It was only a matter of time...

Here it is, the inevitable "Man it's hot, it must be global warming!" article.  If there is anything my obsession with econometrics has taught me, it's that a single observation is indicative of...well...nothing.  In isolation, the current heat wave is no more evidence of global warming than a single negative drug test is evidence that Barry Bonds never did steroids.  But if you look at long term trends...