wilderness lecture series

Climate Change Impacts More Than Glacier’s Glaciers

By Peter Metcalf, 2-13-08

	A mountain goat along the Hidden Lake Overlook trail in Glacier National Park. Photo by David Restivo, courtesy of Glacier National Park.

Thanks to a changing climate, not only may Glacier National Park need a new name, but eventually a new mascot. The park’s iconic mountain goats are already feeling the impacts of climate change, said Dan Fagre, a research ecologist for the U.S. Geological Survey’s Northern Rocky Mountain Science Center in Glacier National Park.

“This is ironic because the mountain goat is the icon of Glacier National Park,” Fagre told a mixed crowd of students and community members at the University of Montana Tuesday night.

Fagre lectured on the “Cascading Climate Change Impacts on the Crown of the Continent Ecosystem,” as part of the University of Montana’s 2008 Wilderness Issues Lecture Series.

The predicament for mountain goats is the conversion of important sub-alpine meadow habitat to trees. Lower winter snow accumulation combined with earlier spring melt off has allowed young sub-alpine fir trees to survive the winter and colonize formerly open meadows. The new stands of trees reduce available forage, provide shelter for predators and fragment habitat. To date, Glacier has lost about four percent of its alpine zones to trees.

Mountain goats are not the only species impacted by a changing climate. Rising temperatures and altered precipitation patterns will provide some species opportunity expand their range, while others will shrink or die out altogether.

	Courtesy of the U.S. Geological Survey, www.nrmsc.usgs.gov/repeatphoto/gg_overlook.htm

“There are winners and losers” to climate change, Fagre said, “but there is definitely fundamental change.”

The difficulty in predicting precisely how a species will be impacted by climate change is a lack of certainty to the rate of change and the amount of change a species can tolerate, Fagre said. All species can tolerate incremental change, but at some point they cross a threshold from which there is no recovery.

One thing that has certainly crossed a threshold is the park’s glaciers.

“There is no partisan politics involved with glaciers,” Fagre said to laughter from the crowd. “They can’t vote. They just sit there and melt.”

And they are melting faster every year. Grinnel Glacier in the Many Glacier region has lost 90 percent of its mass since it was first documented in the late 1800s. The glacier continues to shrink at nine percent a year, the ice turning into a pale green lake.

“Grinnel Glacier is basically melting into its own puddle,” Fagre said. He predicts the glacier will disappear within 20 years.

The same is true of the rest of park's remaining 20 to 24 glaciers. Photographs taken from the same vantage point over the decades provide a stark record of the glaciers march toward extinction. In a photograph from 1932, four hikers appear as tiny figures in front of the Boulder Glacier’s massive wall of ice. In 1988, exposed rock and new vegetation cover the hillside revealed by the now extinct glacier.

Glaciers that have been on the landscape for at least 8000 years will be gone in about two decades, Fagre said.

“One of the recurring themes of climate change is things are happening faster than we thought."

The decline of the glaciers leads to a cascade of affects on the rest of the park's ecosystem. Many of glacier’s plant communities rely in late summer on water released by glaciers. Declines in frigid glacial melt water raises stream temperatures which in turn changes the stream’s composition of microorganisms. These changes hit native bull trout hard, eliminating habitat for these temperature sensitive fish and extirpating food sources that cannot tolerate the warmer water.

Like the rest of the Northern Hemisphere, Glacier is experiencing rising temperatures and declines in winter snowfall. Snowpack across the northwest is about 60 percent less on April 1st than historical norms.

“We have spring a month earlier than we used to,” Fagre said.

These temperature and snowfall changes mean more winter precipitation falls as rain, increasing the likelihood for unusual weather events, such as the November 2006 flood that wiped out portions of the east side of Going-to-the-Sun highway. The decline in winter snow also means fewer avalanches to scour away trees and keep the avalanche shoots open that provide essential forage for grizzly bears and a host of other species. These trends to warmer temperatures and earlier springs also increase the frequency and scale of wildfires in the ecosystem.

According to Fagre, the thresholds we’ve crossed in altering the planet’s climate are irreversible. At least in the near term. People need to not only work to keep from crossing new thresholds of climate change that will lead to a cascade of other consequences, but need to prepare to live on an altered planet, he said.

“We have to adapt to the new regime."

For the speaker schedule for this year's Wilderness Issues Lecture Series at the University of Montana in Missoula, click here.

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