Temperatures in Canada's Arctic were about 19 C warmer two million years ago than they are currently, according to a new study.
And that means a small increase in global greenhouse gases could lead to a large drop in the amount of glacial ice in Canada's northernmost region, according to a group of scientists led by researchers at the University of Colorado.
"As temperatures approach zero degrees Celsius, it becomes exceedingly difficult to maintain permanent sea and glacial ice in the Arctic," said Ashley Ballantyne, a University of Colorado geology professor and study member.
The six-person research team — which included David Greenwood of Brandon University and Natalia Rybczynski of Ottawa's Canadian Museum of Nature — figured that Ellesmere Island, located north of Baffin Bay, exhibited the higher temperatures in pre-historic times despite levels of carbon dioxide only slightly greater than they are now.
Back then, Canada's North was a much warmer place with active animal and plant life.
The researchers set the island's average annual temperature in that time at 0 C and the level of carbon dioxide at 400 parts per million of all molecules in the atmosphere.
Ballantyne and the other scientists made their calculations by using fossilized wood and the well-preserved remains of prehistoric plants and soil bacteria from the island.
However, the group's discovery indicates that Ellesmere Island could be heading back to its balmy past. That is because the current carbon-dioxide levels in the area are closer to 390 parts per million, near the levels now associated with pre-historic temperatures.
"Our findings indicate that CO2 levels of approximately 400 parts per million are sufficient to produce mean annual temperatures in the High Arctic of approximately zero degrees Celsius," Ballantyne said.
As the temperature rises, the region's ability to maintain its permanent ice fields will decrease, she said.