water used for agricultural and domestic purposes in deserts in the southwestern United States.Central Asia and South America comes from rivers that originate in glaciers and snow-covered mountains,the report said The glaciers on the Tibetan plateau,for example,may decline by as much as 80 per cent by the end of the century,according to the Intergovermental Panel on Climate Change,a group ofscientists advising the United Nations. "When the glaciers disappear,you are in serious trouble,"said Andrew Warren,one of the report's authors and a professor of geography at University College London. The report warned that renewable water supplies fed to deserts by large rivers are also in danger because of climate change and booming growth.It cited the Rio Grande and Colorado River in North America,the Tigris and Euphrates in Southwestern Asia and the Amu Darya and Indus in Central Asiaas being under threat. The report's authors urge more comprehensive water policies to manage the world's limited supplies more effectively.The report warned that Chad,Iraq,Niger and Syria,for example,could experience scarcity in water supplies by 2050 if nothing is done Mr.Warren also said urgent action is needed to protect wildlife in deserts,noting that increasing wealth in Arab lands has led to convoys ofwater used for agricultural and domestic purposes in deserts in the southwestern United States, Central Asia and South America comes from rivers that originate in glaciers and snow-covered mountains, the report said. The glaciers on the Tibetan plateau, for example, may decline by as much as 80 per cent by the end of the century, according to the Intergovermental Panel on Climate Change, a group of scientists advising the United Nations. “When the glaciers disappear, you are in serious trouble,” said Andrew Warren, one of the report’s authors and a professor of geography at University College London. The report warned that renewable water supplies fed to deserts by large rivers are also in danger because of climate change and booming growth. It cited the Rio Grande and Colorado River in North America, the Tigris and Euphrates in Southwestern Asia and the Amu Darya and Indus in Central Asia as being under threat. The report’s authors urge more comprehensive water policies to manage the world’s limited supplies more effectively. The report warned that Chad, Iraq, Niger and Syria, for example, could experience scarcity in water supplies by 2050 if nothing is done. Mr. Warren also said urgent action is needed to protect wildlife in deserts, noting that increasing wealth in Arab lands has led to convoys of