The point discussed here was to answer the question, whether the supposed atmospheric effect has a physical basis. This is not the case. In summary, there is no atmospheric greenhouse effect, in particular CO2 greenhouse effect, in theoretical physics and engineering thermodynamics. Thus it is illegitimate to deduce predictions which provide a consulting solution for economics and intergovernmental policy.
Which, given this work by two physicists, chips away another brick in the wall of "scientific concensus." And which the authors also address (p. 94 middle)
A theoretical physicist must complain about the lack of transparency here, and he also has to complain about the style of the scientific discussion, where advocators of the greenhouse thesis claim that the discussion is closed, and others are discrediting justified arguments as a discussion of "questions of yesterday and the day before yesterday." In exact sciences, in particular in theoretical physics, the discussion is never closed and is to be continued ad infinitum, even if there are proofs of theorems available.
Are these gentlemen right about the lack of a CO2 greenhouse effect? Good question, well worth a legitimate scientific discussion, one not subject to blackballing from "peer-reviewed" journals or secret data and even more secret calculations and models.
By the way, this was published in January 2009, well before the ClimateGate emails emerged.