Arctic Hasn't Been This Warm in 120,000 Years, Study Suggests

The last century marked a period of unprecedented warmth for the Arctic, according to a new study. The report is the first direct evidence the Eastern Canadian Arctic is warmer now than it was during the Early Holocene, when roughly 9 percent more energy from the Sun reached the Northern Hemisphere.

Using dead moss clumps taken from receding ice caps on Baffin Island, University of Colorado researchers determined that the average summer temperatures in the Eastern Canadian Arctic for the last 100 years were higher than any previous century going back at least 44,000 years, and possibly as many as 120,000.

Radiocarbon dates revealed that moss samples from four different ice caps had laid under the ice for at least 44,000-51,000 years -- as far back as the dating method goes. Knowing this, and knowing that the Earth was experiencing a glaciation stage prior to then, the researchers hypothesize that temperatures in the Canadian Arctic haven't been as high as they are today for some 120,000 years.

"The key piece here is just how unprecedented the warming of Arctic Canada is," Gifford Miller, geological sciences professor and study lead, said in a statement. "This study really says the warming we are seeing is outside any kind of known natural variability, and it has to be due to increased greenhouse gases in the atmosphere."

In order to reconstruct the history of Baffin Island's climate beyond the reach of radiocarbon dating, Miller and his team used ice cores previously gathered from the neighboring Greenland Ice Sheet. The cores corroborated the team's hypothesis, suggesting the minimum amount of time since Arctic temperatures were as high as the last century's was 120,000 years ago.

"Although the Arctic has been warming since about 1900, the most significant warming in the Baffin Island region didn't really start until the 1970s," Miller said. "And it is really in the past 20 years that the warming signal from that region has been just stunning. All of Baffin Island is melting, and we expect all of the ice caps to eventually disappear, even if there is no additional warming."