In a warming world, atmospheric water vapour content is expected to rise due to an increase in saturation water vapour pressure with air temperature. (sciencedaily.com)
Clouds and precipitation are affected through modifications of the temperature and water vapour content of near - surface air. (ipcc.ch)
Or what the possible role of increasing / decreasing water vapour content in increasing / decreasing the radiative forcing with multi-decadal oscillations? (wattsupwiththat.com)