Originally posted on Tallbloke's Talkshop:
Roy Clark left this as a comment on Bishop Hill:
Most people, including many scientists, have been fooled by the pseudoscience that is hidden in the climate models. Every single result produced by the use of radiative forcing is invalid. The results from all of the models that use the empirical radiative forcing constants given by the IPCC are fraudulent.
The full explanation is little involved, but here goes:
In order to understand the issues it is necessary to go back to the beginning and look at the original 1967 paper by Manabe and Wetherald [J. Atmos. Sci. 24 241-249 (1967), ‘Thermal equilibrium of the atmosphere with a given distribution of relative humidity’. This can be found at http://www.gfdl.noaa.gov/bibliography/related_files/sm6701.pdf
The assumptions made in the derivations are clearly stated on the second page.
The Earth’s climate is stable, which means that there is an approximate energy balance between the incoming solar radiation and the outgoing LWIR flux somewhere ‘at the top of the atmosphere’. This is simply a statement of the First Law of Thermodynamics. The energy is conserved – more or less. However, this does not justify the assumption that an ‘average climate equilibrium state’ exists in which the solar flux is exactly balanced by the LWIR flux.