Digging deep into our climate's past

John Thompson

The key to unlocking 1,000 years of Pacific Northwest climate data is locked in a 600-foot-thick sheet of ice on British Columbia’s Mount Waddington—and Western Washington University geologist Doug Clark knows just how to get it.

The data is trapped in the ice; layer upon layer of hundreds of years of storms, droughts, volcanic eruptions, blizzards, pollution and more, sealed within a solid chunk of sky-blue ice 200 meters deep.

"That ice is like a time capsule," Clark said. "It records climate change and weather events precisely, year by year and, in some cases, event by event. On the West Coast, we’ve only got about 100 years of instrument-supplied weather data; even less for the mountains, where much of our water supply originates. The information locked in that ice field will multiply our known data by an order of magnitude."

Mount Waddington, at 13,186 feet, is the highest peak in B.C.’s Coast Range and is circled by a forbidding series of jagged peaks and deep gorges that reach down to the head of Bute Inlet, about halfway between Whistler and Bella Coola.

Near the mountain’s crest, more than 10,000 feet above sea level, is a broad, flat expanse, a saddle between two peaks that forms an enduring sheet of solid ice. At this elevation, the ice rarely melts; even in the summer, most precipitation this high falls as snow or ice.

"In summer, it is cool, dry, and remarkably flat—absolutely perfect for our sampling," Clark said.

This past summer, as part of a pilot grant funded by the National Science Foundation, WWU and the Canadian Foundation for Climate and Atmospheric Sciences, Clark and his co-researcher on the project, University of Washington geologist Eric Steig, were transported to the Waddington ice field by helicopter. There they used ground-penetrating radar to find the thickness of the ice sheet and take preliminary ice-core samples. What the radar told them was far beyond what they had even hoped: The sheet was more than 600 feet thick, a veritable Farmer’s Almanac of climate-change data for the past millennium.

"Now we know it’s there; we just have to go get it," Clark said.

Clark and Steig are applying for a $300,000 grant from the National Science Foundation to continue their research next summer, when they hope to retrieve ice cores from the surface all the way to the bedrock, 600 feet below.

"It would be a fantastic chunk of information," Clark said. "Essentially, we’d use it to understand how local climate responds to broader, regional forces like El Niño or solar changes. Understanding how natural climate change works is crucial to discerning how the climate will continue to respond to the pressures placed on it in the future."

Beyond Mount Waddington, Clark hopes to make a similar sampling trip to the Lloyd George ice field in Northeast B.C.’s Rocky Mountains.

"That’s a completely different climate system, much colder and drier than the B.C. coast," he said. "An ice-core record from that glacier might provide a great counterpart to the wet coastal record at Mount Waddington.

"But will it? We’ll see."

Monday, July 20, 2009