfall, and annual maxima of daily rainfall. Based on reliable correlations between landslide occurrence and weather variables estimated in the reference period, we assess future variations in rainfall-induced landslide occurrence for all the municipalities of Calabria. A +45.7% and +21.2% average regional variation in rainfall-induced landslide occurrence is expected in the region for the period 2036-2065, under the RCP4.5 and RCP8.5 scenario, respectively. We also investigate the future variations in the impact of rainfall-induced landslides on the population of Calabria. We find a +80.2% and +54.5% increase in the impact on the population for the period 2036-2065, under the RCP4.5 and RCP8.5 scenario, respectively. The proposed method is quantitative and reproducible, thus it can be applied in similar regions, where adequate landslide and rainfall information is available.

According to the fifth report of the Intergovernmental Panel on Climate Change, "warming of the climate system is unequivocal". The influence of climate changes on slope stability and landslides is also undisputable. Nevertheless, the quantitative evaluation of the impact of global warming, and the related changes in climate, on landslides remains a complex question to be solved. The evidence that climate and landslides act at only partially overlapping spatial and temporal scales complicates the evaluation. Different research fields, including e.g., climatology, physics, hydrology, geology, hydrogeology, geotechnics, soil science, environmental science, and social science, must be considered. Climatic, environmental, demographic, and economic changes are strictly correlated, with complex feedbacks, to landslide occurrence and variation. Thus, a holistic, multidisciplinary approach is necessary. We reviewed the literature on landslide-climate studies, and found a bias in their geographical distribution, with several studies centered in Europe and North America, and large parts of the world not investigated. We examined advantages and drawbacks of the approaches adopted to evaluate the effects of climate variations on landslides, including prospective modelling and retrospective methods that use landslide and climate records, and paleoenvironmental information. We found that the results of landslide-climate studies depend more on the emission scenarios, the global circulation models, the regional climate models, and the methods to downscale the climate variables, than on the description of the variables controlling slope processes. Using ensembles of projections based on a range of emissions scenarios would reduce (or at least quantify) the uncertainties in the obtained results. We performed a preliminary global assessment of the future landslide impact, presenting a global distribution of the projected impact of climate change on landslide activity and abundance. Where global warming is expected to increase, the frequency and intensity of severe rainfall events, a primary trigger of shallow, rapid-moving landslides that cause many landslide fatalities, an increase in the number of people exposed to landslide risk is to be expected. Furthermore, we defined a group of objective and reproducible methods for the quantitative evaluation of the past and future (expected) variations in landslide occurrence and distribution, and in the impact and risk to the population, as a result of changes in climatic and environmental factors (particularly, land use changes), at regional scale. The methods were tested in a southern Italian region, but they can easily applied in other physiographic and climatic regions, where adequate information is available.

AbstractDuring the next few decades, changes in rainfall frequency and magnitude are expected to have major impacts on landscape evolution, social, and economic aspects of human society. We focus on seasonal rainfall variations by the end of the twenty-first century to define affected landslide-prone areas, future landslide alerts and the impact of landslides on landscape development in the juncture of the Alpine, Pannonian, and Mediterranean region. A moderate and a worst-case climate scenario from CMIP5 global climate simulations were considered to determine the impact of rainfall on the two most common types of landslides in region, shallow and deep-seated landslides. The observed changes in the occurrence of shallow landslides are significant, especially in the winter months, where we can expect more landslide-prone areas compared to the baseline period. Shallow landslides will have a greater impact on the landscape in spring and summer than deep-seated landslides, especially in vineyards.

Urbanization in hazardous regions, the abandonment of rural and mountain areas, and changed agricultural and forest practices have increased the impact of landslides through the years. Hence, the changing climate variables, like rainfall, acted and will act on a human-modified landscape. In this work, we analyze the role of rainfall variation and land use/cover change in the occurrence of landslides in Calabria in the period 1921-2010. Combining rainfall and landslide information, we reconstruct and analyze a catalogue of 1466 rainfall events with landslides (i.e., the occurrence of one or more landslide during or immediately after a rainfall event). To investigate the impact of land use/cover changes in the occurrence of landslides, we consider the "Land Use Map" made by the Italian National Research Council and the Italian Touring Club in 1956, and the "CORINE Land Cover" map released in 2000. Since our landslide catalogue is at municipality scale (i.e., for each landslide we known the municipality in which it occurred), we attribute a prevailing land use/cover class to each of the 409 municipalities of Calabria. We split the catalogue in two subsets (1921-1965 and 1966-2010) and correlate the landslides occurred in the first period to the 1956 land use and the landslides occurred in the second period to the 2000 land cover. We find that: (i) the geographical and the temporal distributions of rainfall-induced landslides have changed in the observation period; (ii) land use/cover in Calabria has changed between the two periods, with a huge decrease of arable land and an increase of heterogeneous agricultural areas and forests; (iii) in both periods, most of the landslides occurred in areas characterized by forests and arable land; (iv) in the second period, there was an increase (decrease) of landslides occurred in agricultural areas (arable land).

Cultural heritage is one of the most exceptional resources characterizing the Italian territory. Archaeological heritage, i.e., the archaeological sites with different types of archaeological artifacts, strongly contributes to enriching the national and international cultural heritage. Nevertheless, it is constantly exposed to external factors, such as natural deterioration, anthropic impact, and climate-related hazards, which may compromise its conservation. In Italy, many archaeological areas are affected by significant soil settlements that involve a large part of monuments. This paper focuses on the landslide hazard assessment of the archaeological site of Pietrabbondante (Molise region, Italy). The impact of the expected rainfall regimes, according to the EURO-CORDEX projections, on slope stability conditions were evaluated through the application of a physically based model that couples a hydraulic and a mechanical model to evaluate slope stability evolution due to pore pressure changes. Given the unavoidable lack of knowledge of the geotechnical soil properties in an archaeological heritage area, the proposed method considered the random uncertainty of soil parameters by means of a probabilistic approach in order to assess the stability conditions in terms of probability of occurrence of a landslide. The results of this study provide a reference for the safety assessment and preventive conservation of archaeological areas characterized by high cultural value.