William Briggs reads Coby Beck‘s guide to arguing in favor of Anthropogenic Global Warming, and encounters a new form of scientific argument.

A few weeks ago I speculated what would happen if human-caused significant global warming (AGW) turned out to be false. There might be a number of people who will refuse to give up on the idea, even though it is false, because their desire that AGW be true would be overwhelming.

I guessed that these people would slip into pseudoscience, and so would need to generate excuses why we have not yet seen the effects of AGW. One possibility was human-created dust (aerosols) blocking incoming solar radiation. Another was “bad data”: AGW is true, the earth really is warmer, but the data somehow are corrupted. And so on.

I failed to anticipate the most preposterous excuse of all. I came across it while browsing the excellent site Climate Debate Daily, which today linked to Coby Beck’s article “How to Talk to a Global Warming Sceptic“. Beck gives a list of arguments typically offered by “skeptics” and then attempts to refute them. Some of these refutations are good, and worth reading.

His attempt at rebutting the skeptical criticism “The Modelers Won’t Tell Us How Confident the Models Are” furnishes us with our pseudoscientific excuse. The skeptical objection is

There is no indication of how much confidence we should have in the models. How are we supposed to know if it is a serious prediction or just a wild guess?

and Beck’s retort is

There is indeed a lot of uncertainty in what the future will be, but this is not all because of an imperfect understanding of how the climate works. A large part of it is simply not knowing how the human race will react to this danger and/or how the world economy will develope. Since these factors control what emissions of CO2 will accumulate in the atmosphere, which in turn influences the temperature, there is really no way for a climate model to predict what the future will be.

This is as lovely a non sequitur as you’re ever likely to find. I can’t help but wonder if he blushed when he wrote it; I know I did when I read it. This excuse is absolutely bullet proof. I am in awe of it. There is no possible observation that can negate it. Whatever happens is a win for its believer. If the temperature goes up, the believer can say, “Our theories predicted this.” If the temperature goes down, the believer can say, “There was no way to know the future.”

What the believer in this statement is asking us to do, if it is not already apparent, is this: he wants you to believe that his prognostications are true because AGW is true, but he also wants you to believe that he should not be held accountable for his predictions should they fail because AGW is true. Thus, AGW is just true.