An observed consequence of higher water vapor concentrations is the increased frequency of intense precipitation events, mainly over land areas. (earthobservatory.nasa.gov)
There is no convincing data to support the idea that CO2 level regulates atmospheric water vapor concentration. (theinconvenientskeptic.com)
The lapse rate effect is discussed in every textbook on the subject, the small additional effect due to changing water vapor concentration not. (judithcurry.com)