Canada Ice Core to Yield Clues on Global Warming

The Geological Survey of Canada said on Thursday its ice-core expedition will see scientists climb Mount Logan -- Canada's highest peak at 5,959 meters (19,550 feet) and the second highest in North America -- in the isolated St. Elias ice fields that straddle the border of the Yukon Territory and Alaska.

"What we're going for on this expedition is the big story, the long story, the 10,000-year record," said Don Lemmen, chief of environmental geology at Natural Resources Canada.

Two Canadian scientists will battle snow storms and bone-chilling temperatures to scale the snow-covered peak -- also the world's largest massif -- in May and June.

They will drill into it sideways near its top until they reach bedrock to pull out a tube of ice measuring 225 meters (738 ft) -- the longest sample yet taken from Logan and the first time such an extensive study will be conducted on a geographical feature located so near the Pacific Ocean.

"The real issue that we're trying to address is: how does the climate vary naturally, and what influence human beings have now and into the future?" Lemmen said.

The tube will be cut into one-meter slices that will be cached on the frozen mountain until next spring, when they will be brought down and carried by refrigerated trucks and airplanes to laboratories in Ottawa.

Scientists from the United States, Japan and Sweden are participating in the study and will look at snow samples as well as pollen, aerosols and volcanic ash deposited onto the massif from the atmosphere over thousands of years.

Climate change, in particular global warming, has fast become a huge environmental issue as worries grow over the effects of chemicals used by humans on the earth's atmosphere.

Mount Logan constitutes the perfect ice museum because its distance from human habitation has saved it from exposure to civilization, save for the handful of climbers who try to reach its summit each summer.

"Glaciers are a really unique archive," Lemmen said.

But even in summertime the conditions are inhospitable to say the least, with frequent storms and nighttime temperatures dropping to -30 C (-22 F).

The base camp at 2,800 meters (9,186 ft), and two camps for scientists at higher elevations, will be far from where weary mountain climbers have trudged to reach the peak of the mountain -- so deep in the ice field they can be seen only from an airplane of reached by expert mountaineers.

Scientists have previously taken ice cores from Greenland and Canada's eastern Arctic, but have yet to study climate change on the Pacific Ocean side of North America -- from where many North American weather influences emerge.

The last time an ice core was taken from Logan was in 1980, but technology has improved to allow scientists to extract as large a sample as the one planned.

"Logan's a pretty Pacific creature," said David Fisher, principal investigator on the expedition. "It's the only place that will see a good Pacific record."

The possibility exists that volcanic ash could be found from eruptions in 4000 BC in Alaska's Aleutian range, or that airborne pollen from Siberia, China or Japan may also be detected, scientists said.

Summit leader Mike Dumuth, who has scaled Mount Logan several times, said the expedition will provide many challenges -- thin high-altitude air, low temperatures and increased ultraviolet radiation at the higher elevation.

"You're freezing your feet but you're getting sunburned at the same time," Dumuth said.

Mount Logan became the center of controversy when the ruling Liberal party announced it would change the name of the peak, named after geologist Sir William Logan, to Pierre Trudeau after the Liberal prime minister who died last October.

The Liberals quietly dropped the plan because of public opposition to the name-change.