Wednesday, June 23, 2010

More scientists weigh in

I'm beginning to think the jig is up for global warming theory. Many scientists have stayed out of the controversy; they don't want to be political, they don't want to be branded as creationists, and they assumed there were people in charge of climate science who were both honest and competent.

That is changing at least a bit. Some of them are looking more closely--in the manner of someone picking up a dirty diaper. Judith Curry, who is known as a climate scientist, not really sceptical about the main elements of the theory, but concerned about evidence of shoddy practices by climate scientists, has "laid down the gauntlet," challenging defenders of the hockey stick and/or the IPCC to read Montford's book, The Hockey Stick Illusion.

One member of Lord Oxburgh's review panel to establish if the CRU was dishonest was Michael Kelly, Professor of Electronics at Cambridge. He came to the work, as it were, for the first time. He read through papers by Briffa and Jones. First time through Briffa:

My overriding impression that this is a continuing and valiant attempt via a variety of statistical methods to find possible signals in very noisy and patchy data when several confounding factors may be at play in varying ways throughout the data. It would take an expert in statistics to comment on the appropriateness of the various techniques as they are used. The descriptions are couched within an internal language of dendrochronology, and require some patience to try and understand. There is no evidence, as far as I am concerned, of anything other than a straightforward scientific exercise within the confines described above. The papers are full of suitable qualifications about the limitations of the data and the strength of the inferences to be drawn from them. I find no evidence of blatant mal-practice. That is not to say that, working within the current paradigm, choices of data and analysis approach might be made in order to strain to get more out of the data than a dispassionate analysis might permit.


So Briffa does not appear to be outright dishonest--which was apparently the main question facing the Oxburgh group. More and more problems appear: "The line between positive conclusions and the null hypothesis is very fine in my book." Kelly begins to wonder if Briffa has actually proved anything at all.

First time through Jones:

"There is plenty of openness about the limitations of the data. There is no evidence of overt scientific malpractice. That is not to absolve the authors of conscious or unconscious bias in making all the choices referred to above."

Again, no evidence of the most direct dishonesty. "In neither of these papers is there any overt malpractice, but one can't eliminate the possibility of conscious or unconscious bias in the choices of data. I just do wonder if a different hypothesis was being tested whether the same approach could give a very different answer." Kelly is growing uneasy.

Even in the first reading he says he is appalled at the suggestion that data must fit the model, instead of the other way around. The second reading shows more questions, and after the second reading he has questions for both Jones and Briffa.

For Jones:

(7) Given that the outputs of your work are being used to promote the largest revolution mankind has ever contemplated, do you have any sense of the extent to which the quality control and rigour of approach must be of the highest standards in clear expectation of deep scrutiny?
(8) Your critique of the paper by McLean, Freitas and Carter (2009) hinges on arcane aspects of statistical analysis, and they stand by their comments. I have recommended publication of data with a controversial explanation precisely to get the debate going. In other areas of science the best winds out by attrition: why not here?


And there are similar questions for Briffa. Have you proved anything at all? Why do you make it so difficult to establish that? Why do you hide so much of your work and original data? Why are there so few comparisons between well known relatively reliable data and new, potentially enlightening stuff? One gets a sense that after a third reading, Kelly was muttering "bullshit, bullshit, bullshit."

h/t to both Bishop Hill and Steve McIntyre on Kelly.

A.W. Montford (Bishop Hill) says many of those who have defended the hockey stick are trying to back away from it, without admitting that the work that has generated so much grant money has been discredited.

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