Christopher Intagliata explains:

The Arctic is warming twice as fast as the rest of the planet, on average. And as permafrost becomes, well, not so perma, microbes are warming up, feasting on organic compounds in the thawed soil. The microbes then belch methane—a potent greenhouse gas. Meaning that the warming Arctic could become a big source of carbon pollution. 

But maybe it won't. Because it turns out there are also a lot of microbes that like to snack on the methane waste their buddies emit. In fact, some 90 percent of the methane bubbling up through Arctic soils is already soaked up this way.

Now researchers report that they've found a new strain of methane-eating microbes in soil samples from Axel Heiberg Island, in the Canadian high Arctic. The soils on the island are not rich in carbon, meaning there's not a lot of methane waste. So these still-unnamed bacteria instead harvest the gas straight out of the air. And as that air warms up, they’re getting hungrier. The scientists project that as temperatures rise over the next century, the bugs could gobble up anywhere from five to 30 times the amount of methane they eat today. The study appears in The ISME Journal. [MCY Lau et al, An active atmospheric methane sink in high Arctic mineral cryosols]

Most Arctic permafrost—87 percent—is actually carbon-poor, minerally stuff like the soil on Axel Heiberg Island. Meaning much of the Arctic could soon be sucking up methane. It's still too early to say whether the region could actually become a carbon sink. But the researchers say that at the very least climate models need to reflect this latest nuance of our warming planet.