A slight change of ocean temperature (after a delay caused by the high
specific heat of water, the annual mixing of thermocline waters with deeper waters in storms) ensures that rising CO2 reduces infrared absorbing H2O vapour
while slightly increasing cloud cover (thus Earth's albedo), as evidenced by the fact that the NOAA data from 1948 - 2008 shows a fall in global
humidity (not the positive feedback rise presumed by NASA's models!)