The above points are good ones (I don't refer to the w/u immediately above; that one's just amusing). However, I have to question the conclusion.
"Reducing emissions rather than cleaning up afterwards just seems more sensible. Correct me if I'm wrong."
Be glad to try.
The emissions reductions you are talking about would cripple the economy. If you're talking about something like the Kyoto Protocol, the economy would be absolutely annihilated. So what? Well, technological progress is greatly nurtured in a buzzing economy. In a stagnant, stalled economy, there is not as much money to go around for research and development. In a depressed economy, the situation is even worse.
The point is that technological solutions to global warming (which we still don't understand in the least) look infeasible and far-out now. They look very pie-in-the-sky. If emession cuts are passed, and scientific research slows, those solutions will be infeasible for much longer. Instead of quickly creating new solutions to our problems, we are merely putting off the time that we'll be able to act.
In other words, emissions cuts is the irresponsible, short-sighted one. It will cripple our abilities in the future to deal with whatever problems there are. Pushing technology ahead will work better, not just in making the techniques we know of now cheaper, but even more importantly in creating new techniques that we can hardly fathom now. It's not just the benefits we can forsee; it's the benefits we won't know about until we discover them.
Better tech creates more efficient power plants. Better tech creates more effictient combustion engines. Emission cuts will happen naturally, pushed forward by the economy and technology. Then, when we fully understand whatever problem we face (we have very little real understanding of how, or if, global warming or cooling works), we'll have the tools with which to deal with it.
Technology is the solution to problems created by technology. Period.