Home / Science / Ancient plants have not revealed arctic summers so hot for 115,000 years

Ancient plants have not revealed arctic summers so hot for 115,000 years

Glaciers and ice caps on Baffin Island in Arctic Canada have dramatically receded in recent decades, revealing ancient landscapes that may have been covered in ice for about 1
15,000 years.
Photo: Gifford Miller, University of Colorado Boulder / INSTAAR

The most recent sign of the intricate nature of the Arctic is that moss, which has not seen daylight for at least 40,000 years, runs on Canadian Baffin Island thanks to the increasingly balmy summers of icecaps. Based on this and other findings, research published on Friday in Nature Communications indicates that the summers in the Canadian Arctic have not been so warm for 115,000 years or more.

Even in the wild world of statistics about how climate change is changing the Arctic environment, this one stands out.

"This study shows that we exposed landscapes 120,000 years ago," said study lead author Simon Pendleton from the University of Colorado's Institute of Arctic and Alpine Research. "Our last century heat is likely to be greater than every century in the last 120,000 years."

Preserved old moss collected on the edge of a retreating ice cap on Baffin Island.
Photo: Gifford Miller, University of Colorado Boulder / INSTAAR

In order to arrive at this conclusion, Pendleton and his colleagues relied on the ice of Baffin Island and the bizarre quirks of geography that enabled it to reveal its secrets divulge. The island is home to deep fjords and plateaus, the latter covered by ice caps. Ice caps are huge chunks of ice, much like glaciers, but there is one major difference. Where glaciers under the earth stream and grind on the earth, icecaps are static. This means that everything that is on the ground when it is formed is preserved instead of getting dusty.

For ages, ice has occupied the plateaus and walls of Baffin Island. In some summers it would melt, but in general, low temperatures and snow kept things fairly balanced. Now, climate change has upset that balance, causing the Arctic to heat up twice as fast as the rest of the world. This resulted in more summer melt that has exposed moss and lichen on the edges of the icecaps.

Pendleton and others collected samples from around 30 ice caps and conducted radio-carbon dating to determine their age. The results show that the mosses are at least 40,000 years old (and in a wild side note, some of the mosses were returned to laboratories and revived as arctic zombie plants.)

But here's the thing: 40,000 years close to the edge of the story, which you can investigate with radiocarbon dating. It's also by chance in the middle of an ice age. As a result, Pendleton and his colleagues searched other records, including nearby ice measurements from Greenland. Cross-referencing the plants shows that the area has been covered with ice for more than 40,000 years, and that the summers of our new climate are likely to bubble more than anything else in about 115,000-120,000 years.

As ice caps recede even further, they could expose even more ancient landscapes. By refining their measurements, scientists can then predict what the Arctic will look like as climate change continues to transform it. Even without the radiocarbon dating, Pendleton said it was clear how fast Baffin Island would change to a new state. Every year, changes become more visible to the naked eye.

"To be able to see it and to go to the ice cap and understand that we are in a time when landscapes are visible that have not seen sunlight in 120,000 years. that has a profound effect, "he said.

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