World Heritage Sites threatened by rising sea levels

In the Mediterranean region, there are numerous UNESCO World Heritage Sites in low-lying coastal areas. In the course of the 21st century, these sites will increasingly be at risk by storm surges and increasing coastal erosion due to sea-level rise.large number of the altogether 49 World Heritage Sites investigated are at risk due to rising sea levels. Up to 37 of these sites are at risk from a so-called 100-year storm surge, which has a 1 percent chance of being exceeded in any given year. 42 of the 49 sites are at risk from coastal erosion

 If sea levels continue rising further, "in the Mediterranean region, the risk posed by storm surges, which are 100-year storm surges under today's conditions, may increase by up to 50 percent on average, and that from coastal erosion by up to 13 percent -- and all of this by the end of the 21st century under high-end sea-level rise. Individual World Heritage Sites could even be affected much more due to their exposed locationThe increase in flood risk of up to 50 percent and erosion risk of up to 13 percent are based on an assumed average sea-level rise in the Mediterranean region of 1.46 meters by the year 2100. This increase could occur with a five percent probability (95th percentile) under a high-end climate change scenario (RCP8.5). "Even if such a high sea-level rise has a low probability of occurring by the year 2100, this scenario cannot be ruled out, due to the high uncertainties in relation to the melting of the ice sheets," said Professor Vafeidis. "In addition, such a scenario is quite relevant from a risk management perspective, since a 5% probability in this context is not low."