From VOA News:
When it comes to greenhouse gases that contribute most to global warming, most people think of substances such as carbon dioxide, methane or even hydrofluorocarbons.
But did you know that, for a while now, scientists have considered the vapor of the most important ingredient in sustaining life on Earth – water – as one of the most abundant greenhouse gases in the atmosphere and a key driver of global warming?Well, yes. I have a textbook written in the late 1940's/early 1950's that mentions it.
A new study led by scientists from the University of Miami Rosenstiel School of Marine and Atmospheric Science confirmed that rising levels of water vapor in the troposphere – the layer of the atmosphere closest to the surface and rises to a height of between 5 to 20 km above Earth’s surface – will increasingly play an important role in climate change projections in the coming years.
The Florida researchers said their new study is also the first to demonstrate that the increasing amount of atmospheric water vapor is being caused by human activities.Interestingly, just yesterday I was wondering if we would see a story like this. I was watching a news story on CO2 emissions and the coal industry, and all of the file videos they were showing of "smoke stacks spewing" fumes were releasing steam, not smoke. (One of the photos was even of the cooling tower for a nuclear reactor).
Of course, the scientists concluded that the increased water vapor was due to increased evaporation due to increased atmospheric temperature due to human caused global warming. Got that? Increased water vapor was the result of global warming not the cause of global warming.
Well, better not breath because with each breath, you release water vapor into the atmosphere....
Update: A link to another article discussing water vapor and the global warming hypothesis. (Here).