In a new research, scientists have used carbon dating method to calculate the age of relic moss samples exposed by modern Arctic warming. Had the moss been exposed earlier, they might have been destroyed by erosion. In other words, the temperatures in the Arctic currently are warmer than any time since mosses were originally buried. The temperature rises on Baffin Island, in the Canadian high Arctic have thus exposed ancient Polytrichum mosses, trapped beneath the ice for thousands of years. The research is published in Geophysical Research Letters.
The scientists for this research collected 365 samples of recently exposed biological material from 110 different locations, cutting a 1000 kilometer long transect across Baffin Island. They obtained 145 viable measurements through radiocarbon dating out of the samples.
The researchers found that most of their samples date from the past 5000 years, when a period of strong cooling overtook the Arctic. However, the authors also found older samples which were buried from 24,000 to 44,000 years ago.
The records suggest that in general, the eastern Canadian Arctic is warmer now than in any century in the past 5000 years, and in some places, modern temperatures are unprecedented in at least the past 44,000 years. The observations, the authors suggest, show that modern Arctic warming far exceeds the bounds of historical natural variability.
"The great time these plants have been entombed in ice, and their current exposure, is the first direct evidence that present summer warmth in the Eastern Canadian Arctic now exceeds the peak warmth there in the Early Holocene era", said Gifford Miller, from the University of Colorado. "Our findings add additional evidence to the growing consensus that anthropogenic emissions of greenhouse gases have now resulted in unprecedented recent summer warmth that is well outside the range of that attributable to natural climate variability."
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