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Penny Ice Cap heats up
Stable for years, now 10 degrees warmer at summit; however, 'this ice cap is not going anywhere soon'

Casey Lessard
Northern News Services
Published Saturday, May 5, 2012

After 50 years without significant change, measurements from the past year show the Penny Ice Cap's summit has warmed dramatically since 2000, Geological Survey of Canada researcher Christian Zdanowicz said at a Nunavut Research Institute presentation on April 30.

NNSL photo/graphic

Auyuittuq National Park warden Monty Yank drills a shallow snow core on Penny Ice Cap to measure snow density. - photo courtesy of Nicole Schaffer

Zdanowicz came to his conclusions after drilling ice cores into the Penny Ice Cap the last two springs, having recently returned from two-week trip to Auyuittuq National Park in April.

Although surface temperatures vary, "if you're measuring at 10 metres down, you will get a flat line, where temperature will not change much throughout the year," he said, noting it will be slightly above the average surface temperature. For the Penny Ice Cap, the 10 metre temperature consistently stayed at about -13 C in readings made from 1953 to 2000. But in 2011 and 2012, the temperature read -3 C, a 10-degree increase.

"That's a huge amount," he said. "It means over the last 10 to 15 years, the temperature inside the ice cap has risen by nearly a degree per year. The only way we can account for this change is that there has been more melt near the surface. That's quite a dramatic change and you don't see that very often."

The Penny Ice Cap, between Pangnirtung and Qikiqtarjuaq, is a remnant of the Ice Age. Each winter, snow collects on top of the glacier. If the snow is heavy enough, it will compress into air-filled, bubbly ice. If a summer is hot enough, some or a lot of it melts into a layer of solid, bubble-free ice. Scientists can gauge surface temperatures by extracting ice cores and measuring the thickness of this once-wet ice layer.

"Summer temperatures are getting warmer over time," Zdanowicz said, referring to readings since 1965. "The percentage of an ice core that is made up of that re-frozen ice has been steadily going up."

He said winter temperatures have shown the same trend in the region.

As the temperature has increased, so has the length of the melt season, he said.

"As soon as there is a small amount of liquid water in the snowpack, the amount of microwaves emitted increases all of a sudden."

Satellites have been reading when these microwaves start and stop being emitted, which tells scientists the length of the melt season. Zdanowicz cited research by the University of Sherbrooke's Florent Dupont, who noted that since 1979, the length of the melt season of the Penny Ice Cap and the Barnes Ice Cap west of Clyde River "have essentially doubled."

Since the Little Ice Age, from about 1350 to 1850, the summer melt affected about 30 per cent of the winter gains, whereas now the summer melt is losing "almost 100 per cent" of the winter gains, he said.

As temperatures and the length of the melt season increase, consequences will follow, including flooding in the rivers and lands below the 2,000-metre-high ice cap.

"You might get ice dams bursting," Zdanowicz said, "and this may eventually be a serious hazard for trekkers in Auyuittuq Pass if we're getting these kinds of floods. It is a concern."

He also predicts the structure of ice and rate of freezing in the bays and fjords of Baffin Island will change as fresh glacier water mixes with the Arctic Ocean's salt water.

Only Greenland, Antarctica and Alaska are losing their glaciers faster. However, Penny Ice Cap creates a micro-climate that helps sustain itself, so "this ice cap is not going anywhere soon," he said. "We know that it survived the early Holocene warming period after the last Ice Age. It is melting at an accelerated rate, but it will take centuries if not millenia before it vanishes completely."

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