Horse patoot.  The volume of water vapor in the atmosphere dwarfs CO2.  Who told you that?

You're probably looking at the many charts showing all of the greenhouse gases EXCEPT water vapor.  I see them all the time.  Very deceptive.

Case in point.  The Saraha Desert is the hottest place on the planet.  It has about the same amount of CO2 as everywhere else but very little heat trapping water vapor.  If a cup of water is left outdoors overnight in the Saraha, it will often freeze.

The problem the AGW agenda has with that fact is they can't get any money declaring war on water.