Just because the H2O molecules are microscopic and airborne does not make them a gas. If you want to really understand what is going on track back to what I was saying about the characteristics of a designer warming gas. I said it would be heavy for one thing. Its not water vapour which fits this bill. Its microscopic liquid water.
We have been suckered in a lot of ways. Blinded since we don’t think water is liquid if it is airborne and it is in a form smaller than a droplet. We cast it all under the rubrick of “water vapour.”
But the whole key to this story is microscopic liquid water. Because if this story were only about water vapour and rain, then water vapour would be the planetary refrigerant par excellence. The water vapour, absorbing so much from above and below would just travel on up, it would rain, the latent heat of condensation would be let out in all directions, but since there is more air below then above….. because of this, more than half of that heat would be as good as lost in space right there. Water Vapour is the oceans sweating. Water Vapour would be the cooling gas. But because airborne H2O, is always going backwards and forwards between water as vapour, and also as microscopic liquid water, then THIS microscopic-liquid-water, is what serves as the proxy for our designer warming gas.
We saw that CO2 was no good as a warming gas, except perhaps at night, or to some extent in association with overturning. We saw that Ozone was a fine warming gas if you lived on the highest mountain peaks. We said that a really good warming gas would be powerfully heavy. And it would only absorb the low end. So then it would act like the fat short-stop, catching all the balls, being driven outside of the diamond, then coming back to home base, still catching balls and banging into the other fielders on the way in.
But while we might find heavier and heavier gases as candidates to do this job, there is no gas that is going to be as heavy as the microcopic airborne liquid water we are talking about here. This is the whole key to the entire story of this tawdry and wrong notion to do with the make-believe “greenhouse effect.”