Sea level along the Mediterranean coast has risen 6 cm. It will rise 50 cm by 2100. Climate change is already threatening some of the Mediterranean’s most treasured historical sites. more than 90 percent of the region’s World Heritage sites are at risk now from sea-level rise and coastal erosion. By the end of the century, 47 of the Mediterranean’s 49 sites—and some of the oldest remaining markers of the history of human civilization—will be in jeopardy. The most vulnerable sites to sea-level rise and coastal erosion include Venice, with its network of intersecting canals and the city of Tyre, an ancient Phoenician metropolis and cultural hub, which sits on a tiny peninsula jutting directly into the Mediterranean Sea.