This Week's Ignoratio Elenchi Award

ignoratio elenchi n.
A logical fallacy of presenting an argument that may in itself be valid, but has nothing to do with the proposition it purports to prove. Also known as “irrelevant conclusion”. [Lat. ignorance of refutation.]

On Monday, an article appeared in the Washington Times that offers so many outrageous examples of the logical fallacy of irrelevant conclusion (formally, ignoratio elenchi) that I’m beginning a new series of posts – the Ignoratio Elenchi Awards – for the most flagrantly misleading arguments against curbing greenhouse gas emissions.

Our inaugural Ignoratio Elenchi Award goes to John Linder for his Op-Ed piece in the Washington Times, “Global-warming theory and the eugenics precedent“, which is packed with examples of ignoratio elenchi. There was the argument about water vapor (see article on water vapor). And the argument that scientists previously warned of an imminent ice age (see article on global cooling).

But the award-winning ignoratio elenchi is that eugenics thing – don’t believe scientists because scientists once embraced eugenics. Come on. First of all, eugenics was not about science, it was about applying science (genetics) to social engineering. And, it was a bad idea, agreed. But what does that have to do with climate science?

Not all Linder’s arguments were logical fallacies. Some were plain old bad science – for example, his argument for why carbon dioxide (CO2) added to the atmosphere since the Industrial Revolution is not from the burning of fossil fuels.

Linder correctly points out that CO2 amounts have varied in the past. He then notes that 400,000 years ago, CO2’s concentration was 280 ppm. So far so good. But then, like his apparent mentor Michael Crichton, Linder strays from science fact into science fiction. Linder claims that 280 ppm is “about what it was 20 years ago,” and asks, “Who was burning the fossil fuels 400,000 years ago?”

Wrong. The pre-industrial CO2 concentration was 280 ppm, the same as it was 400,000 years ago. Twenty years ago the CO2 concentration was 350 ppm. Today the concentration is 380 ppm. CO2 concentrations today are higher than they’ve been in at least the last 650,000 years.

How do we know that most of the increase in CO2 since the Industrial Revolution is due to the burning of fossil fuels, and not natural fluctuations?

CO2 is a molecule that contains carbon atoms, and most of the carbon atoms on the earth come in two forms. About 99% are what we call carbon-12, and about 1% are carbon-13. In measuring atmospheric CO2, scientists found an interesting trend: CO2 was increasing over time, but the ratio of carbon-13 to carbon-12 was decreasing. Measurements of tree rings showed that this trend began in the late 1800’s.

The explanation? The percentage of carbon-13 in fossil fuels is less than the percentage of carbon-13 in the atmosphere. So when fossil fuels are burned, the ratio of carbon-13 to carbon-12 in the atmosphere decreases.

This trend is proof-positive (like a fingerprint or DNA match) that the additional carbon in the atmosphere since the late 1800’s came from the burning of fossil fuels.

Hmm… Maybe we need a second award for blatant misunderstandings of science.

Seen any outrageous logical fallacies or outrageous misinterpretations of science? Please post your nominations for future recognition.

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