Yes, the amount of vapor increases, which also contributes to global warming. But at the same time, the relative humidity might go down if the capacity of the a

Yes, the amount of vapor increases, which also contributes to global warming. But at the same time, the relative humidity might go down if the capacity of the air to hold water increases faster than the actual vapor amount. The consequence is: while there is more water in the air, there is less accessible for the plants.