Gemini what where you smoking when you watched that Nova show? The world's Co2 level is already a third higher than ever in recorded history, half of the world's coral reef's have already died and the glaciers are in full retreat. I don't think you payed any attention to the scientists on the show who weren't on the big oil payroll.
http://www.pbs.org/wgbh/warming/
I watched the same show and It all pretty cut and dry: Fossil fuel = Co2 = Greenhouse.
Just wait until China, India, Brazil and Indonesia start burning like we do, then your gonna see Waterwolrd without Kevin Costner.