Using new and more accurate methods of analysis, experts say glaciers in the US, western Europe, Africa, Russia, China and New Zealand are disappearing at an alarming rate.

The only anomaly is in Norway where heavy rain and snowfall during the 1980s and 90s mean ice caps are growing.

Researchers with the University of Colorado collected data on just a few hundred of the 200,000 glaciers around the world. Yet they claim the trend is clear.

Mountain ice in regions such as the Alps, the Pyrenees and the Rockies is vanishing fast while sea levels rise.

The Chamonix glacier on Mont Blanc in the Alps, where warming is taking effect

Although glaciers outside Antarctica and Greenland constitute only about 6% of the world's ice mass, their water is recycled more quickly and contributes more to sea level rise than do the polar ice sheets.

A leading scientist involved in the research said he was certain the pattern was a result of man-made global warming.

The investigation was carried out by a team at the university's Institute of Arctic and Alpine Research.

Thickness and volume

Using algorithms - mathematical instructions for solving problems - it was able to define the relationships of variable glacier characteristics. The method allowed scientists to estimate sizes, thickness and volume distribution of glaciers more accurately than before.

Reporting the findings to a meeting of the American Geophysical Union in Boston, Massachusetts, Professor Mark Meier, said: "The disappearance of glacier ice is more pronounced than we previously had thought."

He warned there had been a "significant decrease" in the area and volume of glaciers over the last century, especially at "mid and low latitudes."

Rivers rise

The depletion of mid-latitude glaciers was causing some rivers to rise significantly.

"The rate of warming is unprecedented in the last 600 years and the retreat of glaciers is probably unprecedented too, although we do not have the figures to prove it," he said.

"But I am convinced there is a detectable human influence in the pattern of climate change we are seeing."

Among the team's findings were that:

• The number of glaciers in Spain had dropped from 27 to 13 since 1980.

• Both the Alps and the Caucasus Mountains, in Russia, had lost about half their glacial ice in the last 100 years.

• In New Zealand glaciers had shrunk by about 26% since 1890.

• In eastern Africa, the largest glacier on Mount Kenya had lost 92% of its mass in the past 100 years while those on Mount Kilimanjaro receded by 73% in the same time period.

• The thousands of glaciers in the Tien Shan mountain range bordering China and Russia had lost 22% of their ice volume in just the past 40 years.

• Preliminary calculations indicated that Montana's Glacier National Park in the United States will have no glaciers left within 100 years, and perhaps sooner.