Arctic temperatures warmest in more than 10,000 years

Study provides further evidence of rapid climate change in the North, moving us into uncharted territory, say scientists.

Arctic temperatures are the warmest they've been in more than 10,000 years, according to a new University of Alberta study that highlights alarming rates of climate warming and thawing of permafrost in Northern Canada.

"We've known that the last few decades have been very warm, but we've found that temperatures are on the order of two degrees Celsius warmer than any time in the last 10,000 years-that was a surprise," said U of A environmental scientist Duane Froese, who is Canada Research Chair in Northern Environmental Change and a co-author of the study.

He explained that the rise in temperature has caused permafrost thaw across the Arctic to increase rapidly, destabilizing soil carbon, which may further accelerate warming by releasing increased amounts of greenhouse gases.

"This is potentially the new normal, and if it accelerates in the near future, it threatens to further amplify global climate change," said Trevor Porter, the lead author on the paper who was a post-doctoral fellow supervised by Froese and is now an assistant professor at the University of Toronto.

"All indications from this new study are that temperatures and the impacts of recent warming are only picking up and getting stronger," said Froese. "We are moving into uncharted waters with respect to climate change in the North."

Temperatures climbing

The researchers examined permafrost and found that previous record highs occurred during the early Holocene-about 9,900 and 6,400 years ago. But even without the unique circumstances of that period, current Arctic temperatures have exceeded those records.

"This period, called the early Holocene thermal maximum, occurred when the Earth's axis was more strongly directed toward the sun. This was a time when permafrost was degrading rapidly," said Froese.

"This new study shows that temperatures today are even warmer than they were during this period and so we should expect that the recent impacts of warm temperatures are just the beginning of the rapid thawing of permafrost across the North."

The rising temperatures have had implications across Northern Canada already, with other recent studies reporting record levels of mercury released by thawing permafrost, a 6,000 per cent increase in landslides, or slumps, caused by thawed permafrost on Banks Island, and evidence that Canada is warming at twice the global rate.

"Clearly, we need to come to terms with the impacts of these warmer temperatures and consequences for northern communities, infrastructure and lifestyles," said Froese.

The U of As participation in the study also included work by graduate students Sasiri Bandara and Lauren Davies, supervised by Froese.

The study, "Recent Summer Warming in Northwestern Canada Exceeds the Holocene Thermal Maximum," was published in Nature Communications.