Washington, September 1 : A long-term study of key glaciers in western North America has shown that glacial shrinkage is rapid and accelerating, and that it is a result of climate change.

William Shilts, a geologist at the University of Illinois, spent nearly two decades studying glaciers on Bylot Island, an uninhabited island about 300 miles southwest of Thule, Greenland.

Working with his students and other geologists, he has chronicled the decline of several Bylot Island glaciers.

The researcher says that photos of the island from the 1940s to the present offer a vivid picture of the changing glaciers, and the forces that shape their retreat.

“I started working in the late 1970s on Bylot Island, which is about the size of New Jersey. Bylot Island is like a miniature North America. It has a very old crystalline rock core that’s covered with ice and glaciers, and it’s surrounded by younger rocks,” said Shilts, the executive director of the Institute of Natural Resource Sustainability at Illinois.

“As time went on it became very evident that the glaciers on Bylot Island were, for the most part, retreating, shrinking, melting faster than ice could be produced. For whatever reason, the summer melting was exceeding the winter snowfall,” he added.

The photos that Shilts clicked in the 1980s and 1990s show a steady and rapid decline in the extent of several glaciers: Stagnation Glacier, covered in a layer of rock and debris, has shrunk considerably since 1948.

The researcher says that nearby Fountain Glacier seems more stable, but the outwash plain below it, a zone always coated in a thick layer of ice, even throughout the summer, was completely dry in the summer of 2008.

Shilts has revealed that Aktineq Glacier has shrunk back about a kilometre since 1948.

He also says that most of the other glaciers on Bylot Island, and on nearby Baffin Island, also appear to be melting away.

“And that is that the glaciers that are now on Bylot Island were as far advanced in the 1940s as they have been in the last 55,000 years. And now they are retreating,” Shilts said.

“My interpretation of what I saw on Bylot Island is that we’re in another cycle of glacial retreat. Whether that cycle is primarily driven by human emissions of carbon dioxide in the atmosphere creating a warming trend, or whether it’s driven by natural cycles, which relate to our orbit around the sun, sunspot activity or various things in the earth’s atmosphere in general, I can’t say.

“My personal opinion is that this is a combination of both factors. There’s a normal cycle here – we’re coming out of the ‘Little Ice Age,’ and have been for some time. At the same time, the Industrial Revolution has begun to load the atmosphere with carbon dioxide among other things. There’s a human effect, and there’s a natural effect, and sorting out those two is very difficult,” Shilts added. (ANI)