CUTTING CARBON EMISSIONS -- FUN AND EASY. I don't think Ezra should be so quick to concede the infeasibility of big reductions in carbon emissions. The notion that this would require earth-shattering economic sacrifices is the product of an unfortunate conspiracy between regulation-averse right-wingers who don't want us to do anything about the problem, and the modernity-averse faction of environmentalism that wants us to overreact. See this post by John Quiggin for the long form of the argument. He concludes that the requisite changes would cost "between 1.5 per cent and 3 per cent of GDP. That�s about one year�s worth of economic growth [over a period of decades]. Remember that this estimate is not for the modest first steps required under Kyoto, but for a reduction in emissions on the scale required to stabilise climate." Along those lines, it's worth recalling that our current economic policies are not perfectly optimized to maximize growth anyway (just consider the loss associated with our unwillingness to adopt the metric system, to say nothing of serious problems), and we could change other things to make up the (relatively small) cost.
For the United States, this not-so-painful transition could be rendered much less painful by comprehensively reforming zoning and other regulatory restrictions on high-density land use. Settlement patterns have a giant impact on energy use, most obviously in the realm of transportation but also in terms of heating. There's plentiful evidence from America's hot, hot coastal housing markets that sprawl-loving Americans want to adopt less-sprawling living habits even absent carbon emissions considerations and that we're being dissuaded from shifting as rapidly in this direction as we'd like by the high cost of living near a vibrant urban core which, in turn, is mostly driven by zoning rules.
Somewhere in Ross's initial post, he concedes that the British have been able to combine robust economic growth with significant carbon reductions, but doubts this is possible for poor countries. It should actually be easier. Since China doesn't already have people living in highly energy-intensive settlement patterns, the price associated with adopting policies that discourage them from adopting such patterns will be very low. There won't be any dislocation at all. It just means that average Chinese citizen in 2050 will live more like typical residents of New York City or Brussels than like typical residents of the Dallas-Ft. Worth metropolis. Getting Texans to embrace that switch will be, at a minimum, a bit tricky psychologically. But since either choice is clearly preferable to being a dirt-poor peasant farmer or sweatshop laborer, I think the Chinese wouldn't really mind this vision of their future.