Experts from 2008!-----Wayback Machine - Water Vapor Confirmed as Major Player in Climate Change 11.17.08

Wayback Machine

"Water vapor is known to be Earth’s most abundant greenhouse gas, but the extent of its contribution to global warming has been debated. 

Using recent NASA satellite data, researchers have estimated more precisely than ever the heat-trapping effect of water in the air, validating the role of the gas as a critical component of climate change.
Andrew Dessler and colleagues from Texas A&M University in College Station confirmed that the heat-amplifying effect of water vapor is potent enough to double the climate warming caused by increased levels of carbon dioxide in the atmosphere...