Reply to Scott Sumner on Global Warming
By David Henderson
Scott Sumner writes:
I recall that when liberals favored lots of “command and control” regulation to address global warming, and conservatives favored a carbon tax. That was the “market solution” comparable to the market-based approach to reducing sulfur emissions from coal-fired power plants. Some conservatives now latch on to “contrarians” in the scientific community. OK, but how come when the shoe was on the other foot conservatives would talk about “scientific consensus.” For instance, conservatives used to criticize a lot of the excessive regulation of chemicals in the environment, by pointing to scientific studies that showed many of the pollutants that environmentalists were obsessing about did not have a statistically significant impact on health. When I read the Wall Street Journal in the 1970s it seemed like it was the clear thinking conservatives relying on science vs. the muddy-headed romantic environmentalists.
As Scott knows, I am not a conservative, but I couldn’t help but think that he was criticizing libertarians also when those libertarians oppose a carbon tax. On the assumption that Scott is including libertarians, here’s my response:
It’s hard to talk about an amorphous group when Scott doesn’t name or otherwise identify any of them, other than to call them “conservatives.” So I’ll speak for myself.
I still criticize much regulation of chemicals in the environment and it’s true that I point to “scientific studies that showed many of the pollutants that environmentalists were obsessing about did not have a statistically significant impact on health.” I don’t recall, though, that I’ve talked about “scientific consensus.” I have remained open to other scientific studies. What I have not done is put the same weight on the views of an environmentalist with no scientific standing as I have on the views of a scientist who is informed about the issue.
I do the same with global warming. There was a statement years ago, signed by about 31,000 people, claiming that global warming is not a big deal. Various people quoted it, claiming that it was signed by thousands of scientists. It’s possible that it was. But I didn’t have the time to do due diligence on the names of the signers and so I have never quoted it.
Also, even if I were to talk about “scientific consensus” as a shorthand when I want to talk about a scientific issue in which I am not expert (which is the vast majority of them), I would not dismiss criticisms or objections on the grounds that they challenge the consensus. I would definitely not refer to those who disagree as “deniers.”
Later in his post, Scott has anticipated one of the defenses, writing:
A note to commenters. Before you mention some study that has the support of 5% of climate scientists, ask yourself how you’d feel if some massive liberal big government intervention was being proposed on the basis [of] studies that 5% of scientists supported, and 95% thought were nuts. Wouldn’t you ridicule the heterodox view?
My answer is “No, I wouldn’t ridicule the heterodox view. I would consider the reasoning and try, as best I could, to examine the evidence.”
But where does Scott get the 5%? He doesn’t say. I have written here and here, as has David Friedman here and here, about the suspect nature of the claim that 97% of scientists believe that global warming is caused mainly by humans.
Notice, though, a little irony. Why did Scott start blogging and what is he best known for? For arguing that the Federal Reserve should target nominal GDP and that its failure to do so was the main factor responsible for the 2007 to 2009 Great Recession. In a survey of business economists, what percent of them agreed with his view that monetary policy had been too tight? As Scott points out, it was 6.6 percent, which is uncomfortably close to his 5% number.
Does this cause Scott to doubt his own views? No, it doesn’t. Now there is a difference here that Scott could reasonably argue is important. The difference is that Scott is an expert on monetary policy in a way that I am not on global warming.
But if Scott held the same standard for other people, he would have to argue that non-experts on monetary policy should pay his views little or no heed. How about it, Scott. Would you?
Note: Bob Murphy has covered some of the same ground here.