H20 joins the precipitation cycle but due to increasing temperatures there is more H2O in the atmosphere than before on average.

So yes. We do have more atmosphere than before.

Both by mass and by number of molecules.

The energy we've put into the system will eventually go back to the previous equilibrium after hundreds of years. So it's temporary on the earth's timescale at the moment.

Unless we put too much energy in then it releases more energy, methane released, ice caps melted, less heat reflected, and the change becomes more of an earth timescale one than a human timescale one.