Crooked!

Michael Mann has finally buckled to pressure from Congress and has released to the public a version of the FORTRAN program he used to calculate his "hockey stick" reconstruction of the earth's climate. It looks like the program released is a modified version of the original rather than the original itself. No doubt Mann will say that the original is "lost". I modify my FORTRAN programs almost every time I run them so that is not entirely implausible. But even what has been released is damning. It shows that Mann reported only those statistics which suited his conclusions and suppressed other statistics that threw his conclusions into serious question. As Steve McIntyre notes:

However, the newly-archived source code demonstrates clearly that MBH did calculate the cross-validation R2 statistic (pages 28-29 in my printout). Accordingly, I can now assert that the information was withheld in the original SI.

At this point, we also know that the values of the cross-validation R2 were very insignificant (~0.0) in the controversial 15th century reconstruction. One can reasonably surmise that this information would have been very detrimental to widespread acceptance of the MBH98 reconstruction had it been disclosed. The IPCC assertion that the MBH98 reconstruction “had significant skill in independent cross-validation tests” is obviously not true for the withheld cross-validation R2 statistic. I previously discussed this inaccurate disclosure by IPCC as illustrating the potential conflict of interest between an author in his capacity as an IPCC review author and in his capacity as the author of the underlying study.

While I anticipated that the code would demonstrate the actual calculation of the cross-validation R2 statistic, there was a bit of a surprise in the form of another discrepancy between statistics calculated in the program and statistics reported in the original SI.

The program shows that a verification period RE statistic was calculated for the Nino index; however, the original SI only reported a verification period R2 statistic – reversing the reporting pattern for the NH temperature index. In this case, I presume that the verification RE statistic for the Nino calculation will be adverse. However, I have not attempted to replicate the MBH98 Nino calculations and this is merely a surmise at present.

I strongly believe that the authors had a responsibility to report adverse statistics, such as the cross-validation R2, and were not entitled to withhold this information. This also applies to Wahl and Ammann, who similarly do not report a cross-validation R2 statistic. In their case, their code as published does not even include the calculation of cross-validation R2 statistics in their calculations , but I would be astonished if they had not calculated these values at some point and later edited the step out of their code.....

It’s late in the day to be arguing these matters after positions have been taken and locked in. I have no doubt, as I’ve mentioned recently, that, if the IPCC had reported that the MBH98 reconstruction had a cross-validation R2 of ~0.0 (rather than claiming that it had “significant skill in independent cross-validation tests”), the MBH98 hockey stick graph would not have been featured in IPCC. If it had been reported in the original publication, it’s possible that the original article would not have been published in the first place. It will be interesting to see what the various learned societies and individuals will make of this.

So the whole global warming scare is shown to be largely based on a scientific fraud.

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