Jonathan Chait has written a column, titled Half-Baked, in the current issue of The New Republic that attacks the global warming positions that I have presented in National Review.

Global warming is a complex topic that depends upon inherently speculative predictions about the world’s economy and environment more than a century into the future, so there is plenty of room for principled disagreement. As a general rule, however, people like Mr. Chait who speak about it in tones of certainty mostly reveal that they are uniformed on the subject. While I recognize the constraints on length that prevented him from producing a doctoral dissertation, he never actually engages with the central arguments that I’ve made, at any level of abstraction.

A simplified version of my core argument can be presented in one paragraph:

Carbon dioxide is greenhouse gas, and if you put more of it in the atmosphere, then all else equal the Earth will get warmer. The key unknown, because of the complexities of climate feedbacks, is how much warmer. The UN IPCC forecasts that Earth will get something less than 3C hotter within about a century, and further estimates that 4C of warming would cause the world to lose 1% – 5% of GDP; therefore the expected costs of global warming are on the order of 3% of GDP sometime well into the 22nd century. This is a huge amount of money, but not exactly consistent with Miami becoming an underwater theme park. Given that global consumption is projected to grow from about $6,600 per person per year today to about $40,000 per person per year over the next century, it’s pretty hard to justify massive sacrifice of wealth today for the purpose of preventing our descendants a hundred years from now being only 5.7 times, instead of 6 times, as rich as we are. The real risk is that science has radically understated the greenhouse effect. A carbon tax designed for the expected case can safely be avoided for decades, while a carbon tax high enough to ameliorate a low-odds disaster scenario would be insanely expensive. Relatively low-cost investments in specific technologies that would be useful if such a disaster scenario arose, on the other hand, are a smart insurance policy.

Here is how Mr. Chait presents my views:

Republicans are no longer denying the scientific basis for global warming. That’s good news for those of us who have grown accustomed to the continued existence of things like polar sea ice, various forms of life, and Miami. The bad news is that Republicans, having seen the light, have fallen back on the possibly even more annoying stance of simply refusing to do anything about the problem.

The new conservative stance was presaged last summer in a National Review cover story, “Game Plan: What Conservatives Should Do About Global Warming.” The article, by Jim Manzi, began with a frank acknowledgement that global warming could no longer be denied. After this promising start, the argument swiftly degenerated. Manzi proposed “development of tactical technologies, such as carbon sequestration and cleaner-burning [oil-fueled] engines.” Of course, everybody is for those things. The problem is that dirty energy sources like oil and coal are far cheaper—and will remain cheaper for a long time—unless the government somehow increases the cost of carbon emissions. This, however, is where Manzi begs to differ. “Conservatives,” he writes, “should propose policies that are appropriately optimistic, science-based, and low-cost.”

How, exactly, conservatives can persuade people to give up cheap energy sources without imposing a cost on them Manzi does not say. (Perhaps this is where being “optimistic” comes in.) ….

Rather than address the uncertainty that is at the heart of the problem, Mr. Chait falls back on scare stories and cat calls.

Mr. Chait then goes on to describe the political strategy that I outlined in NR:

Instead, he proceeds to a gleeful discussion of how conservatives could win votes by opposing carbon taxes—most likely by luring “old-line industrial-union members” ticked off by the soulful entreaties of Al Gore and other members of the “Hollywood and political smart set.” The essay concludes on the triumphal note, “Global warming can be the first wedge issue of the 21st century.”

I believe that clever conservative politicians could make this a winning political issue, because upon careful inspection it becomes apparent that the proposed programs to radically reduce carbon emissions through taxes or regulation are very likely to cost much more than the benefits they provide. Mr. Chait finds it impolite to mention this in mixed company because it would disadvantage his preferred political candidates. Sorry about that.

The second part of Mr. Chait’s article is devoted to criticizing a specific oil industry tax advantage about which I have no informed opinion, and about which I do not believe I have ever expressed an opinion.

(cross-posted at The Corner)