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Ancient plants show that the Arctic summer was not so hot for 115,000 years



The last sign of how winding the Arctic is: a moss that has not seen daylight for at least 40,000 years, falls out of the ice caps on the Canadian island of Baffin due to an ever cooler summer. Based on this and other evidence published in Nature connection Friday suggests that the summer in the Canadian Arctic has not been so warm for 115,000 years or more.

Even in the wild world of statistics on how climate change is transforming the Arctic, this one stands out.

"This study indicates that we expose landscapes that are 120,000 years old," said study lead author Simon Pendleton of the Institute of Arctic and Alpine Studies at the University of Colorado. Gizmodo“Our last century of heat is probably more than any century in the last 120,000 years.”

To reach this conclusion, Pendleton and his colleagues relied on the ice of Baffin Island and the strange features of geography that allowed him to reveal his secrets. The island is home to deep fjords and high plateaus, the latter of which are covered with ice caps. Ice caps are huge pieces of ice, very similar to glaciers, but there is one key difference. Where glaciers flow and fall to the ground beneath them, ice caps are still. This means that everything that is on earth, when they are formed, is preserved, not turned into dust.

For centuries, ice has occupied the plateau and walls of Baffin Island. In some summers there would be melting, but on the whole, low temperatures and snow kept things largely in balance. Now climate change has disturbed this balance, forcing the Arctic to warm up twice as fast as the rest of the world. This led to more summer melting, which exposed the moss and lichens at the edges of the ice caps.

Pendleton and others collected samples from about 30 ice caps and conducted radiocarbon dating to determine their age. The results show that mosses are at least 40,000 years old (and on the wild side they noticed that some of the mosses were returned to the lab and brought back to life as arctic zombie plants).

But here's the thing: 40,000 years is close to the edge of history, which can be found on radiocarbon dates. It also happens to taste in the middle of the ice age. This led Pendleton and his colleagues to search for other records, including measurements of ice cover in Greenland. Cross references to plants show that the area has been covered with ice for much longer than 40,000 years, and that the summer of our new climate is likely to be stronger than anything else, in about 115,000-120,000 years.

As the ice caps recede even further, they may expose even more ancient landscapes. By refining their measurements, scientists can predict what the Arctic will look like as climate change continues to change. Pendleton said that even without radiocarbon analysis, it is clear how quickly Baffin Island is transitioning to a new state. Every year changes are becoming more visible with the naked eye.

“To see it, walk on the ice cap and understand that we are at a time when we see landscapes that had no sunlight, perhaps for 120,000 years, it has a profound effect,” he said.


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