I noticed the following statement in a recent Science article.
More limited data suggest that stratospheric water vapor probably increased between 1980 and 2000, which would have enhanced the decadal rate of surface warming during the 1990s by about 30% as compared to estimates neglecting this change. These findings show that stratospheric water vapor is an important driver of decadal glboal surface temperatures. Susan Solomon et al, "Contributions of stratospheric Water Vapor to decadal Changes in the Rate of Global Warming," Science 327, March 5, 2010, p. 1219
Note in the picture below that the world started warming at an accelerated rate in the 1980s. Gee, do you think that water vapor might be more of a cause of the scary warming they have been claiming is due solely to CO2?