Geologists: Collier Glacier is shrinking

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Geologists: Collier Glacier is shrinking Tue Oct 23, 10:57 PM ET

BEND, Ore. - Between the North Sister and Middle Sister in Oregon's Cascade Range, Collier Glacier has advanced and receded for hundreds of thousands of years. But like many glaciers, it is headed in one direction these days: backward.

It is in serious peril, says geologist Ellen Morris Bishop of the Fossil-based Oregon Paleo Lands Institute. "We have basically a really sad picture of Collier Glacier today."

Geologists blame among other things a warming climate, altering the landscape and perhaps the availability of water to high-elevation ecosystems. Collier is shrinking faster than most of the 35 glaciers in the state.

"Now everything is just in a chaotic shrink," Bishop said.

This summer she led a climate change-themed tour of the Central Oregon Cascades, starting from McKenzie Pass and heading south. Volcanic activity built the Cascades, but over eons the glaciers have worn them down.

At the glacier's base is a moraine, or a ridge of rocks, deposited by the slowly moving glacier when it was bigger. Today an empty valley fills the space between the ridge and the glacial edge.

"This was a full valley in 1906," Bishop said. Since then it has retreated more than a mile.

The ice sheet has visibly shrunk since she first visited the glacier in the 1980s, Bishop said.

"We're in trouble," said David Eddleston, of Bend and a participant in the field trip. "It's right there in front of our eyes."

The shrinking of the glacier started about the same time carbon dioxide emissions started rising, Bishop said.

"It's all tied to climate change, said Peter Clark, a geosciences professor at Oregon State University.

http://news.yahoo.com/s/ap/20071024/ap_on_sc/vanishing_glaciers