They can sign anything they want at Copenhagen, unless it gets ratified by the Sentate, it won’t mean a thing. There are still some things that Obama can’t do by executive decree (at least for now.)
Hundreds of pompous, overstuffed PhD’s are going to look really foolish in another ten years when we go another decade with rising CO2 levels but without any increase in global temperatures. At a scientific level, it’s starting to look like some PhD’s screwed up their AGW theory because they’ve greatly underestimated the ability of the oceans to radiate heat away from the earth. So while CO2 may initially capture additional energy from the sun, that energy doesn’t stay on the earth and doesn’t build up over time. AGW theory will end up being a classic example for the ages of people foolishly jumping on the bandwagon for fun, profit, and a sense of purpose in their lives.