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!)