The last time the Arctic was this warm was 120,000 years ago

Average summer temperatures in the Eastern Canadian Arctic during the past 100 years are hotter than they have been in at least 44,000 years, and possibly as long as 120,000 years, according to a new study.

The study of mosses emerging from beneath receding glaciers on Baffin Island — the world's fifth-largest island located west of Greenland — confirms that rapid Arctic warming has already put parts of the region in new climatic territory.

Arctic warming is transforming the Far North by melting sea and land ice, speeding spring snowmelt, and acidifying the Arctic Ocean. Arctic warming may even be redirecting the jet stream in the northern midlatitudes, making some types of extreme weather events more likely in the U.S. and Europe.

It's significant because it means that manmade emissions of greenhouse gases have pushed the climate in this part of the world beyond the previous, naturally driven warm period, when incoming solar energy during the Northern Hemisphere summer was about 9 percent greater than it is today.

Miller said he and his colleagues were "shocked" by their findings. "Our data pretty clearly demonstrates that the observed warming now exceeds any plausible explanation by natural variability. There is no other explanation that anybody has put forward outside of greenhouse gas emissions that can possibly meet what we've observed."