Global warming is moistening the atmosphere

http://www.theguardian.com/environment/climate-consensus-97-per-cent/2014/aug/13/global-warming-moistening-the-atmosphere

Posted by John Abraham
Wednesday 13 August 2014

We have long suspected that greenhouse gases which cause the Earth to warm would lead to a wetter atmosphere. The latest research published by Eul-Seok Chung, Brian Soden, and colleagues provides new insight into what was thought to be an old problem. In doing so, they experimentally verified what climate models have been predicting. The models got it right… again.

To be clear, this paper does not prove that water vapor is a greenhouse gas. We have known that for years. Nevertheless, the paper make a very nice contribution. The authors show that the long-term increase in water vapor in the upper troposphere cannot have resulted from natural causes

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I asked Dr. Andrew Dessler about this study, and he told me,

Because of water vapor’s importance as a greenhouse gas, the water vapor feedback occupies a central role in the climate system. Over the years, our understanding of this process has increased steadily, and this paper is a very useful contribution. It nicely demonstrates that the observations of upper tropospheric moistening are unlikely to have arisen without the increase in carbon dioxide from human activities. At this point, I think it would be fair to say, “stick a fork in it, the water vapor feedback’s done.”