Concerns about escape of CO2 and methane from Arctic permafrost revolve around whether, how much, and how fast emissions could be released. But a new Yale Forum video cautions that a warmer atmosphere poses real risks and, once started, such a release ‘will just go by itself.’

“Frozen dirt.”

Got it? If so, now you can better describe permafrost in those discussions around the dinner table. It’s any underground earth material that stays frozen for two or more consecutive years, Vladimir Romanovsky, Ph.D., of the University of Alaska Fairbanks, explains in a new “This is Not Cool” video produced by Peter Sinclair for The Yale Forum on Climate Change & The Media.

When it thaws, so do the microorganisms. With no oxygen, the microorganisms make methane, and with it they make carbon dioxide, Kevin Schaefer of the U.S. National Snow and Ice Data Centre explains.

The concern is that much of the carbon stored in permafrost — in frozen dirt — could be released into the carbon cycle, says scientist Charles Miller of NASA/Jet Propulsion Laboratory. The Arctic, Miller says, is being affected by warming faster and more significantly than models had predicted. Methane concentrations, and even CO2 concentrations, “that one might associate with flying near a large oil or natural gas production facility or even flying through the middle of a large city” can be observed from an airplane, he says. “They’re elevated that much. But when you look down at the surface, all you see is pristine wilderness, typically wetlands and rivers with sporadic forests and grassland.” Finding those concentrations so distant from those locations, Miller says, is “quite remarkable to me.”

It all comes down to how much of the carbon currently stored in the Arctic tundra will be released and over what period of time, Miller says. Will it be released over 100 or 150 years, or over a decade or two?

In the latter case, “the perturbation would be significantly larger,” Miller cautions.

“We have at least theoretical control” over human emissions of greenhouse gases, Romanovsky says. “And because of that, we feel that we can do something to change it if it’s necessary.

“In the case of thawing permafrost, there’s no way to control it or stop it. It just will go by itself.”

Nobel Laureate and former Energy Secretary Steven Chu cautions of “a reasonable possibility” that once started, emissions from Arctic permafrost could “even dwarf” human-caused GHG emissions. Chu expresses concerns in particular about global temperature increases of 4, 5, or 6 degrees C. “At that point, it’s completely out of our control … the release of the trapped carbon material in the Tundra just runs away …. We cannot go there.”

But might we? Anton Vaks, of Oxford University and colleagues have published a paper cautioning that the “tipping point” for permafrost melting may be quite lower, more like 1.5 degrees C above preindustrial global temperatures. “This is probably the tipping point,” Vaks cautions. (Since the late 1800s, global temperatures have increased about .8 degrees C.)

But “it’s not an all or nothing” situation, scientist Ben Abbott of the University of Alaska Fairbanks says. Limiting CO2 and greenhouse gas emissions will lead to lower releases of greenhouse gases from the permafrost, he says.

In that case, one can hope that it will be little more than “frozen dirt” in the first place. But it’s a big “If.”

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