By Tim Hirsch BBC Environment correspondent in Kyoto

The disaster has hit the Marsh Arabs who rely on the waterways

Latest satellite images show that less than 7% of the Mesopotamian marshes now remain intact.

This is the area where the rivers Tigris and Euphrates join, and is thought by some to be the original site of the Garden of Eden.

In 2000, it was estimated that 90% of the natural wetland had disappeared, through a combination of drainage works and dams upstream which restrict the flow of the rivers.

But the latest images analysed by the UN Environment Programme (Unep) show that yet more of remaining marshland straddling the border with Iran has dried out.

Scientists fear that it could disappear completely within three to five years without urgent action.

Large areas of once thriving wetland habitats have now been reduced to barren wasteland, creating huge problems for local people as well as wildlife.

Among the threatened species are the Sacred Ibis and African Darter, which are said to be holding on at a knife's edge.

And the drying of the region has caused enormous problems for the Marsh Arabs, whose culture is closely linked with the wetland environment.

Indeed, Saddam Hussein was accused of deliberately draining the marshes as a tool of oppression against the marsh people, who opposed his regime, and to clear the way for his tanks to advance during the Iran-Iraq war.

But the problem has an international dimension, as dams upstream in Turkey and Syria have reduced the flow of the rivers into Iraq.

It is feared that new Turkish dams planned for the River Tigris, including the controversial Ilusu project, could make the situation worse.

Unep's executive director Klaus Toepfer revealed the new information on World Water Day (22 March), here at the World Water Forum.

He said: "As we mark World Water Day 2003, we are reminded of the dramatic destruction of the Mesopotamian marshlands over the past decade, a major environmental catastrophe underscoring the great pressures facing freshwater ecosystems across the globe."

Dr Toepfer added that after the present conflict, Unep would be working with international partners including the United States on the revitalisation of the marshes - he said that must include co-operation between all the countries in the Tigris-Euphrates basin on management of fresh water in the region.