The methane seeps found are in Alaska and Greenland in lakes along the margins of ice cover.
Samples showed that some of these are releasing the ancient methane, perhaps from natural gas or coal deposits underneath the lakes, whereas others are emitting much younger gas, presumably formed through decay of plant material in the lakes.
"We observed most of these cryosphere-cap seeps in lakes along the boundaries of permafrost thaw and in moraines and fjords of retreating glaciers," the report, led by Katey Walter Anthony from the University of Alaska at Fairbanks (UAF), said.
Emphasizing the point that warming in the Arctic is releasing this long-stored carbon.
"If this relationship holds true for other regions where sedimentary basins are at present capped by permafrost, glaciers and ice sheets, such as northern West Siberia, rich in natural gas and partially underlain by thin permafrost predicted to degrade substantially by 2100, a very strong increase in methane carbon cycling will result, with potential implications for climate warming feedbacks."
The region stores vast quantities of the gas in different places - in and under permafrost on land, on and under the sea bed, and - as evidenced by the latest research - in geological reservoirs.
"The Arctic is the fastest warming region on the planet, and has many methane sources that will increase as the temperature rises," commented Prof Euan Nisbet from Royal Holloway, University of London, who is also involved in Arctic methane research.
"This is yet another serious concern: the warming will feed the warming."