West Africa's coastal area is critical to the region, home to a third of its people and the source of about half of its GDP. Because most of it is composed of mangroves and sand formations, the area's coastline is also highly vulnerable to erosion caused by coastal currents and storm surges. Erosion is evident from Mauritania to Gabon-and the rates of erosion are increasing. Around the port of Lome, for example, Togo's coastline is estimated to have receded by as much as 12-15 meters a year