The fact the University of Wisconsin pays Dr. Jonathan Foley as a Professor says a great deal about academic science. The Capital Times features his Earth Day report to the State of Wisconsin Natural Resources Board. This is the report of a person well versed in computer modeling. Please, read the whole thing but focus on these specific assertions.
Climate 'out of balance,': A long-term rise of carbon dioxide, methane and nitrous oxide — mainly due to the burning of coal, oil and natural gas — warmed the Earth, he said. … Those heat-trapping gases multiplied what is a natural greenhouse effect, in which the sun heats the Earth and the Earth in turn gives off radiation in infrared waves. Those waves go into the atmosphere, which absorbs some of that heat and radiates it back down to Earth. … "The Earth is 30 degrees warmer than it would be without that natural greenhouse effect. Without it, life would never have evolved," Foley said. But humans made the greenhouse a little thicker by burning fossil fuels.
It is well established that CO2 has limited IR absorption frequencies, and if saturation of these absorption bands are demonstrable from satellite data, it is proof that additional CO2 molecules are non-contributory. In other words, once saturation is achieved, as it is in the present 300 ppm range, it is impossible for additional molecules of carbon dioxide to contribute to additional warming.
The question Dr. Foley needs to answer is this: Is there a limit to the carbon dioxide greenhouse effect, and if so, then what is that limit? I doubt any UW Professor will answer that more CO2 always means more warming, without end.