Aral Sea: nothing new under the Sun

Image of the month - November 2003

Aral Sea as seen by Meris onboard Envisat, on July 9, 2003 (Credits Esa)

The catastrophic shrinking of the Aral Sea level is continuing. Since large amounts of water are diverted from its tributaries to irrigate cotton fields, this inland sea of nearly fresh water has lost most of its volume and surface area since 1960. The recession is estimated as nearly half of its volume over the last fifteen years.
In 1989, the Sea split into two basins, the Great and the Small Aral. In one or two years time, the Great Aral will in turn split up. The basin already has a high degree of salinity (80 g/l, i.e. almost that of the Dead Sea ), and its ecosystem is gradually weakening. It will soon only support the very few species that can live in such a salty environment. While the situation appears to be desperate for the Great Aral (at least as long as irrigation continues, ), the Small Aral can still be stabilized by re-building the dam that broke in 1999 (just after the Image of the Month we published on this subject, in July 1999)
This drying-up of the Aral Sea is not the first in History. Around the 7th century, and later during the Middle Ages (again mostly due to irrigation), the Aral Sea had already dried up. Ecological and sanitary problems are acute in the region, as the old sea bed is covered with accumulated salts, which the wind carries away and deposits over thousands of square kilometres of cultivated land. Pesticides and fertilizers have also found their way into the water and irrigation channels, poisoning food and drinking water which affects the health of about five million people.

Variations of the Great Aral (left) and Small Aral (right) level, measured by Topex/Poseidon and Jason-1. While the Small Aral's level is nearly stable, the Great Aral is drying up fast. (Credits Legos)

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