Much of historic Amsterdam may face destruction in a few decades if its wooden pilings dry up and crumble because of falling river levels caused by the "greenhouse effect," a government-ordered study warns.

The pollution-induced warming of the earth's atmosphere may also cause flooding in Venice, the death of urban greenery in Paris and stifling temperatures in many cities around the Mediterranean, according to Hans Verwaart, a researcher.Verwaart disclosed details of the study by the private International Institute for the Urban Environment on Friday.

He said the project to assess repercussions of the greenhouse effect on 14 mainly European cities was commissioned by the Dutch Environment Ministry and based on recent estimates by the World Meteorological Organization and the United Nations Environment Program.

According to those estimates, average temperatures in Europe will rise by nine degrees Fahrenheit during summer and 5.4 degrees in winter over the next few decades.

Worst-hit by the greenhouse effect would be Mediterranean cities, where stifling temperatures would combine with a drop in average wind speeds, less rain and already massive air pollution, Verwaart said.

The temperature rise would also melt down the huge glaciers covering the mountains of Switzerland, Austria and central Europe, which normally feed major rivers like the Rhine and the Meuse.

When the glaciers are eventually gone, those rivers will dwindle substantially and the water table in much of northwestern Europe will fall, Verwaart predicted.

He added that would cause massive damage to the foundations of the 17th and 18th-century buildings that line the famous canals of this Dutch capital, making their demolition inevitable in many cases.

Historic Amsterdam houses are built on long wooden poles driven deep into the soggy soil until they hit more solid ground. As long as those poles remain covered by a thin layer of water, they are protected from decay.