First it was mysterious craters appearing in Siberia — possibly the result of the Earth belching methane as permafrost thaws and collapses.

Then scientists observed methane gas bubbling to the surface from the sea floor in the Arctic Ocean, where for eons it lay trapped in a flammable slush. The researchers who discovered the plumes — a joint team of Americans, Swedes and Russians on an expedition called the SWERUS-C3 — suspect the methane is escaping due to an influx of warmer water from the Atlantic Ocean, which, in turn, could be tied to climate change.

The release of methane on a large scale has long worried scientists. The greenhouse gas is 20 times more damaging to the Earth over a 100-year period than CO 2 , and is even more potent in the short term. Should the deposits trapped within the Arctic escape into the air, it could kick off a highly destructive climate feedback loop: The methane would cause rapid warming, which would melt more of the Arctic, which would release more methane, which would cause more warming.

This eventuality was the subject of an ominous commentary published in Nature last summer. It placed the cost of methane escaping into the atmosphere at $60 trillion — the size of the world economy. (Some climatologists argued that the article went too far.)

So do these recent observations — the craters, the plumes — mean a methane-fueled climate disaster has come sooner than previously feared?

We’re in trouble “if even a small fraction of Arctic sea floor carbon is released to the atmosphere,” tweeted widely-published climatologist Jason Box (with stronger phrasing) after the news of the plumes surfaced. “The trajectory we’re on is to awaken a runaway climate heating that will ravage global agricultural systems leading to mass famine, conflict. Sea level rise will be a small problem by comparison. We simply MUST lower atmospheric carbon emissions,” Box explained in a blog post.

BillMoyers.com reached out via email to Dr. Gavin Schmidt, a renowned climatologist and the director of the Goddard Institute for Space Studies for his opinion on the plumes observed by the SWERUS crew. He said it’s not yet time for panic.

“The problem with a lot of this research is that we don’t have a long baseline of observations. Therefore when scientists report a new observation, it’s impossible to tell whether it has always been there or whether it is genuinely new,” he wrote. “That goes for these observations in particular.”

He explained that during two periods in the “relatively recent” past — first in the Early Holocene, six to eight thousand years ago, and then in the Eemian, 125,000 years ago — the Arctic was warmer than it is now due to “wobbles in the Earth’s orbit.” Ice core records show that during those warmer periods, the Earth did not release large amounts of methane.

Because the Arctic is not as warm now as it was then, Schmidt wrote, we are not yet at the point where we should expect the Arctic’s frozen methane deposits to melt.

But should today’s human-caused global warming cause the Arctic to warm beyond the high temperatures of the Early Holocene and Eemian periods, the tundra, oceans and ice caps might release methane in amounts never seen before. And that could be quite bad.

As global warming continues, Schmidt wrote, “we will arrive at a point that is completely unprecedented within the last few million years, and at that point, I would be far less sanguine. We are, however, not yet there.”