Russian scientists have discovered that the Arctic is releasing hundreds, perhaps thousands, of enormous plumes of methane from the seafloor directly into earth's atmosphere.

The scale and volume of the methane release has astonished the head of the Russian research team who has been surveying the seabed of the East Siberian Arctic Shelf off northern Russia for nearly 20 years.

This has some people messing their drawers because it’s strongly reminiscent of what is probably the worst possible climate scenario imaginable, a feedback loop so humongous and destructive that it would lead to runaway warming that makes today's runaway warming look tame by comparison. The last time this happened, it poisoned 90 percent of all life on earth with hydrogen sulfide gas, in a process described by paleontologist Peter Ward as "life killing itself off."

Methane is an extremely powerful greenhouse gas, up to 72 times more potent than carbon dioxide, depending on how you measure it. It’s long been known that reduced ice cover in the Arctic could trigger massive methane releases, warming the planet even further. That threat has led some to call for radical geoengineering of the Arctic by 2013, though most scientists say that's premature. (Or at least, they said that before.)

A 2010 paper in Science led climate scientist David Archer to declare that Arctic methane shouldn't scare us, because our most immediate climate threat comes from the carbon dioxide already in the atmosphere.

CO2 is plenty to be frightened of, while methane is frosting on the cake. Imagine you are in a Toyota on the highway at 60 miles per hour approaching stopped traffic, and you find that the brake pedal is broken. This is CO2. Then you figure out that the accelerator has also jammed, so that by the time you hit the truck in front of you, you will be going 90 miles per hour instead of 60. This is methane. Is now the time to get worried? No, you should already have been worried by the broken brake pedal. Methane sells newspapers, but it’s not the big story, nor does it look to be a game changer to the big story, which is CO2.

Another paper in 2010 from the Journal of Geophysical Research asserted that even under the worst warming scenarios, the methane coming out of the Arctic ocean couldn't have anything to do with planetary warming. (h/t Colin Schultz)

But it’s not like we know everything there is to know about Arctic methane. Science moves slowly, perhaps too slowly to deal with a planetary emergency. Already, this discovery has blown at least one hypothesis out of the water — the idea that even if there were large releases of methane from the arctic, they would be contained in the ocean by a cap of cold water and methane-consuming microbes. So much for that.

Cow farts and the occasional Arctic plume aside, so far it seems like humans remain the dominant source of methane in the atmosphere. But new methane emissions have got nothing on the malign methane genie bottled up in the permafrost. If global warming releases that huge store of greenhouse gas, it could — pardon the expression — snowball out of control.