Reporting to the European Geophysical Union last year, the scientists, affiliated with the University of Alaska and the Russian Academy of Sciences, cited "extreme" saturation of methane in surface waters and in the air above. They said up to 10% of the undersea permafrost area had melted, and it was "highly possible" that this would open the way to abrupt release of an estimated 50 billion tons of methane.
Depending on how much dissolved in the sea, that might multiply methane in the atmosphere several-fold, boosting temperatures enough to cause "catastrophic greenhouse warming," as the Russians called it. It would be self-perpetuating, melting more permafrost, emitting more methane.
Some might label that alarmism. And Stockholm University researcher Orjan Gustafsson, a partner in the Russians' field work, acknowledged that "the scientific community is quite split on how fast the permafrost can thaw."
But there's no doubt the north contains enough potential methane and carbon dioxide to cause abrupt climate change, Gustafsson said by telephone from Sweden.
Canada's pre-eminent permafrost expert, Chris Burn, has trekked to lonely locations in these high latitudes for almost three decades, meticulously chronicling the changes in the tundra.
On a stopover at the Aurora Research Institute in the Mackenzie Delta town of Inuvik, the Carleton University scientist agreed "we need many, many more field observations." But his teams have found the frozen ground warming down to about 80 meters, and he believes the world is courting disaster in failing to curb warming by curbing greenhouse emissions.
"If we lost just 1% of the carbon in permafrost today, we'd be close to a year's contributions from industrial sources," he said. "I don't think policymakers have woken up to this. It's not in their risk assessments."
How likely is a major release?
"I don't think it's a case of likelihood," he said. "I think we are playing with fire."