Andes glaciers are vanishing at unprecedented rates

http://www.msnbc.msn.com/id/50552654/ns/technology_and_science-science/#.UP892WcqmuI

By Stephanie Pappas
updated 1/22/2013

The glaciers of the Andes Mountains have retreated at an unprecedented rate in the past three decades, with more ice lost than at any other time in the last 400 years.

That's according to a new review of research that combines on-the-ground observations with aerial and satellite photos, historical records and dates from cores of ice extracted from the glaciers. The retreat is worse in the Andes than the average glacier loss around the world, the researchers report Tuesday in the journal The Cryosphere.

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The Andes Mountains of South America are home to 99 percent of tropical glaciers ­— permanent rivers of ice at high enough elevations not to be affected by the types of balmy temperatures usually associated with the tropics. But these glaciers are particularly sensitive to climate change, because there is little seasonality in temperatures in the tropics, Rabatel said.

"Glaciers of the tropical Andes react strongly and more rapidly than other glaciers on Earth to any changes in climate conditions," he said.

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Precipitation in the region has not changed, the researchers found, but temperatures have risen nearly 0.2 degrees Fahrenheit (0.1 degrees Celsius) per decade over the last 70 years. That means it's likely atmospheric heat rather than lack of snow is driving the glacier retreat.

The looming loss of the glaciers is a major problem for the people living in arid regions west of the Andes, Rabatel said.

"The supply of water from high-altitude glacierized mountain chains is important for agricultural and domestic consumption, as well as for hydropower," he wrote.