Dealing with true believers I find that decisions are made with a herd mentality, so I try to keep it simple as possible. 1365W/m2 is the solar constant.
Look at the IPCC Radiative forcing analysis from 1750 to 2005. It shows CO2 being 1.6W/m2 or 0.6 degree F(1.6/520Fx1365W/m2). Nature (the sun) produces 520F above absolute zero or Nature 99.9% of the temperature on earth and man 0.1%. In terms of the 60F greenhouse effect Nature 99% man 1%. Get a grip on reality!