A panel meeting in France this week plans to discuss concerns that human-caused warming of the climate is why the glaciers in Glacier National Park are melting.
CBS News correspondent Stephan Kaufman reports one proposal to be discussed at the World Heritage and Climate Change meeting in Paris this week is a plan to designate Montana's Glacier National Park as a "world heritage site in danger" due to global warming.
A dozen organizations last month filed a petition asking the United Nations to declare Glacier in Montana and the adjacent Waterton Lakes National Park in Canada endangered, because of glacial retreat and its effect on the environment of the parks. Together they are known as Waterton-Glacier International Peace Park, and are covered by a 1995 treaty as a UNESCO World Heritage Site.
Dr. Daniel Fagre, a federal research scientist based at Glacier National Park in Montana, says that in 1850, the park had 150 glaciers. Today, because of global warming, there are only 27 left, with estimates that all the glaciers in the park will be gone by the year 2030.
"The glaciers respond [to global warming] by having less snow in the winter and then they start melting earlier in the spring," he explains. "The summers, of course, are always a period when they melt but these are now longer."
The glacier situation is unlikely to improve anytime soon, says Fagre.
"It would take a pretty substantial climate change to bring our glaciers back. We would have to get a lot of moisture and it would have to get cooler," says Fagre. "So I don't think that we'll see much of a change in the next few decades."
"The trees are responding, the soil carbon, the streams, all of these are responding [to the climate change], but it's harder to measure those and hard to see them than it is the glaciers," says Fagre.
Glaciers, he says, are important "in nurturing some our streams in late summer and there're a lot of aquatic organisms that live in those streams, so we'll be using this as an instructive example and studying it so we understand how eco-systems in general respond to climate change."
The mean summer temperature at Glacier Park has risen by about 3 degrees Fahrenheit over the past century, according to the USGS.
Declaring Waterton-Glacier in danger would require the World Heritage Committee to identify ways of mitigating effects of climate change, said Erica Thorson, an Oregon law professor who wrote the petition.
Also up for discussion at this week's meeting at the headquarters of the U.N. Educational, Scientific and Cultural Organization are reports of environmental degradation at Nepal's Sagarmatha National Park, which includes Mount Everest; Huarascan National Park in Peru; Great Barrier Reef in Australia; and the Belize Barrier Reef Reserve System in Central America.
© 2006 CBS Interactive Inc. All Rights Reserved. This material may not be published, broadcast, rewritten, or redistributed. The Associated Press contributed to this report.