Study of melting glaciers reveals that high altitudes are more affected by climate change

Eric Newhouse in the Great Falls Tribune (Montana): The swift meltdown of the glaciers in Glacier National Park has led scientists to believe mountains are more susceptible to global warming than the lowlands around them. "During the past 15 years, there has been a faster rate of temperature increase for mountains than for lower elevations," said U.S. Geological Survey ecologist Dan Fagre in West Glacier.

"For the Glacier Park area, that annual increase is almost 2 degrees Fahrenheit ... almost as much as occurred over a century for low elevation sites," he said. "This helps explain why we are seeing fairly dramatic reductions in glaciers and changes to our annual snowpacks."

The evidence is striking, as anyone can see by looking at a before-and-after photographic comparison of the park's glaciers on a Web site run by the U.S. Geological Survey. Today, Glacier has only 25 of the 150 glaciers that were large enough to name in 1850.

…But it's not just Montana. "Across the globe, the rates of temperature increase in the mountains have been greater than in the adjoining lowlands," Fagre said. Now geologists are seeking an explanation for this scientific puzzle.

One theory is that global warming leads to greater evaporation, more moisture in the system and greater cloud cover. "Under clear skies, particularly at night, the mountains radiate heat, but under a cloud cover they retain that heat," Fagre said. That cloud cover may also generate additional heat, he said....

Grinnell Glacier in Glacier National Park, with arrows showing the former extent of the retreating ice. US Geological Survey