I haven’t had a chance to read the original paper – I’m getting ready to head out of town and probably won’t get to it until next week, but I just got a press release from U Alaska Fairbanks about a recent paper in this month’s issue of Science that suggests that we’ve got bigger methane problems than we knew about.
From the UAK press release:
The research results, published in the March 5 edition of the journal Science, show that the permafrost under the East Siberian Arctic Shelf, long thought to be an impermeable barrier sealing in methane, is perforated and is leaking large amounts of methane into the atmosphere. Release of even a fraction of the methane stored in the shelf could trigger abrupt climate warming.
“The amount of methane currently coming out of the East Siberian Arctic Shelf is comparable to the amount coming out of the entire world’s oceans,” said Shakhova, a researcher at UAF’s International Arctic Research Center. “Subsea permafrost is losing its ability to be an impermeable cap.”
They found corresponding results in the air directly above the ocean surface. Methane levels were elevated overall and the seascape was dotted with more than 100 hotspots. This, combined with winter expedition results that found methane gas trapped under and in the sea ice, showed the team that the methane was not only being dissolved in the water, it was bubbling out into the atmosphere.
These findings were further confirmed when Shakhova and her colleagues sampled methane levels at higher elevations. Methane levels throughout the Arctic are usually 8 to 10 percent higher than the global baseline. When they flew over the shelf, they found methane at levels another 5 to 10 percent higher than the already elevated arctic levels.
The East Siberian Arctic Shelf, in addition to holding large stores of frozen methane, is more of a concern because it is so shallow. In deep water, methane gas oxidizes into carbon dioxide before it reaches the surface. In the shallows of the East Siberian Arctic Shelf, methane simply doesn’t have enough time to oxidize, which means more of it escapes into the atmosphere. That, combined with the sheer amount of methane in the region, could add a previously uncalculated variable to climate models.
“The release to the atmosphere of only one percent of the methane assumed to be stored in shallow hydrate deposits might alter the current atmospheric burden of methane up to 3 to 4 times,” Shakhova said. “The climatic consequences of this are hard to predict.”
Shakhova, Semiletov and collaborators from 12 institutions in five countries plan to continue their studies in the region, tracking the source of the methane emissions and drilling into the seafloor in an effort to estimate how much methane is stored there.
From the New York Times today:
Natalia Shakhova, a scientist at the university and a leader of the study, said it was too soon to say whether the findings suggest that a dangerous release of methane looms. In a telephone news conference, she said researchers were only beginning to track the movement of this methane into the atmosphere as the undersea permafrost that traps it degrades.
But climate experts familiar with the new research, reported in Friday’s issue of the journal Science, said that even though it does not suggest imminent climate catastrophe, it is important because of methane’s role as a greenhouse gas. Although carbon dioxide is a far more abundant and persistent in the atmosphere, ton for ton atmospheric methane traps at least 25 times as much heat.
The paper is behind a paywall for those not in the reporting business, but I will link more as more comes available. If correct, this is not good news – the prior assumption was that increased levels of methane in the arctic were linked primarily to methane bubbling out of freshwater areas – but there’s much more methane here to release.
Here’s an NSF piece on the potential role of methane in abrupt climate change. I should emphasize here that we have no idea this methane release could cause something similar to occur, but this strikes me as a compelling case for the precautionary principle – precisely because we have no idea.
An abrupt release of methane, a powerful greenhouse gas, from ice sheets that extended to Earth’s low latitudes some 635 million years ago caused a dramatic shift in climate, scientists funded by the National Science Foundation (NSF) report in this week’s issue of the journal Nature.
The shift triggered events that resulted in global warming and an ending of the last “snowball” ice age.
The researchers believe that the methane was released gradually at first and then very quickly from clathrates–methane ice that forms and stabilizes beneath ice sheets.
When the ice sheets became unstable, they collapsed, releasing pressure on the clathrates. The clathrates then began to de-gas.
“Our findings document an abrupt and catastrophic global warming that led from a very cold, seemingly stable climate state to a very warm, also stable, climate state–with no pause in between,” said geologist Martin Kennedy of the University of California at Riverside (UCR), who led the research team.
“What we now need to know is the sensitivity of the trigger,” he said. “How much forcing does it take to move from one stable state to the other–and are we approaching something like that today with current carbon dioxide warming?”
Allow me to speak for all of humanity when I say…crap.