It could take just five such summers in the coming decades to "bring about this scenario of widely deglaciated Alps," they say.
The study notes that 90 percent of glaciers are vulnerable, being less than four-tenths of a square mile (one square kilometer) in area.
Increases in global temperature predicted by the IPCC could lead to the "complete deglaciation of entire mountain ranges," the researchers add.
"Only rather small glacier remnants would persist in a few regions with the highest mountain peaks."
Lead study author Michael Zemp, a glaciologist, said, "Glacier change is happening very fast."
"The mean thickness of Alpine glaciers is about 20 to 30 meters [66 to 98 feet]," he added.
"In the summer of 2003 we lost about 2.5 meters [8.2 feet] of glacial thickness on average over the entire area, so you can calculate how many summers of this kind we can afford."
Zemp says tourism in the region is likely to suffer as a result.
"People are traveling to the white Alps, and I believe they will not go to the black mountains," he said.
Ski resorts that rely on glaciers to provide skiing in the summer and before the first snowfalls of winter are particularly at risk, he adds.
Some ski resort operators are so concerned about their frozen assets that they have taken to covering them in a range of textiles to protect them from the glare of the sun.
For instance, Austria's Stubai Glacier was draped in nearly 25 acres (10 hectares) of white covering last summer.
Such measures won't be enough save Alpine glaciers in the long term, Zemp says.
"It might help in very specific locations but it's much too expensive to cover whole glaciers. And while this protects against radiation [from the sun], the thing that is changing is temperature," he said.
"There's no way to protect entire glaciers or the deglaciation of an entire country," he added.
Floods and Rockfalls
Zemp also warns that fast-melting glaciers could leave Alpine settlements vulnerable to devastating floods and rockfalls.
As glaciers retreat, he says, "All the debris that was pressed against the rock wall by the glacier starts coming down."
Meanwhile glacial lakes formed by accumulated meltwater may suddenly burst on the valleys below.
The team says the situation in the European Alps is mirrored in mountain ranges around the globe.
"This trend of glacier-shrinking is a worldwide phenomenon," Zemp said.
In the Himalaya, for example, the Khumbu Glacier on Mount Everest has retreated more than three miles (five kilometers) from the point where Edmund Hillary and Tenzing Norgay set out to climb the world's highest peak in 1953.
Nepalese researchers recently set up automatic weather stations in the region to record how climate change is affecting the country's glaciers.
(Read "Himalaya Ice-Melt Threat Monitored in Nepal" [March 2006].)
Zemp admits, however, that the global picture can be confusing.
In some regions glaciers have actually advanced in the past decade, in response to short-term changes in weather patterns.
For example, on the west coasts of New Zealand and Norway, increased winter snowfall has compensated for a rise in temperatures.
The European Alps may likewise benefit in future. But the new study shows that, to offset a 1.8-degree-Fahrenheit (1-degree-Celsius) rise in summer temperatures, precipitation would need to increase by 25 percent in the region.
The University of Zurich team says the shrinking of mountain glaciers is "the most obvious indication in nature of fast, if not accelerating, climate change on a worldwide scale."
"Temperature rise isn't something you can see. But a glacier melting is something everybody can see," Zemp added.
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