Global Warming Is Moistening the Atmosphere

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 – it is clearly human caused.  This conclusion is stated in the abstract,

Our analysis demonstrates that the upper-tropospheric moistening observed over the period 1979–2005 cannot be explained by natural causes and results principally from an anthropogenic warming of the climate.  By attributing the observed increase directly to human activities, this study verifies the presence of the largest known feedback mechanism for amplifying anthropogenic climate change.

As stated earlier, climate models have predicted this moistening – before observations were available.  In fact, the models predicted that the upper troposphere would moisten more than the lower atmospheric layers.  As the authors state,

Given the importance of upper-tropospheric water vapor, a direct verification of its feedback is critical to establishing the credibility of model projections of anthropogenic climate change.

Global Warming Is Moistening the [Upper] Atmosphere