Experts at the University of Colorado Boulder have found that the standard summer temperatures in the Eastern Canadian Arctic have risen drastically in the last 100 years as compared to any century in the last 44,000 years and perhaps as long ago as 120,000 years.
CU-Boulder geological sciences Professor Gifford Miller, study leader, said that the study is the first direct evidence the present warmth in the Eastern Canadian Arctic exceeds the peak warmth there in the Early Holocene, when the amount of the sun's energy reaching the Northern Hemisphere in summer was roughly 9 percent greater than today.
AdvertisementThe Holocene is a geological epoch that began after Earth's last glacial period ended roughly 11,700 years ago and which continues today.
Miller and his colleagues used dead moss clumps emerging from receding ice caps on Baffin Island as tiny clocks.
At four different ice caps, radiocarbon dates show the mosses had not been exposed to the elements since at least 44,000 to 51,000 years ago.
Miller said that since radiocarbon dating is only accurate to about 50,000 years and because Earth's geological record shows it was in a glaciation stage prior to that time, the indications are that Canadian Arctic temperatures today have not been matched or exceeded for roughly 120,000 years.
"The key piece here is just how unprecedented the warming of Arctic Canada is," said Miller, also a fellow at CU-Boulder's Institute of Arctic and Alpine Research.
Miller asserted that the study really suggests that the current warming is outside any kind of known natural variability and it has to be due to increased greenhouse gases in the atmosphere.
Studies by Greenland researchers indicate temperatures on the ice sheet have climbed 7 degrees Fahrenheit since 1991.
The study is published in the journal Geophysical Research Letters.