Douthat sketched out the conservative case against cap-and-trade yesterday. Leonhardt takes issue with one of Ross's parallels:

[Douthat's case is that] just as ingenuity came to the rescue in the past, allowing people to use resources more efficiently than they ever had before, it could do so again providing us with ways to emit far less carbon for every dollar of gross domestic product. And I like many others, I imagine would be thrilled if that were what the future held. But I think there are two big reasons to doubt that we’re on another Ehrlich-Simon path when it comes to global warming.

The first is basic economics. When the problem is resource scarcity, companies and individuals have a powerful incentive to become more efficient. It keeps their costs down. Mr. Simon understood this, and it’s the fundamental reason he won the bet.

But global warming is different. The fact that carbon emissions are warming the planet doesn’t make it more expensive to produce those emissions. So companies do not have an ever-increasing incentive to emit less the way they would if the problem were, say, a lack of oil. Global warming doesn’t solve itself the way that resource scarcity does.

The second reason is the data: it's far more robust on global warming than on predictions of future resource scarcity. My view is that a small but steadily increasing carbon tax is a modest way to help accelerate energy innovation and guard against the possibility of quite drastic shifts in temperature caused by climate feedback loops. I also find a pure human cost-benefit analysis lacking when it comes to something like the health of the planet. But then that's my Catholic side coming through, I guess. We have a moral duty for proper stewardship, in my view, not relentless exploitation until disaster strikes. And I fail to see why such prudence is now regarded as un-conservative.

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