Facts and Theories, Updated
The fact that its radiates off energy does not make CO2 a greenhouse gas – at least not at the concentrations we observe. But look no farther than Mars. Its atmosphere is almost totally CO2 and Mars is stone cold. Where is the greenhouse effect when the concentration exceeds Earth more than 10000 times? Venus has a hot CO2 atmosphere and is the archetype of a greenhouse effect. But is it really. Or would a pure nitrogen atmosphere thats as thick as the Venusian atmosphere is, not be as hot as it is with CO2?