The “Demonstrably Flawed” Congressional Testimony of John Christy

Posted on March 12, 2011


John Christy is one of the scientists I was talking about in More Fires Than Mongols: Illusions of Controversy in Climate Change, one of the few actual climate scientists who deny the basic tenets of climate change science–his rarity meaning, of course, that he and his opinions get endlessly recycled.  For every public appearance or quote from individual climatologists who actually agree with the scientific consensus–which is 97.5% of them–professional climate deniers like John Christy will get quoted a hundred or a thousand times by the media.

And then claim he’s being ignored.

John Christy–not one to worry about being recycled too often and all out of proportion to his scientific importance–recently testified before Congress on behalf of the Republican Party, itself the world leader in political climate science denial.

But eminent climate scientist Benjamin D. Santer thinks there may be major scientific flaws to Christy’s congressional testimony, as the following open letter makes clear.

I have had a quick look at John Christy’s recent Congressional testimony.  Many aspects of it are deeply troubling. From my own personal perspective, one of the most troubling aspects is that Christy cites a paper by David Douglass, John Christy, Benjamin Pearson, and S. Fred Singer.  The Douglass et al. paper appeared in the online edition of the International Journal of Climatology (a publication of the Royal Meteorological Society) in December 2007.

Shortly after its publication, it became apparent that the authors of the Douglass et al. paper had applied a flawed statistical significance test.  Application of this flawed test led them to reach incorrect scientific conclusions.

Together with a number of colleagues (including Gavin), I prepared a response to the Douglass et al. paper.  Our response was published by the International Journal of Climatology in October 2008. (DOI: 10.1002/joc.1756) I am also appending a “fact sheet” providing some of the scientific context for both the Douglass et al. and Santer et al. International Journal of Climatology papers.)

To my knowledge, the Douglass et al. International Journal of Climatology paper has never been retracted.  Nor have the authors acknowledged the existence of any statistical errors in their work.  The fact that John Christy has now cited a demonstrably-flawed scientific paper in his Congressional testimony – without any mention of errors in the Douglass et al. paper – is deeply disturbing.

It is my opinion – and the opinion of many of my scientific colleagues – that the Douglass et al.  International Journal of Climatology paper represents an egregious misuse of statistics.  It is of great concern that this statistically-flawed paper has been used (and is still being used) as crucial “evidence of absence” of human effects on climate.

Benjamin D. Santer
Program for Climate Model Diagnosis and Intercomparison
Lawrence Livermore National Laboratory