[Edi]

As I said, for the same amount of water vapor vs CO2, CO2 is more efficient as a greenhouse gas. In the big picture water vapor is greater in overall effect. If you remove all other factors and increase CO2 amount, total heat goes up (assuming normal radiative transfer to space on the night side). This does not address all of the other possible, probable and confirmed mechanisms involved. It doesn't need to, because if those other mechanisms are responsible, they must be identified sufficiently that they can be countered.

Your article says there is no effect on temperature from CO2, therefore CO2 is irrelevant to global warming. I just pointed out a whole host of reasons why that reasoning is flawed at best. We know the properties of CO2, but we don't necessarily know all of the other mechanisms involved as well as we would like and they may very well have an effect beside CO2 that causes alterations. So CO2 is more fuel for the fire, just not the only fuel. But when you're fighting a blaze, as it were, you don't add more fuel to it.

The biggest problem overall is overpopulation, because it causes all sorts of other things that exacerbate other effects.