Originally Posted by tiptap
Thank you. You are quite correct that water vapor plays a dominant position as a Greenhouse Gas. That is what your "saturation" comment is leading to by dismissing CO 2 contribution. But you are focusing on the wrong end of the atmosphere there at the surface. The Sun is Millions of degrees in its center but the sun does not throw that temperature out into space at its surface (thank whatever). The Sun acts like a black body of about 6000 degrees C. radiated from the Photosphere. That is where radiation can escape the interaction with the diminishing plasma material. The same is true with the Earth. The energy balance is controlled at the top of startosphere. That is the radiating source out. Adding CO 2 even to Venus will add positive push to the atmosphere's below temperature.
Its not my position that a trace gas plays a significant role, infact, I'm of the opposite opinion.
Perspective: CO2 comprises approx .04% of the total atmosphere (if you accept the claim)
C02 is a trace gas that's not even a 1% measurement of a fraction of it on a gobal scale falls within the margin of error and that's not counting different sampling techniques.