That Alpine glaciers are melting fast is old news to European ski resorts, which are watching the multimillion-dollar winter tourism trade trickle away.
The Andermatt resort in Switzerland made headlines in 2005 when it decided to wrap part of its glacier in a high-tech blanket designed to stop the melting.
Global warming fueled by greenhouse gas emissions appears to be the main cause of the melting glaciers, according to the University of Innsbruck's Psenner (see our global warming fast facts). Studies of prehistoric climate, though, suggest that Alpine glaciers nearly disappeared at least once in the past 10,000 years.
Thompson said past glacier meltdowns were likely related to changes in characteristics of Earth's orbit, which occur on cycles that last between about 20,000 and 100,000 years. Today's changes have occurred in the last hundred years.
The melting trend "is consistent with projections that have been made based on warming occurring due to increases in greenhouse gas in our atmosphere," Thompson said.
Psenner noted that the past glacial melting occurred when atmospheric levels of the greenhouse gas carbon dioxide (CO2) were 280 parts per million. Today's carbon dioxide levels are approaching 385 parts per million.
"Even if we could manage to keep the CO2 level constant at 385 parts per million—mission: impossible—the glaciers will disappear within one generation," he said.
"So the disappearance of the glaciers is more a factor of time than of increasing temperature: They will be gone even if we keep the climate of today."
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