IPCC must come clean on real numbers of scientist supporters

IPCC must come clean on real numbers of scientist supporters

The UN Climate Change Numbers Hoax

By Tom Harris: John McLean Friday, December 14, 2007

It’s an assertion repeated by politicians and climate campaigners the world over – ‘2,500 scientists of the United Nation’s Intergovernmental Panel on Climate Change (IPCC) agree that humans are causing a climate crisis’.

But it’s not true. And, for the first time ever, the public can now see the extent to which they have been misled. As lies go, it’s a whopper. Here’s the real situation.

Like the three IPCC ‘assessment reports’ before it, the Fourth Assessment Report (AR4) released during 2007 (upon which the UN climate conference in Bali was based) includes the reports of the IPCC’s three working groups. Working Group I (WG I) is assigned to report on the extent and possible causes of past climate change as well as future ‘projections’. Its report is titled “The Physical Science Basis”. The reports from working groups II and II are titled “Impacts, Adaptation and Vulnerability” and “Mitigation of Climate Change” respectively, and since these are based on the results of WG I, it is crucially important that the WG I report stands up to close scrutiny.

There is, of course serious debate among scientists about the actual technical content of the roughly 1,000-page WG I report, especially its politically motivated Summary for Policymakers which is often the only part read by politicians and non-scientists. The technical content can be difficult for non-scientists to follow and so most people simply assume that if that large numbers of scientists agree, they must be right.

Consensus never proves the truth of a scientific claim, but is somehow widely believed to do so for the IPCC reports, so we need to ask how many scientists really did agree with the most important IPCC conclusion, namely that humans are causing significant climate change--in other words the key parts of WG I?

The numbers of scientist reviewers involved in WG I is actually less than a quarter of the whole, a little over 600 in total. The other 1,900 reviewers assessed the other working group reports. They had nothing to say about the causes of climate change or its future trajectory. Still, 600 “scientific expert reviewers” sounds pretty impressive. After all, they submitted their comments to the IPCC editors who assure us that “all substantive government and expert review comments received appropriate consideration.” And since these experts reviewers are all listed in Annex III of the report, they must have endorsed it, right?

Wrong.