Question

What are the causes of the Aral Sea’s drastic reduction in size over the past 50 years? What are the effects of its depletion?

Answer 1

In the 1960s, the Soviet Union undertook a major water diversion project on the arid plains of Kazakhstan, Uzbekistan, and Turkmenistan. The region’s two major rivers, fed by snowmelt and precipitation in faraway mountains, were used to transform the desert into farms for cotton and other crops. Before the project, the Syr Darya and the Amu Darya rivers flowed down from the mountains, cut northwest through the Kyzylkum Desert, and finally pooled together in the lowest part of the basin. The lake they made, the Aral Sea, was once the fourth largest in the world. By 2001, the connection had severed, causing all water to halt its transportation to the body of water. A factor that accelerated the evaporation is that the salinization of the lake has lead to vertical stratification. Stratification is characterized by a rapid change in water temperature and salinity level at a given horizontal or vertical region. Under this condition, the surface of the lake has a much lower salt concentration than the bottom of the lake, and thus heats up faster than if the salt concentration was distributed evenly.