I would add that there has never been a documented observation that gaseous CO2 and other greenhouses gases DID NOT act as greenhouses gases.

While we can debate, at this point in time at least, how strong of a role different concentrations of greenhouse gases have in effecting Earth's surface temperature, to conclude that they DON'T play a role is the equivalent of saying that ALL of the previous observations concluding that greenhouse gases ARE greenhouse gasses are incorrect...even though there has NEVER been objective data found to defend that conclusion.