Brian Schmidt wants to bet on global warming

Earlier this week I linked to an interesting piece by a global warming skeptic. In the comments, Brian Schmidt cordially invited me to back my skepticism with a bet.

I declined.

But I tried to explain to Brian exactly what about global warming I'm skeptical about. For the possible interest of other readers, here's a summary.

1. I'm mildly skeptical that global temperature can be defined to the complete satisfaction of betting parties. Air temperature or ground temperature? If ground, with or without correction for the urban heat island effect? Year-round or only in some seasons? All latitudes or only some? Both day and night or only one? Over what time span to control for short-run noise? (How do you know that a given span
is the "right" length?) Temperature as measured by whom?

2. I'm a bit more skeptical of how advocates of the global warming hypothesis address lay audiences. When I ask a physicist if special relativity is correct or when I ask a biologist if evolution is correct, I expect to get an explanation--even if oversimplified--of the theory and some discussion of the evidence. In contrast, I hear a lot of global warming advocates--Laurie David, most recently--yelling "Settled science! Settled science! Consensus! Nobody but the paid, right-wing stooges of the oil companies believes otherwise!" That contrast raises my suspicions. Especially when I read what folks like Freeman Dyson have to say (see and also this Wikipedia entry on Professor Dyson). Is Freeman Dyson a paid stooge? Might the difference have to do with how incredibly complicated and poorly understood the global climate models are? (For links to two other crtiical comments on the "consensus" see and

3. I'm even more skeptical about the amount of the warming, if any, that is anthropogenic. In Brian's betting post, I count 10 different bets, but only one involves anthropogenic warming: hurricanes increase in intensity "partly" due to anthropogenic warming. "Partly"?? Does 10% count? Does 1% count? Who determines the percentage?

To me, this is quite revealing. If the planet is getting warmer, but people have little to do with it, 99% of the public discussion of global warming is off point and useless. And Brian proves nothing with most of his bets.

4. Finally, I'm most skeptical--in part because of #3 and in part because of other, independent reasons (for example, the opportunity cost point that Bjorn Lonborg makes) that public policies centered on controlling carbon or some of its compounds are anything close to economically sensible. As I've noted, Aaron Wildavsky's framework seems much, much better (see point #4 of this post:

I'll conclude by noting that my focus is on #4, the public policy we allegedly need to combat global warming. That's an important reason why I don't want to bet Brian; he seems mostly interested in betting on the fact of warming. But this raises a reasonable question: why, then, if I'm interested in policy do I link to articles and comments that question the fact of global warming?

As I wrote Brian, this is simply a strategy of argument. There's a story about a lawyer whose client is accused of murder. In his opening statement the lawyer tells the jury "My client is innocent because he wasn't there; if he was there, he didn't kill anybody; and if he did actually kill someone, he had a good reason!" I want to debate the policy implications of global warming, and as noted, I feel strongly about Kyoto-type policy. But like a good lawyer, I want to use all the possible arguments. So: 1) maybe we don't have to worry, there isn't any warming; 2) maybe there's warming, but it's not anthropogenic, so we don't need a preventive policy; and finally, 3) maybe it is primarily anthropogenic, but the proposed preventive and corrective policies are still ill-advised. Given the stakes involved--billions and quite possibly trillions of dollars--I don't see why I should surrender points 1 and 2 without very careful consideration. 

But my focus--indeed, my almost exclusive concern--is policy. 

The rest is simply a consequence of the fact that in 21st century America, we're all lawyers now.