0) Since the troposphere has actually warmed only 0.5C in the last forty years, and the world is rapidly reducing human CO2 emissions (which turn out to be a smaller fraction of the total than previously thought), there is little to worry about, and we should direct our efforts at resolving more important issues.
I'm not an expert but my impression of the issue is like we are headed to (1) no matter what and they are trying to say that if we keep digging up and burning coal and venting or burning natural gas then we are in danger of reaching (2). But the headline says (3) and the deniers say (0).
0) Since the troposphere has actually warmed only 0.5C in the last forty years, and the world is rapidly reducing human CO2 emissions (which turn out to be a smaller fraction of the total than previously thought), there is little to worry about, and we should direct our efforts at resolving more important issues.