|Justin Gillis' dead eyes will burn into you until he gets to the truth.|
Man, I should buy a lottery ticket.
While we were working our way through the very excited British accounts of the methyl hydrate threat, and the very phlegmatic (but not entirely convincing) response of Andy Revkin, Justin Gillis came out with a fantastic article on permafrost that is already getting rave reviews. And I thought "I wish Justin Gillis would take on this methane thing."
And in less than a day, Justin Gillis took on the methane thing: "Arctic Methane: Is Catastrophe Imminent?" And Gills' sources, like Revkin's are not overly impressed with the threat of massive methane release:
But the Arctic is, perhaps, something of an exception:
While examples can already be found of warmer ocean currents that are apparently destabilizing such deposits—for example, at this site off Spitsbergen, an island in the Svalbard archipelago in the Arctic—the scientists explained that a pervasive ocean warming sufficient to destabilize a lot of methane hydrates would almost certainly take thousands of years.
And even if that happened, many scientists say that the methane released would largely be consumed in the sea (by bacteria that specialize in eating methane) and would not reach the atmosphere. That is what seems to be happening off Svalbard.
“I think it’s just dead wrong to talk about ‘Arctic Armageddon,’ ” said William S. Reeburgh, an emeritus scientist at the University of California, Irvine, who spent decades studying such matters and says the likely consumption of methane within the ocean should not be underestimated. “Most of this methane is never going to see the atmosphere.”
Nobody regards the case as closed, and more research is necessary, but most of the methane deposits lining the margins of continents would seem to be fairly low on the list of scientific concerns about global warming.
The methane hydrate deposits in the Arctic Ocean may represent a somewhat greater hazard because the Arctic is warming so rapidly. Considerable attention was devoted to a paper published last year that found methane bubbling out across large areas of ocean above the East Siberian Shelf, which has some of the Arctic’s largest methane hydrate deposits.None of these reassurances are entirely satisfying as regards the recent observations, but until we have some clear numbers on those observations and preferably confirmation from another team at the Shelf, or detect a change in the atmospheric burden of methane, it's hard to judge how, if at all, the new observations are going to change how we see the situation under the East Siberian Arctic Shelf.
But that paper did not prove that the methane release was new, much less that it was increasing. Subsequent work by others has in fact suggested that these particular deposits have probably been unstable and slowly breaking down since the end of the last ice age, some 10,000 years ago.
Moreover, the zone from which the methane is escaping appears to represent only a fraction of the total methane beneath the Arctic Ocean. Most methane hydrate is far enough below the sea floor that sediments serve as an insulating layer, limiting how fast heat can spread downward. Again, the most careful calculations seem to put any significant methane release at hundreds or even thousands of years in the future.
As I hope to describe in more detail later this week, methane measurements in the atmosphere are consistent with the picture I just outlined. They do not support the idea that any big new releases of methane are occurring in the Arctic yet, at least not on a sufficient scale to have an overall impact on the planet’s methane burden. So if a methane “time bomb” actually exists in the ocean, as some news stories would have you believe, it seems fairly clear that it hasn’t gone off yet.
Still, there’s no question that some scientists are worried about this issue — less by what we know than what we don’t. Carolyn Ruppel, a geophysicist with the United States Geological Survey, is leading some of the efforts to get better information and especially to map areas off northern Alaska that may contain deposits of methane hydrate. “We need a baseline” against which future changes can be judged, she said.
We await developments (I do feel somewhat better). Meanwhile, a couple of good sources:
Neven's post and thread are superb, as usual.
The Columbia Journalism Review went over the major articles in this mini-methane-stampede.