Is it now? How then did the Snowball Earth situation come to be? If the atmosphere is very cold, it will not hold much water vapor. So, if there is a serious deficit of GHGs in the atmosphere, there will be little water vapor in the atmosphere. Water vapor in the atmosphere is a feedback effect of the GHGs in the atmosphere.Of course it is. And the determining factor is the temperature of the atmosphere and water. And the GHGs determine the temperature of the atmosphere and water. Without the GHGs in the atmosphere we would have ice on the oceans clear down to the equator. That has actually happened in deep geological time.No, Frankie boi, as explained many times, the residence time for H2O in the atmosphere is about ten days. So H2O is a feedback from the GHGs with much longer residence times, CO2 and and CH4.
While your statement is factually correct, you also have to remember that while the residence time is 10 days, the H2O in the atmosphere is being perpetually replenished.
Mark
"Snowball Earth" Confirmed: Ice Covered Equator
So why bring it up? If H2O is perpetually replenished, the residence time means nothing.
Mark
I don't know what happened in the past. No one does. So tell me, how did the Earth climb out of the "snowball" situation?
Mark