Assume you buy that human emissions are driving enough of climate change that if we removed that driver things would stay "cool enough". China has already markedly surpassed the U.S. as the largest total CO2 emitter, and they're not even close to the U.S.'s per capita emissions. Even if they can manage to continue to industrialize while only emitting per capita as much as the nuclear-heavy French, you're still looking at an increase of 15-20%, and I think that's optimistic. AFAIK, the Chinese are building coal fired power plants as fast as they can.
And that's just China. India and Africa would like to enjoy a Western quality of life as well.
I am extremely skeptical that CO2 emissions can be substantially curtailed, short of a world economic collapse that would make 2007-2009 look like a walk in the park.
But I am more than willing to be convinced. I think it would help the alarmed AGW folks immensely if they would unify around a politically impractical "if we ruled the world" plan. One sufficiently detailed that it could be analyzed for its climatic, economic and social effects, as well as publicized, criticized and modified until it becomes practical. A starting point might be, "Tax fossil fuel extraction at the source at levels sufficient to reduce emissions the necessary N%". But then you have to figure out what to do about the facts that this sort of plan would likely never be accepted by Russia or China, and that it's a massively regressive tax on the world's poor. There are solutions to these issues. Figure them out, add them to the plan, lather, rinse, repeat. If something like this already exists, I haven't seen it.