Well, let's see. Let's do some ratios based on the physical chemistry reference texts. Round numbers.

Water vapor outguns CO2 by ~100-fold in concentration.

Water vapor outguns CO2 in heat capacity ~100-fold.

The implication is that the water vapor contribution to global warming, by simple mass action, is essentially ~10,000 fold that of CO2.

So while I can't predict the temperature of the next few years or century, I can prove that CO2 can't be more than 4th digit correction to whatever does happen, et ceteris paribus.