Danger in Degrees, part 1
Earlier this year Allen Best, the Colorado writer who compiles the Mountain News, wrote a seven-part series for the Aspen Times on climate change and the mountains. Part 1 of the series appears here; a second part will be featured next week in Pique.
Hiking along the Continental Divide north of Georgetown, Colorado during late summer three years ago, Ed Knapp noticed something awry. Several feet below the lip of a withering field of ice and snow was a skull with down-turning horns. It was, he quickly concluded, the skull of a bison.
Bison skulls in the Rocky Mountains are by no means rare, even if none had ever been found quite so high, at nearly 13,000 feet in elevation. The surprise was the rapid retreat of ice from which the bison skull emerged. When Knapp, a 60-year-old building contractor from metropolitan Denver, began hiking the Continental Divide near Jones Pass in the 1970s, the permanent snowfield had been 200 metres long. A year after it yielded the skull, it vanished altogether.
Make no mistake, the climate is shifting across North America and the world. The 10 warmest years since record-taking began have occurred since 1983. Mountain glaciers have been reduced by about half. Sea levels are up 6 to 10 inches. Severe heat waves have become more frequent.
In the mountains, evidence of warming is found at every turn. Winter nights are less frigid. Spring runoff comes earlier. The frost-free season has expanded — in Aspen by more than three weeks, according to recordings kept since 1949 at the town’s water plant.
The David Suzuki Foundation, which launched the Melting Mountains awareness program in February 2003, in co-operation with the Alpine Club of Canada and Mountain Equipment Co-op, calls mountains nature’s water towers. The Suzuki Foundation says that in the Canadian Rockies, late summer river flows have decreased due to the drastic reduction in glacial cover over the past century.
But do not make too much of local or even regional weather, says Susan Salomon, a scientists from Boulder, Colorado renowned for her pivotal role in research about the ozone hole over Antarctica. “Climate varies in your backyard much more than it does in the global mean,” she says. “We have to be very careful in trying to attribute local variations to global warming.”
That said, there’s no question the globe is warming. Some change may well be due to natural climate change, but the broader evidence of climatic change is beginning to add up. Nearly all scientists now agree that people — primarily through the burning of coal, petroleum and other fossil fuels that create greenhouse gases — are the main reason.