While I agree completely with the theme of this commentary — I also completely disagree with the above statement. It's just plain gibberish.
There are so many good reasons to reject the AGW hypothesis — this isn't one of them. It just creates a straw-man for the warm-mongers to knock down.
Its also true.
Co2 is a gas.
Water for instance; it exists here as ice, which can absorb heat and change state to water. It can absorb heat again and change state to a gas.
CO2 cannot do that because it is already a gas, and it is why CO2 is irrelevant in global warming. It cannot hold any more heat energy.
In the original article in #6, none of that is mentioned.