Modelling evaluation of the impact of Medicane Apollo on pocket beaches in the context of climate change

The climate crisis represents a significant threat to the Mediterranean regions, with potential repercussions on the environment, economy (e.g. tourism) and society. Rising global temperatures are responsible not only for the melting of glaciers and resulting rise in sea level, but also for the increasing temperature of the oceans. Future scenarios projected by the Intergovernmental Panel on Climate Change (2021) for the Mediterranean basin indicate a sea level rise of about 0.3 meters by 2050, with a potential doubling by 2100 with respect to 1900. In terms of temperature, an increase of between 2 and 5 degrees Celsius is expected with respect to 1900. These climate changes are capable of generating extreme weather events, including tropical-like cyclones and extratropical cyclones. While an increase in the frequency of these events has not been observed, there has been an increase in their intensity. . The impact of these events on coastlines can lead to coastal erosion, habitat loss, flooding of urban and agricultural areas and salinisation of aquifers, which, in turn, can affect availability of freshwater, safety risks and significant economic losses.

In this study, the potential impact of a Mediterranean hurricane (known as a medicane) was modelled in relation to future sea-level rise scenarios along the east coast of Sicily. In particular, the study considered the potential impact on a selection of pocket beaches that are of significant natural and tourist interest. Such beaches are particularly vulnerable due to their susceptibility to significant alterations in sediment deposition and erosion, especially during events such as medicanes. In the most extreme cases, these beaches  can be completely lost. Due to their nature, once lost these beaches do not recover naturally. In order to model  the future medicanes' scenarios that are likely to impact  the east coast of Sicily, the Medicane Apollo (2021)  was consider as a benchmark. The intensity parameters (as mean sea-level pressure and wind speed) of the Medicane Apollo were extracted from reanalysis products of ERA5. Subsequently, the Delft3D software was used to simulate significant wave heights and water levels, taking into account both the forcing conditions that occurred during the Medicane Apollo and the future conditions predicted for 2050 and 2100 by the IPCC (2021). XBeach was used for the modelling of coastal flooding in the proximity of nearshore zones of the pocket beaches. The Sicilian pocket beaches represent an important tourist attraction and it is crucial to preserve them. This work can contribute to the assessment of the vulnerability of the pocket beaches to extreme weather events, providing useful information aimed at developing strategies for their protection.