The following is presented early on as axiomatic in his 1/17/08 speech. Think of how this notion is now being implimented with the recently passed cap and tax bill:
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We need a price on greenhouse gas emissions in order to motivate reaching higher into the tree, and we need research and development to bring more fruit into reach. And the final key point is that the United States has to switch from being a laggard in addressing this problem to being a leader, and we need to switch sooner rather than later if the world as a whole is to act in time to avoid catastrophic interference in the climate system."
I'm not going to do all your homework for you to answer your generic question. You will have to think, not just play contrarian.