Lake Chad, once one of the world’s largest water bodies, could disappear in 20 years due to climate change and population pressures, resulting in a humanitarian disaster in central Africa, the United Nations Food and Agriculture Organization (FAO) has warned. The lake – surrounded by Cameroon, Chad, Niger and Nigeria – has shrunk by 90 per cent, going from 25,000 square kilometers in 1963 to less than 1,500 square kilometers in 2001.