I guess maybe we're getting closer. Now, your current position is that the climate really is changing.
Like the climate, your opinion of that one keeps changing, too, but nevertheless, let's continue.
Yes, water vapor is a powerful greenhouse gas, and is in fact, part of a feedback loop, but you already know that.
And yes, water, unlike matter that stays in the same state at normal temperatures, does absorb and release heat as it changes from solid to liquid to gas.
So, you do have most of it right now.
However, there are other greenhouse gasses besides water vapor.
CO2 for example. Gasses that make up most of the atmosphere are not greenhouse gasses, as they are either monatomic, such as argon as an example (Ar), or are made up of two molecules of the same element (O2, N2) and so have no net change in dipole moment when they vibrate and hence are almost totally unaffected by infrared light.
H2O, CH4, and CO2, on the other hand, are neither monatomic nor made up of two atoms of the same element.
