Following up on his 2008 promise that “This was the moment when the rise of the oceans began to slow, and our planet began to heal,” President Obama has promised to do something about droughts, which are caused — in his opinion — by the dreaded global warming.
Obama gets a lot of his climate information from NASA’s Jim Hansen, an astrophysicist who heads the Goddard Institute for Space Studies. A federal employee, Hansen endorsed John Kerry for president in hotly contested Iowa ten days before the 2004 election. This year, he has been all over the media blaming the summer’s major drought on “global warming.”
Global-warming ideologues often make statements of “fact” that are actually testable hypotheses. Good! Let’s subject Hansen’s statement to some normal scientific scrutiny. Warning: Graphs to follow.
Hansen is saying, simply, that global warming is affecting U.S. temperatures in a way that makes us more prone to drought. Given that the equations that calculate likelihood of drought indeed include a temperature variable (warmer temperature = more evaporation), it would seem he’s home free, no?
The standard measurement of drought is known as the Palmer Drought Severity Index (PDSI); it is based upon the pioneering calculations made by Wayne Palmer, a federal hydrologist, back in 1948. When the index is below -2, that’s the threshold for drought. If it’s above +2, we are anomalously wet. The index is calculated every week for hundreds of locations around the country.
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