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.
Its an interesting hypothesis that the increase is caused by methane from permafrost, however do you have any evidence (other than anecdotal observations) for this?
Another hypothesis could be that this is just natural variation in emissions from tropical rainforests, the areas where methane concentration is the highest. Observational evidence also supports this hypothesis.
http://www.hummingbirds.arizona.edu/faculty/saleska/Ecol596L/Readings%5CFrankenberg05_Space.CH4_Science.pdf
What is clear is that bottom up accounting of anthropogenic methane emissions does not explain observations of methane emissions. ie, if anthropogenic methane emissions continue to rise but atmospheric methane emissions do not.
One should therefore not automatically conclude that any rise in methane emissions, historical or present, is likely anthropogenic.
Of course the evidence is far more than anecdotal. A quick search of just this site will show you that methane levels are 100 times higher above the permafrost – this makes a convincing case that the methane is coming from there. That was from 2008. There was also the landmark report from WWF covered in September.
It’s also the point that most of this methane is not anthropogenic in source – otherwise it wouldn’t be a positive feedback or “tipping point”.
Of course the established fact that global warming is anthropogenic means that ultimately this increase in methane is our doing.
Its an interesting hypothesis that the appearance of a curved horizon is caused by the world being spherical, however do you have any evidence (other than anecdotal observations) for this?
C3 is very touchy about “anecdotal evidence” along with gosman. And I suppose that is some cases, anecdotal evidence isn’t all that flash. Maybe the Himalayan Glaciers is a case in point – maybe not. Anyway I was interested to come across this anecdotal piece on disappearing glaciers last night – Published by the “Herald” no less!
http://www.nzherald.co.nz/nz/news/article.cfm?c_id=1&objectid=10614657
Sometimes anecdotal evidence speaks louder than all the scientific evidence you can muster. That is why C3 and gosman don’t want a bar of it because they don’t want to hear!
Anecdotal evidence is what we have to rely on until someone can raise the hard cash to get people and instrumentation out there for solid measurements. Fair enough, it’s not perfect, but if you get anecdotal evidence on an approaching tsunami it doesn’t pay to hang about until you can measure the height of the wave coming up the beach.
That’s not quite what the term means. Are you now going to react to these warnings?
There’s a tsunami coming, quick run!
Last time there was a major tsunami it was straight after sunrise on the full moon … so keep away from the seashore at sunrise on full moon!
Just as zero has no units, neither does it possess a trend, so growth and decline are equally meaningless, even if emotionally appealing.
More importantly, it is a source of amazement that a rise of 7 ppb from about 1750 ppb of atmospheric methane might concern anyone, since it’s an increase of just 0.4%. The most plausible explanation of this increase must be natural variation.
After all, since the decade or so of stability in methane concentrations is unexplained, it’s completely naive to imagine anyone suddenly knows the reasons for this minute growth.
Incidentally, isn’t it odd that so many articles expressing anxiety, even alarm, over this trivial increase of a very minor greenhouse gas manages to discuss it without ever putting the 7 ppb rise into a proper context of the current atmospheric concentration of the stuff?
That’s a long sentence. Nobody mentions the 1750 ppb.
Cheers,
Richard Treadgold.
[Richard: Until you withdraw your shonky “report” on NIWA’s temp record and apologise for smearing the reputations of senior scientists you remain unwelcome here. GR]
How about some other numbers.
750ppb – maximum level over the last 400,000 years.
What of 1,060ppb – the increase since 1750 (and don’t try and tell me this couldn’t possibly be anthropogenic).
More importantly, 20% – the size of methane’s contribution to radiative forcing by gases.
After all, since the levels were less than ~700ppb for the last 400,000 years, it’s not credible to try to explain this kind of increase away with explanations involving natural variation.
Incidentally, isn’t it odd that a person who claims to be able to rebut the work of working NZ scientists would make such a basic error, easily seen as so with a simple check on the “Atmospheric Methane” page on Wikipedia, and a quick look at the relevant section of an IPCC report?
Looking at studies such as this one;
http://www.scichina.com:8080/sciDe/fileup/PDF/02yd1068.pdf
The natural conclusion at this point is that methane has risen and is very likely human caused.
However over the last decade methane levels and atmospheric life times have not increased, you can get that from the IPCC reports as well .
So if the goal of the UNFCCC is to ‘stabilise the concentration of greenhouse gases in the atmosphere that avoids dangerous climate change’, what should the policy be to methane?
I agree with Roger that a 0.4% rise is not cause for concern just yet. Perhaps if the rise is repeated a few more years more caution would be needed. But at present I think, in terms of methane, the UNFCCC’s goal is achieved.
