Climate change deniers’ tawdry manipulation of “hockey sticks”

Warning: This post abounds in “hockey sticks.”

Poneke’s recent blog post, 13 years of Climategate emails show tawdry manipulation of science by a powerful cabal at the heart of the global warming campaign, precipitated a lively discussion. Well, perhaps “discussion” is too kind because it was dominated by extreme deniers.

Now, I don’t want to label people unjustly. I respect those who are sceptical of the IPCC climate change conclusions, but are willing to stick with the science in discussing them. I reserve the term “deniers” for those irrational souls who grab at anything they can (cold days, snow, 1998 temperatures, IPCC mistake on Himalyan glaciers, etc., etc.). No interest in the science – just in using “sciencey” claims to advance their preconceived conclusions.

But my point in this post is to deal with one of Poneke’s claims which is demonstratively untrue.

The “Gish gallop”

A tactic of deniers, also common to evolution deniers, which dominated their approach in the comments on Poneke’s post is the “Gish Gallop.” They fire out arguments like a machine gun, one fabrication after another – moving quickly on before any particular fabrication can be examined and refuted. I guess it’s what you do if all you rely on is fabrications.

Well, taking George Monbiot‘s advice (stick with the first fabrication, concentrate on that and don’t be diverted by new fabrications) I thought I would show Poneke he is wrong in his claims about “Mann’s now infamous “hockey stick” graph.” He calls it “the ‘hockey stick’ graph the IPCC has quietly dropped from its reports” and also claims “it was totally discredited and dropped from subsequent IPCC reports.”Mann’s data on temperature changes over time were included in the 2001 reports and Poneke claims they were not in the 2007 IPCC reports.

I challenged Poneke several times on this and he repeated “Mann’s hockey stick has been thoroughly discredited and the IPCC has dropped it from its reports, just as I state.”

The “infamous, discredited” hockey stick

That’s the problem with quoting yourself as the authority – you can be wrong and not know it. It’s always best to check. If Poneke had done so he would have found this figure below in the 2007 reports. The original data from Mann (MBH 1999) is included with, of course, more recent data. Here is the reference for Poneke, or anyone else doubting my claim – Figure 6.10, page 467,  Chapter 6: Palaeoclimate,The Fourth Assessment Report (AR4), WG I The Physical Science Basis. Mind you, I gave this information to Poneke in a comment to his post – but it was deleted!

Poneke’s cavalier attitude to facts like this should surely leave any claims to journalistic integrity in tatters.

And far from this work being “thoroughly discredited” or abandoned, it has been expanded with more, recent, data. The graph below is from Mann’s 2008 paper (Proxy-based reconstructions of hemispheric and global surface temperature variations over the past two millennia).

National research Council report vindicates Mann

In this paper Mann was responding to suggestions made by the National Research Council in its report  Surface Temperature Reconstructions for the Last 2,000 Years. This thorough and rigorous investigation formed part of US House of Representatives Committee hearings on Mann’s “hockey stick” figure arising from criticisms made by climate change sceptics. It is very authoritative.

The report basically supported Mann’s findings:

“The basic conclusion of Mann et al. (1998, 1999) was that the late 20th century warmth in the Northern Hemisphere was unprecedented during at least the last 1,000 years. This conclusion has subsequently been supported by an array of evidence that includes both additional large-scale surface temperature reconstructions and pronounced changes in a variety of local proxy indicators, such as melting on ice caps and the retreat of glaciers around the world, which in many cases appear to be unprecedented during at least the last 2,000 years.”

In fact the NRC produced their own “hockey stick” in the report (see figure below):

Lord Monckton’s lies about the “hockey Stick”

Poneke’s false assertions on the “hockey stick” graph are, unfortunately, very common. It’s one bit of mudslinging that has found purchase with most deniers repeating the lie. Even some sceptics believe the story.

Lord Mockton has been a prolific propagator of this lie. He even appears in the infamous “climategate” emails saying of the “hockey stick”: “the US National Academy of Sciences has described as having “a validation skill not significantly different from zero”. In plain English, this means the graph was rubbish.”

Problem is – search through the NRC report and you just won’t find those words (“a validation skill not significantly different from zero”). Nevertheless this allegation has been repeated innumerable numbers of times in conservative newspapers and websites. Some of these also claim (as does Poenke) that the IPCC had abandoned the data (see for example the policy Brief from the Commonwealth foundation – Climate & Penn State – demanding a McCarthyist-style investigation of Mann). But even Mockton acknowledges that “the UN continues to use the defective graph.”

I guess it just makes a good story so these conservative sources tack it on. As does Poneke.

But, again, where is the journalistic integrity it that?

Footnote: Poneke is continuing his campaign against facts by petulantly demanding that scientists should not speak out on climate change! (see Taxpayer-funded Science Media Centre gets a curious ratings boost from global warming).

Why – because they are biased!

Well, I guess they are – after all they are obliged to deal with facts – not the fairy tales of witch-hunting deniers and conspiracy theorists.

Mind you, he makes sure these facts don’t get into his blog comments. Mine certainly haven’t lately.

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See also:
Journalist thinks world climate-science publications are controlled by cabal
Analysis of stolen CRU emails by NZ blogger shows tawdry manipulation of facts – Poneke’s credibility now in tatters — Hot Topic