Tuesday, 2 October 2012

The disappearance of the Aral Sea

The creeping disappearance of the Aral Sea counts as one of the greatest man-made environmental disasters of the 20th century. In the years between 1960 and 2000 alone, the area enclosed by the Aral Sea fell by more than half, from 68,000 km² to some 32,000 km².

The disappearance of the Aral Sea in central Asia was caused primarily by the diversion of the inflowing Amu Dar’ya and Syr Dar’ya rivers to provide irrigation water for local croplands. These diversions dramatically reduced the river inflows, causing the Aral Sea to shrink by more than 50%, to lose two-thirds of its volume, and to greatly increase its salinity. At the current rate of decline, the Aral Sea has the potential to disappear completely by 2020.

In 1963, the surface of the Aral Sea measured 66,100 km2, with an average depth of 16 m and a maximum depth of 68 m. The salt content was 1%.

By 1987, 27,000 km2 of former sea bottom of the Aral Sea had become dry land; about 60% volume had been lost, its depth had declined by 14 m, and its salt concentration had doubled.

The former fishing town of Moynaq, where not long ago thousands of people still gained their livelihoods from fishing and fish processing, is today a desert town in which the rusting hulks of ships lie stranded more than 100 kilometres distant from the Aral Sea.

Today, about 200,000 tonnes of salt and sand are carried by the wind from the Aral Sea region every day, and dumped within a 300 km radius. The salt pollution is decreasing the available agriculture area, destroying pastures, and creating a shortage of forage for domestic animals. The number of domestic animals in the region has become so low that the government has issued a decree to reduce the slaughter of animals for food.

Fishing in the Aral Sea has ceased completely, while shipping and other water-related activities have declined; the associated economic changes have taken a heavy toll on agricultural production.

The quality of drinking water has continued to decline due to increasing salinity, bacteriological contamination, and the presence of pesticides and heavy metals.