Nichols' Pelto Uses Satellite Imagery to Track Glaciers

For the last 25 years from July 31st to August 15th, Dr. Mauri Pelto has been in the field researching the retreat of the North Cascade glaciers, the most extensive project of its kind in the United States. The North Cascades span the border between Canada's British Columbia and Washington State.

"My observations make clear that retreat of North Cascade glaciers is rapid and ubiquitous," says Pelto. "All 47 glaciers monitored by the North Cascade Glacier Climate Project are currently undergoing a significant retreat or have disappeared altogether."

Spot Image, a world leader in satellite imagery, has donated five images of the North Cascades from 2006 and 2007 through a not-for-profit collaborative called Planet Action. Planet Action supports projects acting on climate change impacts, causes and solutions.

Pelto used the satellite images to examine the top of the glaciers to determine the amount of snowpack accumulation at the end of the summer. If this area is shrinking markedly, the glacier will disappear. Two observed glaciers, Lewis Glacier and Spider Glacier, no longer exist.

Pelto notes that ongoing temperature rises combined with a reduction in snow accumulation in the North Cascades have resulted in widespread disequilibrium. In fact, in the last 20 years, the total glacier volume has been reduced by 18 to 32 percent. Ongoing thinning of the North Cascade glaciers indicates that they will continue to retreat into the foreseeable future.

Mauri Pelto is a professor of environmental science and Science Program chair at Nichols College in Dudley, Massachusetts.