Title : Receding glaciers in Canadian Arctic reveal landscapes not seen for 40,000 years
link : Receding glaciers in Canadian Arctic reveal landscapes not seen for 40,000 years
Receding glaciers in Canadian Arctic reveal landscapes not seen for 40,000 years
CTVNews.ca Staff</span>
Published Monday, January 28, 2019 10:55PM EST
Last Updated Tuesday, January 29, 2019 10:01PM EST
Researchers studying glacial retreat on Baffin Island in the Canadian Arctic have discovered landscapes and plant life that have not been seen for more than 40,000 years.
The study, published Jan. 25 in the journal Nature Communications, also found that summers in the Canadian Arctic are warmer now than “any century in at least 115,000 years.”
“The Arctic is currently warming two to three times faster than the rest of the globe, so naturally, glaciers and the ice caps are going to react faster,” Simon Pendleton, the study’s lead author and a doctoral researcher at the University of Colorado, Boulder’s Institute of Arctic and Alpine Research, said in a statement.
“It’s stunning that you’re standing on the landscape that, not only has no humans ever stood on, but [that has] been ice-covered for over 100,000 years,” he told CTV News Channel.
He explained that during past cold climates, glaciers expanded and during warmer periods, those glaciers retreated.
“As these glaciers retreat, they’re exposing landscapes underneath them,” Pendleton said. In other words, once glaciers in Canada’s eastern Arctic region thaw, they give researchers a snapshot of Earth’s past.
“These glaciers in Baffin Island, in particular, are unique in that they’re frozen to the bed underneath them,” he said. “So as they expand over a plant [during periods of colder climates], they’ll actually preserve it in its growth position -- where it was living before the glacier expanded.”
Between 2010 and 2015, he and his team made trips to Baffin Island in Nunavut and noticed the glaciers there were rapidly shrinking. Due to global climate change, they saw them recede by tens of metres between each of their visits.
To draw their conclusions, researchers used radiocarbon dating to determine the ages of 48 mosses and lichen samples collected last August at 30 ice caps encompassing a range of elevations and exposures in Baffin Island in Nunavut.
The samples were preserved in the exact same spots where they once grew, beneath ice caps that cover the island’s high-elevation, low-relief plateaus. As the ice caps have receded, plants -- from moss to lichen -- have been exposed.
The samples were lacking radiocarbon, which suggests that they last saw the light of day at least 40,000 years ago. Researchers then cross-referenced those radiocarbon tests with measurements of radiocarbon in rock samples nearby. They, too, were bereft of radiocarbon.
According to the study, these results, combined with data from ice cores taken on Baffin Island and Greenland, suggest that the region is currently experiencing its warmest century in 115,000 years.
“These trends are likely to continue and remove all ice from Baffin Island within the next few centuries,” the study concluded, “even in the absence of additional summer warming.”
Now, Pendleton’s team hopes past-glacial fluctuations will help scientists predict how human-made climate change will effect Earth’s ecosystems in the coming decades.
He said some of his peers at the University of Colorado, Boulder have already begun that work.
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