Tag: methane

Methane rise continues

More cautionary news on rising methane levels is reported in yesterday’s Independent. Two leading experts on CH4in the atmosphere, Euan Nisbet and Ed Dlugokencky, were due to reveal at a conference that, after a decade of near-zero growth, “globally averaged atmospheric methane increased by [approximately] 7ppb (parts per billion) per year during 2007 and 2008.” They consider it likely that 2009 will have shown the same rising trend, since the figures for the first half of the year showed a 7 ppb rise on the 2008 level.

They are properly cautious about the rises and comment that they may just be a couple of years of high growth which may drop back to what it was.  But they stress the importance of understanding the causes of the rises, because of the potential for increased CH4 emissions from strong positive climate feedbacks in the Arctic where there are unstable stores of carbon in permafrost. Permafrost melt carries the potential for methane release.

If there is a feedback mechanism at work it’s bad news as the Independent makes clear in terms that its readers can understand:

“Many climate scientists think that frozen Arctic tundra… is a ticking time bomb in terms of global warming, because it holds vast amounts of methane, an immensely potent greenhouse gas. Over thousands of years the methane has accumulated under the ground at northern latitudes all around the world, and has effectively been taken out of circulation by the permafrost acting as an impermeable lid. But as the permafrost begins to melt in rising temperatures, the lid may open – with potentially catastrophic results”.

This is not alarmism on the part of the Independent. The scientists involved in reporting the rises are careful and restrained in their statements.  We may hope that the increases turn out not to be significant in terms of feedbacks under way.  But it is a sober reminder of how quickly things may change if natural feedbacks kick in and amplify the warming already caused by our human activity.  See Gareth’s earlier post on methane hydrates in the Arctic.

Incidentally, it was good to see a newspaper competently and thoroughly reporting climate change science news.  It can happen, and when it does it’s a different world from the ignorant and careless journalism that has been so apparent recently in relation to the UEA emails and the IPCC report.  Rationality and proportion marked an excellent piece of science reporting.

Tipping and other points

During the Copenhagen kerfuffle a lot of interesting stuff hit the web: here’s something that deserves a bit more air – a Proceedings of the National Academy of Science (PNAS) special issue on tipping elements in the earth system, edited by John Schellnhuber, the director of the Potsdam Institute for Climate Impact Research in Germany.

Tipping elements (or points, as Malcolm Gladwell would have them) are changes that once started take on a life of their own, and can’t easily be returned to their original state. In the climate system that might be the rapid loss of an ice sheet in a few decades or hundreds of years, while regrowing it might take many thousands. The PNAS special issue deals with nine: dust production in the Bodélé Depression in Chad, ENSO, Arctic sea ice and ice sheets, the Atlantic Meridional Overturning Circulation, deep ocean hydrates (not shallow sea bed, Siberian methane) — David Archer dubs them a “slow tipping point”, the Amazon rainforest (no “Amazongate” here, just a confirmation that concern is justified), monsoons, oceans, and policy responses to the climate challenge. And the best thing is that all the articles are available online, free (click on the link above). Schellnhuber contributes an introduction, and the Potsdam press release also provides a good overview. For some introductory thoughts, check out Tim Lenton’s discussion here.

Another recent example of a real tipping point is the Pine Island Glacier in West Antarctica. Recent modelling suggests that the glacier’s grounding line retreated beyond a ridge in 1996, and is now free to retreat by several hundred kilometres inland. This could happen in a hundred years and result in the loss of half of the ice in the glacier — enough to raise sea level by 24cm. New Scientist reports:

Observations already show that the model severely underestimates the rate at which PIG’s grounding line is retreating, says Katz. “Ours is a simple model of an ice sheet that neglects some important physics,” says Katz. “The take-home message is that we should be concerned about tipping points in West Antarctica and we should do a lot more work to investigate,” he says.

Amen to that.

Oops, he did it again

It pays to beware of leaving hostages to fortune: saying or doing something that might cause you some embarrassment in the future. There’s a very fine example in this recent blog post by Ian Wishart, titled “Top 10 global warming myths exposed“. It takes the form of a piece Wishart has submitted to the Coromandel Chronicle, taking exception to a column by Thomas Everth [PDF]. He begins:

In a blatant effort to mislead and scare your readers, Green blogger Thomas Everth makes more errors in the first 200 words of his recent global warming diatribe than I have made in my last three books totalling around 400,000 words.

As hostages go, that’s pretty impressive. Wishart proceeds to find fault with ten of Everth’s opening points, but does he make a few mistakes of his own in the process? I’m going to take a long, hard look: is that hostage feeling lucky?

Continue reading “Oops, he did it again”

Siberian Shelf methane increased in 2009

arcticmethane.jpgMethane release from the permafrost and hydrates under the East Siberian Shelf in autumn 2009 was the highest ever recorded, the leader of the International Siberian Shelf Study (ISSS), Igor Semiletov, has told the BBC. The results of last autumn’s research cruises are being prepared for publication in the near future. The BBC also quotes Semiletov’s colleague Prof Orjan Gustafsson from Stockholm University:

He said that methane measured in the atmosphere around the region is 100 times higher than normal background levels, and in some cases 1,000 times higher.

Gustaffson went on to say that “so far” there was no cause for alarm, and stressed the need for further study. Sounds like a scientist… For background, check out last year’s WWF Arctic report (I discussed the chapter on Arctic methane here), and my posts on the 2008 ISSS expeditions (one, two). Looks like the methane release is confirmed as chronic, but not yet (if we’re lucky) acute.

Methane rise confirmed

The recent global uptick in atmospheric methane levels is confirmed today by new figures from NIWA’s Baring Head station, near Wellington. Southern hemisphere methane rose by 0.7% over the two years 2007-2008. The video above, narrated by tropospheric chemist Katja Riedel gives an inside view of what goes on in and above the Baring Head lighthouse — well worth a view. The increase comes after a three year period when levels had appeared to stabilise, as NIWA’s graph shows:

BHmethaneAug2009.gif

From NIWA’s press release:

This […] accounts for more than half of the growth observed over the ten years 1999–2008 (1.2%). Methane is the second most important contributor to global warming behind carbon dioxide, though its abundance in the atmosphere is far lower. Additional methane traps twenty one times more heat over 100 years than the same mass of carbon dioxide (CO2 ).

“The evidence we have shows that methane in the atmosphere is now more than double what it ever was during the 800,000 years before 1700AD” says NIWA Principal Scientist, Dr Keith Lassey. This is based on analyses of ancient air trapped in polar ice that has been extracted and dated.

The new figures confirm the global picture compiled by NOAA in the US. The increase is thought to be related to a return to wetter conditions in the tropics after a relatively dry period from 1999–2006 and warming in the Arctic. There’s a lot more background information on NIWA’s news page.