Existing levels of greenhouse gases may be enough to push Arctic temperatures 19°C higher, a recent study has found.
A University of Colorado at Boulder scientific expedition to Ellesmere Island in the high Arctic found evidence that the ice cap may be far more sensitive to warming than had been thought, the team said on June 29.
The team used fossil records to measure temperatures on the island during the Pliocene period — 2.6 to 5.3 million years ago.
The research confirmed the area was mostly ice-free and about 19°C warmer on average than it is now.
Today, Ellesmere Island is a polar desert. Temperatures range from about -38°C in winter to a summer average of 9°C.
But the shock discovery was that the amount of carbon dioxide in the atmosphere during the Pliocene was just 400 parts per million. Today’s concentration is 390ppm.
The burning of fossil fuels for energy pushes that figure up about 2ppm every year.
In the past two centuries, greenhouse gases have risen from a pre-industrial level of 280ppm.
Ashley Ballantyne, from the university’s geological sciences department, said the findings suggest current levels of greenhouse gases could eventually bring temperatures in the High Arctic to about 0°C, putting the Arctic ice cap at immediate risk.
“As temperatures approach 0°C, it becomes exceedingly difficult to maintain permanent sea and glacial ice in the Arctic”, he said.
“Thus, current levels of CO2 in the atmosphere of approximately 390ppm may be approaching a tipping point for irreversible ice-free conditions in the Arctic.”
Team members intend to return to the site to conduct more research. The site is the only place in the High Arctic known to have Pliocene fossil remains.
However, the site itself is directly threatened by the fossil fuel industry. Team member Jaelyn Eberle said a proposed coalmine near the site, by Canadian company WestStar Resources Inc “could damage such sites and they will be lost forever”.