Having read much in the popular press, heard most of the talking heads on TV and radio, watched Al Gore's film and seen the opinions posted in this forum, I can't resist giving my $.02 worth.
Almost everyone is missing the point. We shold be doing everything feasible the "experts" recommend to combat global warming. However, we shouldn't see the environmental benefit as our primary objective. It is much more importantly a matter of national security and economic stability.
We absolutely should be running a "Manhattan Project" scale alternative energy effort to drop the bottom out of our oil consumption. This accomplishes several important things. First and foremost, it reduces our dependence upon resources we don't control and for which we face increasing competition. Second, it diminishes extranational political influence. Third, it increases the need for domestic manufacturing and distribution. Fouth, it moves our economy away from a dying model and toward the future. Fifth, it leaves plenty of incintive for our cheif competitors (China and India) to remain stuck on the old model for decades to come. This will again give us a strategic advantage that has been eroding over the last several years. Sixth, it will dry up some of the funding sources for Persian Gulf state sponsored terrorism.
That's why we should do all the green stuff. Not because of some questionable science. The one true thing Bill Clinton ever said was "It's the economy; stupid!"