Aral Sea

Inland sea divided between Kazakhstan and Uzbekistan, the world's fourth-largest lake; former area 62,000 sq km/24,000 sq mi, but decreasing. Since the 1960s water from its tributaries, the Amu Darya and Syr Darya, has been diverted for irrigation and city use, and the sea is disappearing, with long-term consequences for the climate. It has also become increasingly saline, with the salinity having tripled since the mid-20th century.

The sea was known in ancient times as the Oxianus Lacus (Lake of Oxus) as the Oxus river, now known as the Amu Darya, is the principal river flowing into this sea. Between 1960 and 1990 the water level dropped 13 m/40 ft, reducing the lake to two-thirds of its original area. Between 1989 and 1991 alone, its area was cut by nearly half; the sea has now become two separate water areas: the Large and Small Aral seas covering (in 1991) 31,000 sq km/11,970 sq mi and 2,800 sq km/1,080 sq mi, respectively. The shrinkage is caused by expanded irrigation schemes and climate change: hotter, drier summers and longer, colder winters and the number of days without rain per year increased from 30 in the 1950s to 120 in 1993. The 24 native fish species in the lake have been reduced to four. Dust storms are common, and winds drop 43 million tonnes of salt a year on the surrounding cropland.

In 1994 the governments of five central Asian states pledged 1% of their budgets to help save the Aral Sea and improve the health of those living nearby.

The highest rate of anaemia in the world is found among women living in Uzbekistan on the shores of the Aral Sea. In 1999, 98% of women were anaemic in the town of Nukus. A local doctor who has been documenting the area's declining health 1984–99, estimates that anaemia incidence has increased almost sixfold during this period, birth defects and liver cancer have increased fivefold and kidney disease is 20 times as common. Health problems are linked to the dust levels from the dried up seabed. Dust contains salts and organophosphate pesticide residues and pollutes air and drinking water.