UNESCO World Heritage sites in the Mediterranean (including Venice, the Piazza del Duomo in Pisa, and the Medieval City of Rhodes) are under threat of coastal erosion and flooding owing to sea-level rise, reports a paper published in Nature Communications this week. The study presents a risk index that allows ranking of the sites according to their risk from coastal hazards owing to sea level rise until the end of the century.

The Mediterranean region has a high concentration of UNESCO World Heritage sites, many of which are in coastal locations. Sea-level rise poses a threat to these sites however, information on the risk at a local level is needed for adaptation planning.

Lena Reimann and colleagues combine model simulations with World Heritage site data to develop an index to assess the risk of both coastal flooding and erosion due to sea level rise at 49 coastal Mediterranean UNESCO World Heritage sites by the end of the century. They find that of the sites, 37 are at risk from a 100-year flood event (a flooding event which has a 1% chance of happening in any given year) and 42 from coastal erosion today. By 2100, flood risk may increase by 50% and erosion risk by 13% across the region, and all but two of the sites (Medina of Tunis and Xanthos-Letoon in Turkey) will be at risk from one of these hazards.

The study identifies areas with urgent need for adaptation planning and the authors suggest the iconic nature of such sites could be used to promote awareness of the need for climate change mitigation.