I am not a climate expert, but I think you're grossly downplaying the complexity of the climate change problem. There are so many factors in play. Its not just a matter of CO2 emissions. There is methane from animal livestock, contrails from aircraft, cloud cover, methane hyderates in the ocean, sunspot activity; Even the average reflectance of the earth's surface(http://en.wikipedia.org/wiki/Albedo). Every year the scientist's models and theories seems to be changing. All we seem to know for sure is that global average temperatures are indeed rising.

I have the sneaky (unscientific) suspicion that whatever drastic measures we would inevitably have to take to curb CO2 emissions is going to open its own can of worms. The footprint of human activity is simply that large.