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South America glacier decline linked with global warming

Temps, not snowfall, drive shrinkage of Peru’s Quelccaya Ice Cap

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The Quelccaya Ice Capis likely shrinking as global temperatures increase. Photo via Edubucher and a Creative Commons share-alike license.

By Summit Voice

FRISCO — Geologists are getting better at unraveling the mysteries of historic glacial episodes, as technology helps understand how the ice sheets respond to climate change.

One recent research project led by scientists from Dartmouth University suggests that temperature is the driving factor in shaping the size of Peru’s Quelccaya Ice Cap. The 17-square mile glacier in the Andes has been shrinking dramatically in the past few decades, making it a global warming symbol.

The findings support the idea that tropical glaciers are rapidly shrinking because of a warming climate — not because of a lack of snowfall. The study results will  help scientists to better understand the natural variability of past and modern climate and to refine models that predict tropical glaciers’ response to future climate change. Continue reading

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Global warming: Andes glacier melt to affect water supplies

New study tracks rapidly accelerating rate of ice decline since 1950s

The Perito Moreno Glacier is one of the largest in Patagonia at 30 kilometers long. The glacier descends from the Southern Patagonian Icefield (image top)—2100 meters elevation (6825 feet) in the Andes Mountains—down into the water and warmer altitudes of Lago Argentino at 180 meters above sea level.

The Perito Moreno Glacier is one of the largest in Patagonia at 30 kilometers long. The glacier descends from the Southern Patagonian Icefield (image top)—2100 meters elevation (6825 feet) in the Andes Mountains—down into the water and warmer altitudes of Lago Argentino at 180 meters above sea level. Satellite image courtesy NASA Earth Observatory.

By Summit Voice

SUMMIT COUNTY — Glaciers in large parts of the Andes have shrunk on average by 30 to 50 percent since the 1970s, and the unprecedented retreat could soon begin to affect water supplies for Andean communities.

Temperatures in the region have warmed by more than 1 degree Fahrenheit in the past few decades, said Antoine Rabatel, a researcher at the Laboratory for Glaciology and Environmental Geophysics in Grenoble, France, and lead author of a recent study on the glaciers in the region.

Globally, glaciers have been retreating at a moderate pace as the planet warmed after the peak of the Little Ice Age, a cold period lasting from the 16th to the mid-19th century. Over the past few decades, however, the rate of melting has increased steeply in the tropical Andes, at a pace not seen for at least the last 300 years. Continue reading

Global warming: Glacial runoff waning in Andes

Alpamayo, in Peru's Cordillera Blanca.

Not much time left to adapt to reduced runoff, scientists warn

By Summit Voice

SUMMIT COUNTY — South American glaciers that provide critical drinking water are retreating faster than expected, and meltwater discharge is also decreasing.

This means that the millions of people in the region who depend on the water for electricity, agriculture and drinking water could soon face serious problems because of reduced water supplies, according to a team of researchers who have closely monitoring the glaciers in the northern Andes. Continue reading

Morning photo: Tierra del Fuego

The southernmost national park in the world

Lago Roca in Tierra del Fuego National Park Argentina.

SUMMIT COUNTY — I’ve taken many more snow photos in the past few days, as Old Man Winter rolls on in Summit County, but I thought I’d give it a break, so I’m featuring Tierra del Fuego National Park, the southernmost park in the world. Leigh and I visited here after a 10-day sea voyage around Antarctica, and the verdant scene was a welcome change from all the ice and snow — sort of like when spring finally arrives here in the high country.

On the shores of Lago Roca, with heavy rainshowers moving in.

Continue reading

Glacial ‘armoring’ helps mountains grow taller

Research in the Andes challenges some of the conventional wisdom about glaciers and mountains.

In cold climates, glacial ice protects mountains from erosion as they’re lifted up by tectonic activity

By Summit Voice

SUMMIT COUNTY — It’s long been known that glaciers help tear down mountains by scouring out rocks and soil. But now, geologists have discovered that in cold climates at low latitudes, glaciers also help protect mountains from erosion, allowing them to grow taller as movements of the Earth’s crust push them up.

That’s why the Andes in the far south are taller than the peaks in the same range farther north, according to researchers from the University of Arizona who studied the range extensively to understand the role of glaciation and climate in mountain-building.

The University of Arizona researchers were surprised by what they found in Patagonia;s Andes Mountains, said Stuart N. Thomson, a research scientist in the University of Arizona department of geosciences. Continue reading

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