February 14, 2009
Gerald North’s panel ruled that Michael Mann’s conclusion was right even if his study provided no basis for that conclusion, despite the response above
Of all the scientists who have come to Michael Mann’s defence, none have more impressive credentials than those of Gerald North, a former Head of the Department of Atmospheric Sciences at Texas A&M University. North, a physicist, has not only spent decades addressing the dangers of climate change, he has done so through his work in climate models and his knowledge of statistics, a suite of qualifications that make him particularly well qualified to comment on Michael Mann’s statistics-based work. Because of his background, and because Mann’s hockey-stick graph had become a source of great controversy, the National Academy of Sciences (NAS) asked North to chair a panel to investigate the statistical validity of the hockey stick graph. The NAS, like most national academies, backs the man-made global warming thesis.
The North report for the NAS, published in June, 2006, was released at a press conference and with a press release entitled: “High Confidence’ That Planet Is Warmest in 400 Years; Less Confidence in Temperature Reconstructions Prior to 1600.” Because the press release, the report, and North himself made many statements favourable to Mann, the worldwide press understandably reported that Mann had been vindicated.
“Science Panel Backs Study on Warming Climate,” read the New York Times headline. “Academy affirms hockey-stick graph” read that of Nature magazine. “Global warming is real, according to America’s top scientists, who say the earth is running its highest fever in hundreds of years,” stated NBC Nightly News anchor Brian Williams.
But the story that North and other panel members relayed less than one month later, when they were required to testify under oath, showed the NAS report to be the opposite of what most had assumed. The setting was now not a press conference but formal hearings before the Energy and Commerce Committee of the U.S. House of Representatives. Because Mann had refused to provide other researchers with the computer code necessary to verify his work, because the credibility of the science surrounding the hockey stick had become a cause célèbre, and because federal government funds had financed the hockey stick study, the Energy and Commerce committee the previous summer had decided to hold hearings into the matter.
The committee then commissioned a study by Edward Wegman, arguably America’s top statistician, and arranged for him to testify in July, 2006. Meanwhile, the NAS decided to produce a competing study into the Mann controversy, with North as its chair. The Energy and Commerce committee then decided to have Wegman and North both testify before it.
Wegman’s testimony powerfully demonstrated that Mann’s work had no validity. Then North testified in Mann’s defence, also powerfully, by showing that Mann’s conclusions were valid.
Who was right and what was going on? The following exchange between the committee chairman, Joe Barton, and North establishes who was right.
CHAIRMAN BARTON: Dr. North, do you dispute the conclusions or the methodology of Dr. Wegman’s report?
DR. NORTH: No, we don’t. We don’t disagree with their criticism. In fact, pretty much the same thing is said in our report.
Barton then asked North’s colleague on the NAS panel, Peter Bloomfield, a similar question. Bloomfield’s reply: “Our committee reviewed the methodology used by Dr. Mann and his co-workers and we felt that some of the choices they made were inappropriate. We had much the same misgivings about his work that was documented at much greater length by Dr. Wegman.”
What was going on? North’s NAS panel confirmed, without stating so clearly, that Mann’s science was shoddy, and that Mann’s conclusions, on their own, could not be trusted. But that didn’t mean that Mann’s answer was wrong – North’s panel believed that man-made global warming exists and they had lots of evidence, by other scientists, to support their belief. Therefore, the NAS panel concluded, Mann was right in his ultimate conclusion that man causes global warming, even if Mann’s study provided no basis for that conclusion.
The press can be forgiven for believing that the National Academy of Sciences panel chaired by North had vindicated the science behind the hockey stick graph, and so can singer-songwriter David Clarke.