Desmog, without carrying out any due diligence of their own, spread false information derived from Brian Angliss here. Angliss alleged that I had “made a number of claims that are not supported by the published record”.
His second such allegation arose from comments in a CA post on the Commons Select Committeee here. Towards the end of the post, I was commenting on the following finding (para 66) of the Commons Select Committee:
In our view, it ["hide the decline"] was shorthand for the practice of discarding data known to be erroneous. We expect that this is a matter the Scientific Appraisal Panel will address.
To which I replied:
their suggestion that Jones and others were doing nothing more than “discarding data known to be erroneous” is simply absurd. There was no testimony to the Committee (nor has it ever been suggested) that the tree ring data was measured incorrectly or that the data was “erroneous” – the data is what it is. The tree ring data goes down instead of up – but that doesn’t make it “erroneous”. It only means that the data is a bad proxy – something that was concealed from IPCC readers.
That statement is 100% correct and support. Nonetheless, Angliss alleges fault as follows:
McIntyre also claimed that
[t]he tree ring data goes down instead of up – but that doesn’t make it “erroneous”. It only means that the data is a bad proxy.
This might be true if the data supported it, but the data clearly doesn’t..
Reading the above at face value, Angliss seems to be saying that the Briffa data doesn’t go down. But that isn’t true. For reference, here is the Briffa data (without smoothing) included the deleted portion (never available digitally prior to Climategate.) The Briffa reconstruction obviously goes down in the last half of the 20th century. Otherwise they wouldn’t have bothered trying to hide the decline in the Briffa data.
Angliss goes on:
First, the tree rings that diverge from the instrumental record are not all tree ring datasets, but rather a subset of tree ring datasets. In particular, the divergence problem applies to the Briffa 2000 dataset taken from trees close to the Arctic Circle. Other tree ring datasets don’t show the same divergence issue, as summarized in Cook et al 2004.
I made a detailed analysis of the Cook network in March 2006 here – a post in which I displayed (and commented on) the same Cook graphic in Angliss’ post – one Angliss accuses me for not considering.
Cook et al 2004 considered a small network of only 14 sites, two of which were strip bark (foxtail) sites. In comparison, the Schweingruber network studied by Briffa had about 381 sites. While the Briffa network is, in a trivial sense, only a “subset” of all tree ring sites, it is a very large sample – and the sites had been selected ex ante as temperature limited. In contrast, the Cook et al 2004 network was a far smaller subset. In addition, the “southern” group in the Cook et al network, which are supposed to allay concerns about divergence, consisted of only five sites, two of which were strip bark sites in arid locations. (The NAS panel said that strip bark chronologies should be “avoided” in temperature reconstructions.) Cook et al 2004 did not resolve the divergence problem. It was a weak statistical analysis on a small data set that left the original problem unresolved.
In a 2007 AGU session discussed at CA here, I observed that the “young dendros” were not content with attempts to simply pretend that the problem didn’t exist and regarded the divergence problem as a serious challenge to their field (Cook sat in the audience rather stonily.)
The most recent analysis of the divergence problem (Lloyd and Bunn 2009 Env Res Letters), by two excellent dendros both of whom I’ve corresponded with amicably in the past, doesn’t even cite Cook et al 2004 in their survey of serious efforts to resolve the divergence problem. Nonetheless, Angliss accused me and Fuller as follows:
McIntyre and Fuller should both be aware enough of the progress made in dendroclimatology (deducing past climate from tree rings) since 2001 to not make erroneous claims.
Nor did I make erroneous claims.
The Commons Committee had stated that “[hide the decline] was shorthand for the practice of discarding data known to be erroneous.” I observed (correctly) that there was no evidence to the Committee that the tree ring data had been measured wrong – which would be required to discard the data as “erroneous”. This comment remains both correct and unrebutted.
Rather than deal with what I had actually written – and which was irrefutable- Angliss’ trick (“a good way to deal with a problem” [Gavin Schmidt]) was to divert the discussion into an entirely different question that was not at issue in my comment on the Commons Committee: whether Cook et al 2004 had resolved the divergence problem. Even if Cook et al had done so, it wouldn’t show that my original comment was “erroneous” or justify these particular claims against me by Angliss and Desmog, but, in any event, Cook et al 2004 didn’t resolve the divergence problem. It was a weak statistical analysis on a small network; the divergence problem remains outstanding.
Update 1.55 pm: there are other untrue statements in Angliss’ post, including his allegation [see comments] that my short comment about the Commons Committee was somehow refuted by Mann et al 2008, an article that I “should” have known about. Obviously I know about Mann et al 2008. The idea that it refutes the above short comment about the Commons Committee is absurd. I’ll pick this spitball off the wall in due course.