Categorized | Health

A Test of the Tropical 200-300 mb Warming Rate in Climate Models

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By Ross McKitrick | Climate Etc.

I sat down to write a description of my new paper with John Christy, but when I looked up a reference via Google Scholar something odd cropped up that requires a brief digression.

Google Scholar insists on providing a list of “recommended” articles whenever I sign on to it. Most turn out to be unpublished or non-peer reviewed discussion papers. But at least they are typically current, so I was surprised to see the top rank given to “Consistency of Modelled and Observed Temperature Trends in the Tropical Troposphere,” a decade-old paper by Santer et al. Google was, however, referring to its reappearance as a chapter in a 2018 book called Climate Modelling: Philosophical and Conceptual Issues edited by Elizabeth Lloyd and Eric Winsberg, two US-based philosophers. Lloyd specifically describes herself as “a philosopher of climate science and evolutionary biology, as well as a scientist studying women’s sexuality” so readers should not expect specialized expertise in climate model evaluation, nor do the book’s editors exhibit any. Yet Google’s algorithm flagged it for me as the best thing out there and positioned two of its chapters as top leads in its “recommended” list.

Much of the first part of the book is an extended attack on a 2007 paper by David Douglass, John Christy, Benjamin Pearson and Fred Singer on the model/observational mismatch in the tropical troposphere. The editors add a diatribe against John Christy in particular for supposedly being impervious to empirical evidence, using flawed statistical methods and refusing to accept the validity of climate model representations of the warming of the tropical troposphere.

By way of contrast, and as an exemplar of research probity, they reproduce the decade-old Santer et al. paper and rely entirely on it for their case. If they are aware of any subsequent literature (which I doubt) they don’t mention it. They fail to mention:

  • Santer bitterly fought releasing his data
  • Despite having data up to 2007 he truncated his sample at 1999
  • If he had used the same methodology on the full data set he’d have reached the opposite conclusion, supporting Douglass et al. rather than supposedly refuting them
  • Steve McIntyre and I submitted a comment to the journal showing this. It was rejected, in part because the referee considered Santer’s statistical method invalid and didn’t want it perpetuated through further discussion
  • We re-cast the article as a more detailed discussion of trend comparison methodology and published it in 2010 in Atmospheric Science Letters. We confirmed, among other things, that based on modern econometric testing methods the gap between models and observations in the tropical troposphere is statistically significant.

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