Coastal human-induced changes in the context of Climate Change: the case study of South-East Sicily

Coastal areas are highly dynamic environments, and their behaviour is the complex result of multiple processes occurring and interacting on a variety of time and spatial scales. However, human interventions have become driving coastal change forces as natural physical processes over the last decades and the increasing coastal urbanization is significantly modifying coastal dynamics. As such, coastal management should provide prompt and efficient predictive tools for coastal development to protect them from erosional and flooding risks. Past shoreline evolution studies are thus the base tools to assess coastal variability and forecast future trends. Here, the study on the shoreline evolution of the south-eastern coastal area of Sicily (Italy) is presented. The south-eastern coastal area is characterized by a coastal lagoon system that can provide a wide buffer zone for the beach and together with dune ridges represent a significant sediment reservoir. The shoreline change analysis was performed over the time between 1955 and 2021, considering oceanographic variables and coastal human-induced changes. The south-eastern Sicilian coast is well-known to be a densely populated area highly sensitive to natural risks (e.g. tsunami, flooding, sea-level changes). The Digital Shoreline Analysis System (DSAS), a free application of the ESRI ArcGIS© software, was used to compute the shoreline migration rates (SCE, NSM, EPR, LRR, WLR) over the considered time range coupled with the assessment of the coastal land use analysis performed by the Corine Land Cover program maps. The shoreline evolution analysis showed that more than 75% of the coasts experienced landward migration with an average WLR value of -0.5 m/year and that the highest erosional values were recorded where both such natural processes (subduction, sediment supply changes) and human-induced disturbance (loss of dune ridge, coastal armouring, increasing urbanization and cultivation) took place.