Published: Fri, February 01, 2019
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New evidence reveals Arctic summers now hottest for 115,000 years

New evidence reveals Arctic summers now hottest for 115,000 years

The study, published January 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 researchers studied the remains of mosses and lichens.

Processing the samples, and radiocarbon dating them in labs at the Institute of Arctic and Alpine Research and the University of California Irvine, showed that the ancient plants at all 30 ice caps have likely been continuously covered by ice for at least the past 40,000 years.

Thanks to their study, the researchers managed to study the plants in an Arctic landscape and learn more about the soil under the Canadian Arctic glaciers, which has now become visible after 40,000 years due to glacial melt.

The plants can give researchers a peek into the history of the location, determine the last time that summers were as warm in the past century as they are today, and when the ice that covered the landscape had advanced.

Pendleton and colleagues' research is based on plants collected at the edge of ice caps on Baffin Island, the fifth largest island in the world.

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.

"The Arctic is now warming two to three times faster than the rest of the globe, so naturally, glaciers and ice caps are going to react faster", Simon Pendleton, doctoral researcher at Boulder's Institute of Arctic and Alpine Research, said in a news release.

"To be able to see it and walk on the ice cap and understand we're in a time that's exposing landscapes that haven't seen sunlight in possibly 120,000 years, that has a profound effect", Pendleton said. They're well behaved, responding directly to summer temperature. "This makes them one of the most reliable proxies for changes in summer temperature", said Gifford Miller from CU Boulder, referring to the reactions of glaciers to climate change. Upon analysis, the researchers found that samples collected from all locations have been covered in ice in the past 40,000 years.

The level of carbon dioxide that is present in the atmosphere will reach a new record in 2019, heralding warmer summers that will come in the future.

The findings about the plants' ages, combined with temperature data reconstructed from Greenland ice cores, suggest that this is the region's warmest century in about 115,000 years, the study says. Like the rest of the Arctic circle, the region is experiencing warming at a rate twice the global average - so much so that plants and moss that haven't been exposed since the last ice age are now starting to creep through the melting ice.

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