"the IPCC argues that feedbacks from increased water evaporation will lead to enhanced warming. This is not observed in those regions most effected by water vapour. In fact the opposite seems to be the case implying negative feedback."His analysis compares the most ARID stations [low humidity/water vapor] with the most WET stations [high humidity/water vapor] and finds that
"There is a clear trend in the data that ARID stations cool faster and warm faster than WET stations."
"Water Feedback = - 1.8 +- 0.2 W/m2K-1
Remarkably this is the same value as that derived from a simple argument regarding the Faint Sun paradox see here."