Well, with a headline like that you know I’m talking about denialist nonsense, and yes its WUWT again. What they are foaming at the mouth about is Jarvis Cocker: the iceman cometh but not the article, rather a factoid at the end:
Of the Arctic sea ice, 75% has been lost over the past 30 years. Last year saw sea-ice levels plummet to the second-lowest since records began. It is estimated that the North Pole could be ice-free in the summer within the next 10-20 years
Understanding this fairly simple piece of text proves to be beyond the Minds over there. 75% is a lot, and ice area or extent hasn’t declined by that much, so the obvious variable to look at is volume, which has declined more steeply. And indeed, if you look at the PIOMAS-based Arctic Sea Ice Volume Anomaly, version 2 you’ll discover that the September minimum has indeed declined by the reported amount.
So: how is it possible to be so stupid as to not guess this yourself? If you start from the bad-faith position that the Grauniad as lying, then you probably won’t even look. And if you’re so used to denying the ice change, then you’ll then further mislead yourself and your readers by deliberately looking at the change in annual extent rather than the September minimum, which is the one that people are far more interested in.
The very second commentator manages to guess right: I think the argument is about sea ice volume rather than area/extent but even with this clue AW still fails, replying The original article… does not contain any discussion of ice volume. I double checked. But by this point I think he has realised he is lying, because of course the original article doesn’t specify extent, or area either. Indeed the original article is unclear; but when there are several interpretations, one of which agrees exactly with the numbers, it doesn’t take much sense to realise which was the right one. Commentator number three finds the second flaw in AW’s stuff: that he has deliberately used annual rather than minimum. But neither 2 nor 3 has the wit or industry to find the actual numbers from PIOMAS.
Sadly, the usually sensible Nick Stokes manages to find the correct source for the numbers but then (mislead by the contrived lead-in of AW’s post?) fails to read them properly.
A little while later (after a pile of content-free Grauniad-bashing) JohnB finds the right answer and supports it with number from thinkprogress. AW doesn’t like this and in reply says some spurious nonsense and one plausible thing, viz quoting Julia Slingo: She also said that suggestions the volume of sea ice had already declined by 75% already were not credible. “We know there is something [happening on the thinning of sea ice] but it’s not as dramatic as those numbers suggest.” We need to pause here for a moment to contemplate the irony of AW taking as gospel the words of the UK Met Office’s chief scientist. This oddity can be explained in this way: she is saying something he wants to hear. However, AW still isn’t thinking straight: the Grauniad can only be reporting what the numbers say, not the One True Reality that inhabits JS’s mind. So when AW says “Slingo said the 75% loss for volume isn’t supported” he is, if he pauses for a moment to think, already in possession of the correct answer.
So, by that point in the comment thread it has clear to anyone who is reading that, yes, the Grauniad was correct – or, if you prefer the worst interpretation, that they were correctly reporting, in broad-brush terms, the numbers that are generally bandied about. That doesn’t stop the commentators still pushing “Someone needs to sue the paper for misrepresentation” and so on. Just a little later Steve from Rockwood asks “In discussing ice volume, how do they reliably estimate volume from the satellite data?” No-one there has any answer (which is odd, considering that they like to think they have a clue), but anyway, if SfR was actually interested he would have followed one of the links already provided.
And eventually, all doubt is removed: Phil Clarke finds the actual source from Greenpeace which the Grauniad has used, and yes indeed it is talking about volume, and the source is PIOMASS. AW gets really snotty in reply to that; pointing out the actual referenced source of the numbers in question has become, in AW’s words, “wasting my and everyone else’s valuable time with your diversions”.
The Slingo question
As noted, AW is heavily reliant on Slingo as his authority that ice volume has not declined by 75% (incidentally, I too wouldn’t assert that it has declined by X, and nor would the PIOMASS people, with certainty, I’d guess). But as a best-guess estimate its not implausible. The source for the JS quote is The Grauniad but the original is UNCORRECTED TRANSCRIPT OF ORAL EVIDENCE ENVIRONMENTAL AUDIT COMMITTEE PROTECTING THE ARCTIC WEDNESDAY 14 MARCH 2012 who are clearly very shouty people. The Graun’s quote from her is odd. They have her say:
* “We know there is something [happening on the thinning of sea ice] but it’s not as dramatic as those numbers suggest.”
instead of what she actually said:
* We know there is some thinning but it is not as dramatic as those numbers would suggest.
I can’t see why they prefer their longer and less clear and non-direct-quote version. But on: what question was JS actually answering with those words?
Q118 Chair: One lot of evidence that we had suggested that the volume of ice had already declined by 75%, and that further decreases may cause an immediate collapse of ice cover. Would you recognise that? Would you give credence to that?
Professor Slingo: No, I wouldn’t. We don’t know what the thickness of ice is across the whole Arctic with any confidence. We know that the sea ice extent has declined annually by 4% per decade, and in summer, yes that the sea ice is declining at a faster rate of 12% per decade. You also have to understand that it recovers pretty well as we go back into winter, so the 4% per decade annually is still there. We know there is some thinning but it is not as dramatic as those numbers would suggest.
So, this is ambiguous. She may just be reacting to the “further decreases may cause an immediate collapse of ice cover”. Although in answer to Q117 she has just said “We run quite a sophisticated sea ice model that includes the volume of ice, and it is fair to say, yes, there is a decline in the volume of ice” which I find surprising. If she is on top of a UKMO programme that parallels PIOMASS, why isn’t she quoting any numbers from it? That would be the natural thing to do. I’m not aware of UKMO/ Hadley “observational modelling” of sea ice like PIOMASS; they have HadISST, but that is area/extent type stuff. My suspicion is that JS has confused the climate-type GCM sea ice model with what PIOMASS are doing. Though if anyone has any better ideas, I’ll be interested to hear them.
JS isn’t a sea-ice modeller; I wouldn’t give any particular credence to what she says, at least insofar as it could be considered an interpretation of the PIOMAS 75% figure.
Finally, Scott notices the other anomaly, that “If they were talking about volume, then last year was the LOWEST, not second lowest. Thus, if they’re talking about modeled volume (at the summer minimum), then the second sentence is wrong”. This is (at last) a fair point (and one that AW is happy to sieze upon, since his existing “rebuttal” of its-not-volume is so unconvincing). The answer I can think of is that by the standards of newspaper journalism, swapping from volume in one sentence to extent in the next is hardly a big leap, indeed such a tiny one that they wouldn’t even notice it.
It is estimated that the North Pole could be ice-free in the summer within the next 10-20 years
I suppose we’re left with that. What does it mean? Hard to know. If you meant, literally, just the North Pole then maybe its plausible. If “North Pole” is a proxy for the whole sea ice cover, then I’m dubious. But you know that already.
In this case, if you strip out the mood-music from the peanut gallery and look only at the comments where people have made at least a small attempt to think, the crowd doesn’t do too badly, considering that they have all been put off the true scent by the trail AW has tried to lead. Dave, a True believer, even gently criticises WUWT for not writing a very good response to the Grauniad. Mat L argues
C’mon Anthony, you lose credibility when you start comparing sea ice extent with a volume metric and saying they don’t match. Fair enough if you missed this when writing the article, but now it has been pointed out to you, it’s disingenuous not to update your post/ graph.
[Update: I'm banned at WUWT. I've had some fun tweaking AW's source for this nonsense, though -see the comments there. Back at WUWT, PaulB is doing a good bulldog on AW. I am curious to see how long before he gets stomped on - W]
* Nick Stokes has a nice set of plots of the PIOMAS data by year, etc., and with his nice “anomaly with trend removed”.