Schrag doesn't think it's all that complicated

and neither do I, honestly. He is quoted in a news article in Science.

Geochemist Daniel Schrag of Harvard University argues that mandatory carbon caps should have been applied years ago to force energy technology innovations. He doesn't think that it's necessary to have, as Bush proposed, a year and a half of discussion to define emissions goals. "We know what we need to do now," he says.

PS - Like anyone in or around the paleoclimate science community, I have the utmost respect for Dan Schrag.