I heard a presentation by an interested party to the global warming issue. He presented a series of graphs describing the amount of radiation emanating from the planet, unsure if it was long wave or short wave but it was related to the question. Also I can not remember the name of the researcher.
The upshot of the research was that the planet is releasing more radiation back into space than would be expected if the levels of CO2 were in fact trapping heat in the atmosphere.
The presnter was a gentleman by the name of Monkton