Over the last 30 years the Aral Sea has shrunk to a fraction of its former size. The central Asian republics of Kazakhstan, Uzbekistan, Kyrgystan, Tajikistan and Turkmenistan depend upon the sea for survival.

By the year 2015 the Aral Sea could totally disappear.

The problems began when the former Soviet Union made Kazakhstan its main producer of cotton, a plant that needs a great deal of water.

BBC analyst Malcom Haslitt explains to World Service radio what went wrong (2'24')

Local people were concerned about the damage to the environment caused by growing just one crop. The Soviet Union promised to divert rivers thousands of miles from Siberia to feed the receding sea, but the plans were never realised.

The International Federation of the Red Cross and Red Crescent has called for urgent help. It is organising a conference this week to try to save the region.

Red Cross spokesman Martin Faller said: "We think it is very important to help the people living in the Aral Sea area. They are all affected by environmental degradation. The Red Cross wants to help people to cope with their daily lives."

The water was diverted to irrigate cotton fields

BBC correspondent Louise Hidalgo in Kazakhstan says that the most amazing thing about the disaster is that it is no accident.

"The Soviet planners who fatally tapped the rivers, which fed the seas to irrigate central Asia's vast cotton fields, expected it dry up. They either did not realise the consequences the Aral's disappearance would bring or they simply did not care."

Since 1968 the level of the Aral Sea has dropped by more than 16m and in its southern half it has shrunk by 150km. The two main fishing ports are now dry, stranded tens of kilometres from the water.

Salt and dust now blow across the region

The climate too has changed. Salt sand and dust from the exposed mud beds blows across the region, wreaking damage on the people and the agriculture. Pesticides and fertilisers, which used to feed the cotton fields, have found their way into water and irrigation channels, poisoning food and drinking water.

The BBC correspondent said: "The human cost of this disaster is high and the areas around the Aral Sea now have the highest death and infant mortality rates out of all the former Soviet Union. Almost all pregnant women are anaemic and the catalogue of health problems goes on."