Six Questions for Levitt and Dubner (More Superfreakonomics Blogging)
Global Warming

Paul Krugman on Superfreakonomics on Climate

Paul Krugman writes:

Superfreakonomics on climate, part 1: OK, I’m working my way through the climate chapter.... The chapter opens with the “global cooling” story — the claim that 30 years ago there was a scientific consensus that the planet was cooling, comparable to the current consensus that it’s warming. Um, no.... To the extent that there was a consensus, it was that there wasn’t much evidence for anything.... What you have today is a massive research program involving thousands of scientists and many peer-reviewed publications, with all major international bodies agreeing that man-made global warming is real. You can, if you insist, dismiss it all as a gigantic hoax or whatever--but it’s nothing like the isolated 70s speculations about cooling.

And then we come to a bit of economics.... Yikes. I read [Marty] Weitzman’s paper... it’s making exactly the opposite of the point they’re implying it makes. Weitzman’s argument is that uncertainty about the extent of global warming makes the case for drastic action stronger, not weaker. And here’s what he says about the timing of action:

The conventional economic advice of spending modestly on abatement now but gradually ramping up expenditures over time is an extreme lower bound on what is reasonable rather than a best estimate of what is reasonable.

Again, we’re not even getting into substance — just the basic issue of representing correctly what other people said.