Global Warming Makes Drought Come on Earlier, Faster, and Harder

Droughts, one of the most intensely studied climate events, are a perfect example of an effect with both human and natural influences.  Separating the relative strengths of the influences is a challenge for scientists.  But, when we deal with drought, with its large social and economic costs, it is a challenge we must undertake.

A very recent study tries to do just this. Published in the Journal of Climate, authors Richard Seager and Martin Hoerling cleverly used climate models forced by sea surface temperatures to separate how much of the past century’s North American droughts have been caused by ocean temperatures, natural variability, and humans.  What they found was expected (all three of these influence drought), but it's the details that are exciting. Furthermore, the methodology can be applied to other climate phenomena at other locations around the globe.

The very beginning of their paper sets a great framework for the study,

In a nation that has been reeling from one weather or climate disaster to another, with record tornado outbreaks, landfalling tropical storms and superstorms, record winter snowfalls, and severe droughts, persistent droughts appear almost prosaic.  Droughts do not cause the mass loss of life and property destruction by floods and storms.  They are instead slow-moving disasters whose beginnings and ends are even often hard to identify. However, while the social and financial costs of hurricane, tornado, and flood disasters are, of course, tremendous, droughts are one of the costliest of natural disasters in the United States.

Global Warming Makes Drought Come on Earlier, Faster, and Harder