08 December 2009

Krugman vs. Hansen

UPDATE: Jonathan Adler has more at Volokh.

Paul Krugman takes Jim Hansen to task over his arguments against cap-and-trade expressed in the NYT yesterday:
James Hansen is a great climate scientist. He was the first to warn about the climate crisis; I take what he says about coal, in particular, very seriously.

Unfortunately, while I defer to him on all matters climate, today’s op-ed article suggests that he really hasn’t made any effort to understand the economics of emissions control. And that’s not a small matter, because he’s now engaged in a misguided crusade against cap and trade, which is — let’s face it — the only form of action against greenhouse gas emissions we have any chance of taking before catastrophe becomes inevitable. . .

Things like this often happen when economists deal with physical scientists; the hard-science guys tend to assume that we’re witch doctors with nothing to tell them, so they can’t be bothered to listen at all to what the economists have to say, and the result is that they end up reinventing old errors in the belief that they’re deep insights. Most of the time not much harm is done. But this time is different.

For here’s the way it is: we have a real chance of getting a serious cap and trade program in place within a year or two. We have no chance of getting a carbon tax for the foreseeable future. It’s just destructive to denounce the program we can actually get — a program that won’t be perfect, won’t be enough, but can be made increasingly effective over time — in favor of something that can’t possibly happen in time to avoid disaster.
Hansen is right about cap-and-trade, but for the wrong reasons. It won't fail because of economics, but because of politics. Krugman is right that Hansen's economics are muddled, but wrong that cap-and-trade is "the only form of action against greenhouse gas emissions we have any chance of taking before catastrophe becomes inevitable." Debates like this help to explain why we need more not less voices in the climate debate.