10 years is cherry-picking, and which IPCC report could possibly cover the last 10 years anyway? AR4 is from 2007.
Again you are taking the words too literally; the “stabilization” ultimately refers to the entire ecosystem, not a particular level of gas. If we “stabilize” at a level of gases which is so high that the ice caps are still doomed to melt away in 1,000 years, that is not stable.
If you were to pick any particular metric, it would have to be CO2 ppme, which would include Methane and Nitr* Oxide. Or anthropogenic forcing itself as measured in W/m²
Its a legal document, it should be taken literally.
AR4, ten years, well 1999-2006, so yeah, but anyway,
Changes in methane concentration:
http://www.ipcc.ch/publications_and_data/ar4/wg1/en/figure-2-4.html
Changes in hydroxly radical concentration, driver for methane lifetime;
http://www.ipcc.ch/publications_and_data/ar4/wg1/en/ch2s2-3-5.html
“Just as zero has no units, neither does it possess a trend, so growth and decline are equally meaningless, even if emotionally appealing.”
The only thing meaningless is this statement.
a. Zero certainly has units, the same units as the others on whichever scale it is part of. Are you trying to say 0mm of distance is the same as 0kg of weight?
b. Besides he said near-zero, not zero…
c. A trend is a situation where a measurement deviates from a norm so deviation from many thousands of years of a stable near zero is certainly evidence of a trend. The significance/strength or negation of a trend will be borne out by future measurements.
Yours is a specious argument, Richard, as you nowhere quantify the range of natural variation and beg the question by describing the rising trend as “minute growth” and a “trivial increase of a very minor grrenhouse gas”.
By way of analogy to yourself, suppose that, after years of stable weight of 100 +/- 0.5 kg, your doctor reports that your body mass has increased by 30 grams over the last two years.
A trivial increase of only 0.03 % of your body mass, obviously nothing to be alarmed about – its only that minor gland, your prostate, that has doubled in size…
Are you worried now, Richard?
True, it is a small increase overall, but is it accompanied by an increase of observed (anecdotal) bubbling ponds in what was permafrost? The Canadian permafrost has moved northward, multiple Inuit communities have had to be moved from the coast now that the disappearing pack-ice no longer protects them from erosion, ice truckers have lost 2 months off their season, buildings and oil pipelines in Alaska are collapsing as their foundations melt and Arctic ice-breakers are cruising through multi-year ice that should have ripped their hulls out. I’m worried.
Richard, I have put your latest comment on hold until Gareth returns this evening and can decide what to do about it. So far as I am aware you remain unwelcome on this site, but your appearance caught me by surprise and I’ve let your first comment stand since it has attracted other comments. Please make no further comment in the meantime.
“Just as zero has no units”
Eh?
The box was 1m away and I moved it. It is now 0m away.
Or is it zero feet away? Or zero light years away? Or zero parsecs away?
“Just as zero has no units, neither does it possess a trend, so growth and decline are equally meaningless, even if emotionally appealing.”
In this schoolboy howler, local deniosaur Richard Treadgold exposes a breathtaking ignorance of the rudiments of measurement. He has confused a VALUE (near zero) with a DIMENSION (ppb / year).
The only physical quantities that do not have units, i.e. are “dimensionless”, are, by definition, those formed by the ratios of quantities that have the same dimensions, e.g. the fine structure constant, alpha.
http://en.wikipedia.org/wiki/Dimensionless
As an example, 0 Centigrade is not 0 Fahrenheit or 0 Kelvin. Units matter – just ask NASA, who have lost Mars probes because deacceleration parameters were entered in Imperial units, rather than metric…
http://mars.jpl.nasa.gov/msp98/news/mco990930.html
Back to school, Richard!
Indeed, Rob. He makes another mistake, because the 7ppb increase is per annum, and likely to be sustained over the last three years – making a 21ppb increase over the period, or 1.2% over the baseline he chooses.
(I’ll have more to say on Treadgold and my comment policy later).
Despite what you think of Richard Tredgold his comments posted on this thread are non-confrontational and in-line with the general tone of the blog. I do not see why he should be censored.
I made it clear at the time he released his ludicrous “report” on the NZ temperature record that he would not be welcome here unless and until he issued an apology for attempting to smear NZ scientists. No such apology has been made. I’ll have more to say on this later.
I agree, C3P0, Treadgold’s unjustified attacks on the NZ climate science community appear to arise more from stupidity and ignorance rather than malice.
In the competition to get the most wrong in a single post, he even beats Steve Wrathall – no mean feat…