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Mann-made science does not support the hypothesis that global warming is man-made
By Lawrence Solomon
A good scientist, like a good journalist, checks his facts, if for no other reason than to spare himself embarrassment and to immunize himself from charges that he’s casual with the truth, lazy or just plain dishonest. Michael Mann has not checked his facts.
Mann’s article has two main thrusts. First, he attempts to discredit me and others who have criticized his work. Then, he attempts to defend his reputation by claims that distinguished authorities, especially the National Academy of Sciences, have endorsed his hockey stick graph. His graph is an icon in the global warming debate: It convinced the press and the public that 1998 was the hottest year of the hottest decade of the hottest century of the last 1,000 years, creating the belief that Earth was changing dangerously for the worse.Let me deal in chronological order with Mann’s attempts to discredit those he perceives to be his critics.
Mann calls the National Post a tabloid, presumably because tabloids have a reputation for sensationalism. The Post is not a tabloid; it is a broadsheet, and a fine one at that, considered by many to be Canada’s best newspaper.
Mann claims I am funded by the fossil-fuel industry. I am not and neither is Energy Probe Research Foundation, the federally registered charitable organization that I helped found in 1980 and that I have represented continually since. There is a good reason the energy industry does not fund Energy Probe: Over the decades, Energy Probe has been Canada’s chief critic of the energy industry, more responsible than any other organization for stopping ill-advised energy pipelines, coal plants, tar sands projects, nuclear plants and large hydro dams.
Energy Probe is a leading promoter of conservation and alternate energy, and it prides itself on being non-partisan — parties of all stripes in Canada, from the leftist New Democratic Party to the centrist Liberal party to the right-leaning Conservative party, have invited Energy Probe to their gatherings, and adopted its positions.
Mann also attacks Joe Barton, in 2006 the head of the Energy and Commerce Committee in the U.S. House of Representatives. The “Barton attacks” he refers to concern hearings this committee held to discover whether Mann’s hockey stick graph was the product of sound science, as Mann claimed, or a statistical sham, as his critics claimed. The person commissioned to ascertain the truth was Edward Wegman, one of America’s finest scientists and, ironically, the past chairman of the Committee on Applied and Theoretical Statistics of the National Academy of Sciences, the very body that Mann cites as supporting his work.
Wegman assembled a panel of blue-chip statisticians, all of whom worked pro bono for the Barton committee, and for good measure the panel subjected its work to top level reviewers, such as the Board of the American Statistical Association. The Wegman panel’s findings? Mann’s critics were entirely in the right, Mann lacked the statistical knowledge to do the work he had taken on, and Mann’s work had not been subjected to a credible peer-review process.
When Mann cites the support of the National Academy of Sciences, he is not referring to Wegman’s findings but those of another NAS panel, this one headed by another top statistician, Gerald North. The so-called “support” that the NAS panel provided to Mann would mortify many in Mann’s position.
The NAS did find some of Mann’s work “plausible” — that’s the closest that it comes to actually supporting Mann’s findings — but then it immediately states there are so many scientific uncertainties attached to Mann’s work that it doesn’t have great confidence in it. The committee then proceeds to further downgrade its view of Mann’s work: “Even less confidence can be placed in the original conclusions by Mann et al. (1999) that ‘the 1990s are likely the warmest decade, and 1998 the warmest year, in at least a millennium.’ ”
In short, Mann’s main conclusions are not to be believed.
Why not? Because “Mann et al. used a type of principal component analysis that tends to bias the shape of the reconstructions” and because he downplayed the “uncertainties of the published reconstructions.” And, the NAS added, because of what Mann did not do — he did not let others examine his data for accuracy and he did not reveal his analytic methods. For this, the NAS rightly chastised Mann: “Our view is that all research benefits from full and open access to published data-sets and that a clear explanation of analytical methods is mandatory. Peers should have access to the information needed to reproduce published results, so that increased confidence in the outcome of the study can be generated inside and outside the scientific community.”
Conclusion about the hockey stick graph: Mann-made science does not support the hypothesis that global warming is man-made.
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