Study finds temperatures in eastern Arctic Canada at highest in at least 44,000 years

A new study of the eastern Canadian Arctic has shown that the average summer temperatures we've been seeing there over the past 100 years are higher than they've been in at least 44,000 years, and quite possibly up to 120,000 years.

As the ice on Baffin Island melts due to the unprecedented rate of warming we're seeing in the Arctic in recent years, preserved mosses are being exposed that have been trapped under the ice for thousands of years. A team of researchers led by Professor Gifford Miller, from the University of Colorado Boulder, examined these mosses using carbon dating techniques. Their results showed that the last time these mosses were exposed to air was, at the very least, sometime between 44,000 and 51,000 years ago. That includes being higher than the 'warming peak' during the early Holocene, roughly 11,000 years ago, when the Arctic was receiving about 9 per cent more radiation from the sun than it is today.

"The key piece here is just how unprecedented the warming of Arctic Canada is," Miller said in a CU-Boulder news release. "This study really says the warming we are seeing is outside any kind of known natural variability, and it has to be due to increased greenhouse gases in the atmosphere."

Also, since the age of the mosses was very close to the limit on how far back radiocarbon dating could show them, Miller and his team extended the timeline by examining gases trapped in ice cores collected from nearby Greenland. These showed that the last century's Arctic temperatures could actually be higher than they've been in around 120,000 years.

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The full timeline they constructed showed that temperatures in the Arctic had been cooling down for the past 5,000 years or so, by a little over 2.5 degrees C. This cooling trend ended after the 'Little Ice Age', sometime in the late 1800s, when the second industrial revolution was getting into full-swing, but it's more recent warming that's the true concern.

"Although the Arctic has been warming since about 1900, the most significant warming in the Baffin Island region didn't really start until the 1970s," Miller said in the news release. "And it is really in the past 20 years that the warming signal from that region has been just stunning. All of Baffin Island is melting, and we expect all of the ice caps to eventually disappear, even if there is no additional warming."

(Photo courtesy: Gifford Miller, University of Colorado Boulder)

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