North America

The North American glaciers located along the Rocky Mountains in the United States and Canada and the Pacific Coast Ranges from northern California to Alaska are nearly all in a state of active retreat. Since 1980, the rate of retreat has increased each decade.

In the North Cascade Mountains alone (part of the Pacific Coast Ranges), there are more than 700 glaciers; the area extends from central Washington to the Canadian border. These glaciers store a tremendous amount of water, equal to all the lakes and reservoirs in Washington State alone. These glaciers are a critical resource for inhabitants of the area because they provide water each summer. Unfortunately, since the mid-1980s, the North Cascade glaciers have lost an average of 41 feet (12.5 m) in thickness and nearly a quarter to half of their volume.

Of the 47 glaciers in the North Cascades that are being monitored, all are receding. Even worse, Lewis Glacier, Spider Glacier, Milk Lake Glacier, and David Glacier, have completely melted and disappeared.

In Glacier National Park in Montana, glaciers have also been disappearing rapidly. In 1850, the park was a showcase of 150 unique glaciers. Today, it has only 26 left. In fact, more than two-thirds of its glaciers and about 75 percent of its area covered by glaciers have completely disappeared. The National Park Service and the USGS have mapped the area of each glacier in the park for decades, and in 1997, the USGS began the Repeat Photography Project to monitor and document the physical retreat of the glaciers in the park. Glaciers throughout the park are retreating and being documented. The larger glaciers are only about one-third of their former size.

Dr. Daniel Fagre, a federal research scientist based at Glacier National Park, has stated that "because of global warming, . . . estimates [are] that all the glaciers in the park will be gone by the year 2030." He explains, "The glaciers respond to global warming by having less snow in the winter and then they start melting earlier in the spring. The summers, of course, are always a period when they melt but these are now longer. 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. So I don't think that we'll see much of a change in the next few decades."

In the Canadian Rockies, an outlet glacier called the Athabasca has retreated 4,921 feet (1,500 m) since the late 1800s. Some glaciers in Canada stopped retreating and had brief periods of increase for a few years but then switched back into a long-term trend of recessions.

There are thousands of glaciers in Alaska. Columbia Glacier, near Valdez in Prince William Sound, has retreated 9.3 miles (15 km) during the past 25 years. Mendenhall Glacier near Juneau, Alaska, has retreated 1,902 feet (580 m). The only glacier that has shown a positive trend is Taku Glacier.

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