In an earlier post, I suggested that the "accredited experts" who signed an anti-climate science petition could be broken into three categories: Scientific Iconoclasts; Lazy Pseudo Experts; and Self-Interested Scoundrels.

I perhaps missed a category - as above: Scientific Dinosaurs whose numbers have dropped below the level that is critical for their survival. Their kind is extinct, even if they don't know it.

Witness, first, the small number. When these critics launched this kind of a petition in the United States seven years ago, they got 2,100 signatures (many of which were phoney, but that's another problem). This time, the group - representing many of the same names - could generate just 60 signatures, notwithstanding that they had to go to the ends of the earth and round up every "sceptic" still on the list.

In Canada, there is a risible clutch of deniers - fewer than 20 - and the extinct-but-don't-know-it category seems well-represented. They are, often, legitimate scientists who committed themselves a decade or more ago to a position that turns out to be incorrect. Some argued that climate change was being caused by sunspots or by other naturally occurring variations - theories that, in their day, had some compelling supporting data.

Alas, the day is past. The worldwide consensus - shared by every major science council in the developed world, by the Intergovernmental Panel on Climate Change, by Shell Oil, British Petroleum and General Electric, even by old Conservative war horses like former Canadian Prime Minister Brian Mulroney - is that the other theories just don't wash. The climate is changing, with a speed not witnessed in millions of years, and human are responsible.

But dinosaurs like Tim Ball continue to advocate disinterest. They have mostly abandoned any attempt to sincerely address the science, choosing instead to cling to uncertainty. (Look at Ball's piece and you will see many legitimate scientists admitting -- fully and fairly -- that climate science is highly complex and inexact; no no mention that all those scientists agree that the ultimate conclusion is certain, indeed.)

Our dinosaurs are also reduced to quoting one another for support (as Ball does in attacking Tim Flannery's new best-seller, The Weather Makers).

At the end of the day, it is appropriate to feel a certain amount of compassion for these people, holding so desperately to discredited theories and simpler answers. It would be uncharitable to put them into the same category as villains like Steve Milloy, who will shill for the tobacco industry or the fossil fuel industry without suffering the slightest crisis of conscience.

But they are still wrong; they refuse to admit that they're wrong; and in propping up the Self-Interested Scoundrels, they are dragging the whole human race closer to the point of being extinct without knowing it. There has to be a certain circle in Dante's hell for people - really intelligent people - who would make that kind of mistake.