Once Entombed in Ice, Ancient Moss Samples Reveal Unprecedented Arctic Warming [VIDEO]
Once trapped under ice for thousands of years, ancient moss samples collected from Baffin Island, in the Canadian high Arctic, provide evidence of a global warming trend that suggests that temperatures there now are warmer than during any sustained period since the mosses were originally buried, according to new study.
The research builds off work published last year by Gifford Miller, a research at Institute of Arctic and Alpine Research at University of Colorado, Boulder.
Then, Miller reported that temperatures in the Canadian high Arctic have been higher in the last 100 years than they have been during any century in the preceding 44,000 years.
In the current edition of Geophysical Research Letters, a new study by Miller and his colleagues focuses on moss samples collected as part of the initial research.
Miller contends that the moss was exposed after thousands of years trapped under ice as a direct result of modern warming. Had the ice melted at any other time, Miller argues, the moss would have been destroyed by erosion and would not have survived to be found today.
As such, the researchers contend that temperatures in the Arctic now must be warmer than they were during any sustained period since the mosses were initially buried.
"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," Miller said. "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."
The mosses Miller and his team collected came from a variety of locations along a 1,000-kilometer-long swath of Baffin Island. A total of 365 plant samples were collected from 110 locations that represented a range of altitudes.
Of the 365 samples, 145 were viable enough for radiocarbon dating. They found that most of the samples dated from the past 5,000 years, which is when a period of strong cooling overtook the Arctic.
Some of the samples found were much older, dating between 24,000 and 44,000 years old.
"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 researchers said in a statement, adding that current Arctic warming "far exceeds the bounds of historical natural variability."