Thursday, 8 November 2007

Hockey Stick Argument Summarised

I still get a few climate loons defending the accuracy of the IPCC's iconic, and now infamous, Hockey Stick with one recent know-nothing trying to claim that it actually shows the MWP and LIA.

Steve McIntyre summarises the facts around the statistical demolition of the Hockey Stick, which has led to its derogation by the IPCC and sidelining of its authors - Mann, Bradley and Hughes.
In recent discussion of the Weblog 2007 Awards, several commenters at other blogs have argued that our criticisms of the Mannian parlor tricks have been “thoroughly refuted and discarded by climatologists, published in a credible journal”; that “other professionals in the field who also have “looked in great detail at the problem at hand” and have come to the conclusion that rather than McIntyre’s findings being “valid and relevant”, they instead have found them to be “without statistical and climatological merit”; that CA “fluffed on the whole hockey stick thing”. See for example here

Omitted in these references are the fact that the people described as “climatologists published in a credible journal” or “professionals in the field” are none other than Wahl and Ammann, serial coauthors with Michael Mann, students of Mann, who are not independent of the controversy. Indeed, they largely use (without citation or attribution or even acknowledgment to Michael Mann) arguments originally published at realclimate (and already responded to in MM 2005b(EE). Aside from their lack of independence, neither Ammann nor Wahl qualify as statistical authorities. Ammann did his undergraduate work in geology; Wahl in divinity. While this does not exclude them from having potential insight in the matter, it is evidence that one should not necessarily expect a sure grasp of mathematical and statistical issues and that their conclusions cannot be relied upon uncritically, even if Stephen Schneider accepted their article.

Readers interested in a third party view of the matter are far better off consulting the North Report, the Wegman report, (particularly) Wegman’s Reply to Questions and Richard Smith’s account of the 2006 American Statistical Association session. All of these individuals are vastly more eminent than Ammann and Wahl. Wegman, in particular, has been Chair of the National Academy of Sciences Committee on Theoretical and Applied Statistics and is a legitimate statistical expert. His comments on the Wahl and Ammann preprint are very acute and have not received appropriate consideration.
Read the rest. It's pretty interesting to understand the lack of true peer review undertaken in climate science.

(Nothing Follows)


Anonymous said...

Are you blind or can you really not see that the famous chart clearly shows that 1000-1450 was warmer than 1450-1850? The magnitude of the difference is clearly not what your faith-based position tells you it should be, but the features are obvious to all except the very stupid. Now, what is your evidence that at some point in the past 10,000 years, global temperatures have been significantly higher than those we see today?

And why lie? As you always seem to, you start with a blatant untruth. its derogation by the IPCC - have you looked at figure 6.10 in the 4AR? Does it look rather familiar?

Anonymous said...

neither Ammann nor Wahl qualify as statistical authorities. Ammann did his undergraduate work in geology; Wahl in divinity - now isn't that rich coming from a mining executive and his economist friend, who think that they are qualified as climatological authorities!

Jack Lacton said...

Have a look at the graph at and you'll see the Hockey Stick vs what used to be the norm and is still being proven by other methodologies including ice core analysis.

Please look up the meaning of the word 'derogation'. The Hockey Stick used to be figure 1.0 and now it's 6.1.

McIntyre is a statistician. There are very few people arguing for the pro- side that understand statistics including the so-called Hockey Team.

Anonymous said...

Bad choice of article to link to - did you notice that the two graphs have different scales, and that the bottom graph claims to be European temperatures and not global temperatures? Remember, the phenomenon we're talking about is global warming, not European warming.

To claim that the numbering of the figures is somehow a reflection of their importance is the most ridiculous argument I've heard in any debate for a very long time.

Is he a statistician? According to his own website For McIntyre, undertaking this project has required an unpaid leave of absence from his career in mineral exploration financing.

Anonymous said...

Oh, and by the way, you're making stuff up again. The 'hockey stick' was figure 2.20 in the 2001 report. But I'll emphasise again that you'd have to be truly desperate for arguments to claim that the figure numbering means anything at all about the significance of the figures.

Jack Lacton said...

Seriously. How thick are the warmanistas? To not even know that Steve McIntyre is a statistician (and winner of multiple mathematics awards in his youth) shows that they've only ever looked at one side of the argument.

These people are beyond reason.

Anonymous said...

What's a warmanista? And can you give a link to evidence of McIntyre's qualifications? Why does he say his career was in mineral exploration financing, if it is actually in statistics?

Anonymous said...

Well, anonymous, it's entirely possible that those of you who worship without question at the altar in the Church of Global Warming will never wonder if the gospel of the IPCC is inerrant. But you could take a little time to examine the issue if intellectual honesty has any value.

Science is about proof. Not consensus. I don't know if there is or is not an unnatural warming event. But I can say with certainty that you cannot say there is.

There is a far more impressive correlation between temperature and solar activity than with CO2.

You might look through some of these.

Your rather brown-shirted approach to calling skeptics "liars" and "stupid" are just the kind of activities that make folks like me even more skeptical. Real science doesn't rely on those kinds of polemics. Real science just sits there quietly and speaks its own truth.

The debate isn't over. It hasn't even yet started.



Jack Lacton said...

Good work, Krumhorn.

Anonymous said...

Sadly, Krumhorn, it looks like you haven't studied the science. There is a far more impressive correlation between temperature and solar activity than with CO2 - sadly, no. Solar activity, by any measure, has been declining since 1985 at the latest. And yet temperatures have gone up significantly since then.

Try reading actual science in peer-reviewed journals. Your web pages are riven with errors, really basic errors. Science does not support your beliefs.

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