The Aral Sea is a lake located east of the Caspian Sea between Uzbekistan and Kazakhstan in central Asia. This area is part of the Turkestan desert, which is the fourth largest desert in the world; it is produced from a rain shadow effect by Afghanistan’s high mountains to the south. Due to the arid and seasonally hot climate, there is extensive evaporation and limited surface waters. Summer temperatures can reach 60οC (140οF)! The Aral Sea’s water supply is mainly from the Amu Darya and the Syr Darya, which carry snowmelt from mountainous areas. In the early 1960s, the then-Soviet Union diverted the Amu Darya and Syr Darya Rivers for irrigation of one of the driest parts of Asia to produce rice, melons, cereals, and especially cotton. The Soviets wanted cotton or white gold to become a major export. They were successful, and today Uzbekistan is one of the world’s largest exporters of cotton. Unfortunately, this action eliminated any river inflow to the Aral Sea and caused it to disappear almost completely.
In 1960, the Aral Sea was the fourth largest inland water body; only the Caspian Sea, Lake Superior, and Lake Victoria were larger. Since then, it has progressively shrunk due to rivers’ evaporation and lack of recharge. Before 1965, the Aral Sea received 2060 km3 of fresh water per year from rivers, and by the early 1980s, it received none. By 2007, the Aral Sea shrank to about 10% of its original size, and its salinity increased from about 1% dissolved salt to about 10% dissolved salt, which is three times more saline than seawater. These changes caused an enormous environmental impact. A once thriving fishing industry is dead, as are the 24 species of fish that used to live there; the fish could not adapt to the more saline waters. The current shoreline is tens of kilometers from former fishing towns and commercial ports. Large fishing boats lie in the dried-up lakebed of dust and salt. A frustrating part of the river diversion project is that many irrigation canals were poorly built, allowing abundant water to leak or evaporate. An increasing number of dust storms blow salt, pesticides, and herbicides into nearby towns, causing various respiratory illnesses, including tuberculosis.
The wetlands of the two river deltas and their associated ecosystems have disappeared. The regional climate is drier and has greater temperature extremes due to the absence of moisture and moderating influence from the lake. In 2003, some lake restoration work began on the northern part of the Aral Sea, and it provided some relief by raising water levels and reducing salinity somewhat. The southern part of the Aral Sea has seen no relief and remains nearly completely dry. The destruction of the Aral Sea is one of the planet’s biggest environmental disasters caused entirely by humans. Lake Chad in Africa is another example of a massive lake nearly disappearing for the same reasons as the Aral Sea. The Aral Sea and Lake Chad are the most extreme examples of large lakes destroyed by unsustainable diversions of river water. Other lakes that have shrunk significantly due to human water diversions include the Dead Sea in the Middle East, Lake Manchar in Pakistan, and Owens Lake and Mono Lake in California.