A literature review on the methods for climate related coastal risk assessment in the Mediterranean region

The adverse effects of ongoing global warming on coastal areas are quite evident worldwide and the Mediterranean region is a perfect example of this scenario, being considered as a hotspot of climate change since in this area the short- and long- term impacts are expected to be stronger than in other areas of the world. In fact, the recent published “Assessment Report on Climate and Environmental Change in the Mediterranean” highlights that this region is warming 20% faster than the global average and that the current changes and future climate scenarios will point to a significant increase in climate-related risks during the next decades. In this context, the Mediterranean coastal areas are particularly prone to be affected by direct and indirect climate-related impacts including an increase in sea surface temperatures and ocean acidity, northward migration of marine species, changes in phytoplankton communities, and losses of ecosystem services. Many of these expected phenomena are related to coastal processes such as erosion, flooding, and saltwater intrusion, which, in turn, are strongly affected by increase in mean sea level, the most important slow-onset consequence of climate change. In the last decades, several studies have been focused on the evaluation of climate change impacts on coastal areas at the global and regional scale and, in particular, on the assessment of vulnerability and risk levels using different methodological approaches. On one hand, index-based methods are widely used being easy to be computed and providing stakeholders and planning authorities with useful and easy-to-read maps.  On the other hand, model-based approaches provided more detailed results but are less efficient in terms of time and computational efforts. With the aim of providing an updated state of art of the studies related to the assessment of both long- and short- term effects of climate change on coastal Mediterranean areas, with special reference to the methods and techniques applied for the evaluation of coastal vulnerability and risk, this work explores the available literature by searching Google scholar and Scopus platforms. In particular, the literature review was based on a number of keywords defined in the context of coastal hazard, vulnerability, and disaster risk reduction. The publications in close connection with the searched topics were selected and analysed. The results are shown in the form of graphs and maps, in order to highlight at the Mediterranean scale i) the most analysed coastal sectors, ii) the most common parameters used in the vulnerability and risk indices definition. Through this literature review, it becomes clear, how a sustainable management of coastal stretches would be possible through applying a holistic approach of risk assessment, which cannot ignore the interactions between multiple physical factors, related to social aspects, subaerial and marine processes. The key findings of the research emphasize how technological improvements and development of innovative methods for analysing the causes and effects of coastal risks sensitize local authorities to adopt relevant adaptation measures for coastal risk governance in the Mediterranean region.