Huge releases of arctic methane

Methane is a greenhouse gas 20 times more potent than carbon dioxide.

At the American Geophysical Union Meeting in San Francisco, Dr Semiletov announced he’d found an unprecedented amount of methane bubbling up from the East Siberian Arctic Shelf (which he’s been monitoring for almost 20 years).  Which means methane is also likely bubbling up elsewhere in the Canadian arctic shelf, Greenland, etc.

“Earlier we found torch-like structures like this but they were only tens of meters in diameter. This is the first time that we’ve found continuous, powerful and impressive seeping structures, more than 1,000 meters in diameter. It’s amazing,” says Dr Semiletov. “I was most impressed by the sheer scale and high density of the plumes. Over a relatively small area we found more than 100, but over a wider area there should be thousands of them. Some plumes were a kilometer or more wide and the emissions went directly into the atmosphere – the concentration was a hundred times higher than normal.”

American scientists estimate that there are hundreds of millions of tons of methane gas locked beneath the Arctic permafrost. When the Arctic sea-ice vanishes in summer, resulting in rapidly rising temperatures across the entire Arctic, the trapped methane could be suddenly released into the atmosphere leading to rapid and severe climate change.

Methane from Permafrost melting

Experts have long known that northern lands were a storehouse of frozen carbon, locked up in the form of leaves, roots and other organic matter trapped in icy soil — a mix that, when thawed, can produce methane and carbon dioxide, gases that trap heat and warm the planet. But they have been stunned in recent years to realize just how much organic debris is there.

A recent estimate suggests that the perennially frozen ground known as permafrost, which underlies nearly a quarter of the Northern Hemisphere, contains twice as much carbon as the entire atmosphere.

Temperatures are warming across much of that region, primarily, scientists believe, because of the rapid human release of greenhouse gases. Permafrost is warming, too. Some has already thawed, and other signs are emerging that the frozen carbon may be becoming unstable.

“It’s like broccoli in your freezer,” said Kevin Schaefer, a scientist at the National Snow and Ice Data Center in Boulder, Colo. “As long as the broccoli stays in the freezer, it’s going to be O.K. But once you take it out of the freezer and put it in the fridge, it will thaw out and eventually decay.

If a substantial amount of the carbon should enter the atmosphere, it would intensify the planetary warming. An especially worrisome possibility is that a significant proportion will emerge not as carbon dioxide, the gas that usually forms when organic material breaks down, but as methane, produced when the breakdown occurs in lakes or wetlands. Methane is especially potent at trapping the sun’s heat, and the potential for large new methane emissions in the Arctic is one of the biggest wild cards in climate science.

41 permafrost scientists estimate that if human fossil-fuel burning remains high and the planet warms sharply, the gases from permafrost could eventually equal 35% of today’s annual human emissions.

the chief worry is not that the carbon in the permafrost will break down quickly — typical estimates say that will take more than a century, perhaps several — but that once the decomposition starts, it will be impossible to stop.

“Even if it’s 5 or 10 percent of today’s emissions, it’s exceptionally worrying, and 30 percent is humongous,” said Josep G. Canadell, a scientist in Australia who runs a global program to monitor greenhouse gases. “It will be a chronic source of emissions that will last hundreds of years.

A troubling trend has emerged recently: Wildfires are increasing across much of the north, and early research suggests that extensive burning could lead to a more rapid thaw of permafrost.

Steve Connor. 14 Dec 2011. Rapid rise in Arctic methane shocks scientists.  New Zealand Herald.

Justin Gillis. 16 Dec 2011. As Permafrost Thaws, Scientists Study the Risks. New York Times.

Michelle C. Mack,et al. Carbon loss from an unprecedented Arctic tundra wildfire. Nature, 2011; 475 (7357): 489

Charles Moffat. 13 Dec 13 201.  Deadly Greenhouse Gas bubbling up in Russian Arctic Lillith News

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