The Aral Sea in Central Asia was the fourth-largest lake on the planet in 1960. By 2007 it had shrunk to 10 percent of its original size. Widespread, wasteful irrigation of the deserts along the Amu and Syr rivers, which feed the Aral, cut the freshwater inflow to a trickle. Nevertheless, a dam built in 2005 has helped the northernmost lake expand quickly and drop substantially in salinity.