Posted January 25, 2019
"At present, the Arctic is warming two or three times faster than the rest of the world, so natural glaciers and ice caps will react more quickly," said Simon Pendollton, a PhD student at INSTAAR's Institute of Arctic and Alpine Studies ).
"Unlike the biology that has spent the last three billion years in developing schemes to avoid the impact of climate change, the glaciers have no survival strategy," said Gifford Miller, senior research author and professor of geology at CU Boulder . "They behave well, responding directly to the summer temperature. If the summer is warm, they immediately retreat; if summer is cool, they are advancing. This makes them one of the most reliable proxy for summer temperature change. "
The glacier retreat in the Canadian Arctic has uncovered landscapes that have not been free of ice for more than 40,000 years, and the region can experience its warmest century through 115,000 years, the new study by the University of Colorado at Boulder opens. New research uses radiocarbon dating to determine the age of plants harvested at the edges of 30 ice caps on the island of Baffin, west of Greenland.
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Baffin is the fifth largest island in the world, dominated by deep-cut fjords, separated by tall, low embossed fabrics. The thin, cold plateau ice acts as a natural cold storage, preserving the ancient moss and lichens in its initial position of growth for millennia. Over the last decades, the island has undergone significant warming in the summer.
"We travel to the retreating ice fields, try the new exposed plants preserved on these ancient landscapes and the carbon date of the plants to get the feeling when the ice has spread over that place," says lead author Pendleton. "Since the dead plants are effectively removed from the landscape, the radiocarbon age of the rooted plants is the last time the summers were warm on average, like those of the last century"
In August, researchers collected 48 plant samples from 30 different Baffin ice caps, covering a number of heights and exposures. They also took samples of quartz from each site to further establish the age and history of the ice cover of the landscape.
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After the specimens were processed and radiocarbon in the laboratories of the Institute of Arctic and Alpine Studies (INSTAAR) at CU Boulder and at the University of California, Irvine, the researchers found that these ancient plants in all 30 ice caps were probably continually covered by the least 40,000 years.
Compared to the temperature data reconstructed by the Baffin and Greenland ice cores, the results show that today's temperatures represent the warmest century in the region for 115,000 years and that Bafffin can be completely free of ice in the next few centuries.
"You usually expect to see different plant ages in different topographical conditions," says Pendleton. – A high altitude location can hold the ice longer, for example. But the degree of warming is so high that everything melts everywhere.
"We have not seen anything like that before," Pendleton said.
The Daily Galaxy through the Colorado University in Boulder