In order to predict the future, scientists around the world are trying to predict the past. And studies of a Yukon glacier might help them get it right.

Predictions of future climate change are based on computer models, but there is no way to check the accuracy of the models without waiting a hundred years to see what happens, says Garry Clarke, specialist in glaciology at the University of British Columbia.

So, instead of looking forward, scientists are looking back and trying to develop a model that would have predicted a known climate event in the past, the last ice age. If the model can predict accurately what did happen, then chances are it can predict what will happen.

"We know a lot about the last ice age, even though there was no direct observation," says Clarke. "The challenge is to get the computer models to recreate that."

Clarke's research group is contributing its knowledge of glaciers and ice sheets to the international effort.

"The ice sheets are part of the climate system too," Clarke explains. They contribute fresh water to the world's oceans and form huge white areas that reflect back solar radiation. They also have an effect on local temperature and weather patterns.

Since 1969, Clarke and his colleagues have been studying the way the ice flows and moves in Trapridge Glacier in the St. Elias Mountains of the southwest Yukon. For the past five years, they have been co-operating in the development of climate modeling systems.

"Our contribution is to describe ice sheet behavior," Clarke says. His group is part of an international effort that includes the European Ice Sheet Modeling Initiative and an American group studying the ice sheets of Antarctica and Greenland.

Studying glaciers is not easy. They're large, remote and, generally, not very hospitable. Over the years, Clarke's research group has had to develop specialized instruments to measure and record the movements of the massive bodies of ice. Those instruments are now used in glacier study around the world.

Clarke and his group start their season's work at the Arctic Institute base camp near Burwash Landing. The Arctic Institute has been very supportive over the years, Clarke says.

"That base camp is just the best thing that ever happened to Yukon science."

From Burwash Landing they ferry their supplies by helicopter to a camp beside the glacier at an altitude of about 2800 metres. The setting is beautiful and the temperatures, in July, are much like spring skiing conditions, Clarke says.

"As far as real hardship goes, there isn't much of that. We've got a really comfortable camp set up."

Glacier research is tougher on instruments than people. The scientists use a hot-water drill to punch holes through 75 metres of ice to the ground beneath the glacier. There they set sensors that record the movement of the glacier grinding over the rock base and feed the information back to computers on the surface.

"It isn't too kind to the sensors," Clarke says. "Things get kind of crunched. Also the wires break because the glacier keeps moving further."

On top of the glacier, survey poles are set into the ice to measure the surface flow. Keeping them positioned properly, through snow, wind, and sudden melts, is "a big maintenance challenge," the glaciologist says.

Clarke and his team of researchers will spend about a month at Trapridge Glacier this summer. Their first job is to collect information the automated instruments have been gathering all winter.

"You get very big disappointments sometimes," says Clarke. One year heavy snow covered the solar panels that power the instruments and everything stopped operating in March. Another year, warm spring sunshine melted many of the survey poles and data collection devices right out of the glacier.

Once the winter's data is collected, the team will repair and replace existing instruments and set up new monitoring systems. Then they will return to Vancouver, leaving behind an instrument array that they hope will continue to collect data for the next 11 months, contributing knowledge about the earth's past and its future.

For more information about Yukon research, contact Environment Canada in Whitehorse or the Yukon Science Institute.