(Nov. 6. 2009) Politicians the world over claim that 4,000 scientists believe in global warming. Depends on who’s counting.

In a speech yesterday, Australia’s Prime Minister Kevin Rudd explained why he is so certain that the science is settled on climate change. It stems from the number 4,000 — a number that the United Nation’s Intergovernmental Panel on Climate Change used to publicize its last major report.

“This is the conclusion of 4,000 scientists appointed by governments from virtually every country in the world,” asserted Mr. Rudd, in making his case that the planet is in peril.

Unfortunately for Mr. Rudd, he has made a blunder in citing this number. As he can confirm by contacting the secretariat of the IPCC, the thousands of scientists upon whom he rests his case never endorsed the IPCC’s report. Rather, the secretariat will advise him — as the Secretariat advised me when I inquired in 2007 — that the great majority of those scientists were merely reviewers. Worse for Mr. Rudd, those scientists had reviewed only a fraction of the report. Worst of all, far from endorsing the IPCC’s conclusions, many of the reviewers turned thumbs down on the IPCC sections that they read and only a handful actually endorsed the IPCC’s claims that man-made global warming represents a threat to the planet.

The upshot? Australia has turned its economy inside out largely on the basis of imagined endorsements.

How could Rudd have made this mistake? He was tricked by the PR machine at the IPCC. Look at the accompanying illustration from a public relations flyer that the IPCC distributed and you can see how easy it is for an unsuspecting person to be tricked. The work of “2,500+ scientific expert reviewers, 800+ contributing authors, 450+ lead authors from 130+ countries” had culminated in one report, the flyer states. The not unreasonable implication that almost everyone drew was that those 3,750-plus experts and authors stood behind the IPCC’s views of impending doom.

The rest is history. A tricked press reported those figures, often rounding the 3,750-plus people to 4,000. And then the public and the politicians such as Rudd were tricked, too.

How many of those 3,750-plus people from 130-plus countries can the IPCC claim as true backers of its conclusions? An Australian analyst named John McLean scrutinized the lists that the IPCC used to arrive at its figures and found them to be riddled with duplications, such as the 383 authors who also acted as reviewers for the same sections in which their work appeared, and the authors and reviewers who were listed twice or thrice. Remove the duplications and the total number of authors plus reviewers drops from 3,750 to 2,890.

The reviewers, as might be expected, made suggestions. In about 25% of the cases, the editors rejected the suggestions – another indication that the verdict on the IPCC’s report was far from unanimous.

Most importantly, the great majority of the reviewers commented on chapters that dealt with historical or technical issues — matters that didn’t support the IPCC’s conclusions on man-made climate change. The exception was Chapter 9 — Understanding and Attributing Climate Change. An endorsement here would clearly be a bona fide endorsement of the IPCC’s conclusion.

Chapter 9 had 53 authors and it received comments from 55 individual reviewers. Of the 55 individuals, four commented favourably on the entire chapter and three on a portion of the chapter. (To give you the flavour of these endorsements, reviewer David Sexton stated that “section # 9.6 I think reads pretty well for the bits I understand” and reviewer Fons Baede’s endorsement was “Chapter 9 SOD has improved considerably and is very readable and informative.”)

The 53 authors and seven favourable reviewers represent a total of 60 people, leading McLean to conclude: “There is only evidence that about 60 people explicitly supported the claim” made by the IPCC that global warming represents a threat to the planet. Sixty scientists among the 130-plus countries that the IPCC cites amounts to one scientist for every two countries.

Prime Minister Rudd needs to do his sums, just as John McLean and others have. There is no scientific consensus on climate change. There is no basis to undertake the radical economic changes that he and other western leaders propose. There is, on the other hand, a good reason for the public in Australia to balk at his radical plans — they are no longer taken in by the IPCC’s public relations department.

Lawrence Solomon is executive director of Energy Probe and Urban Renaissance Institute and author of The Deniers: The world-renowned scientists who stood up against global warming hysteria, political persecution, and fraud.

Read the sources for this column.