Alarming!

Now that I'm a farmer, I take an interest in something called "hardiness zones" which tell me how cold it can get where I am planting and what will and will not grow there.  I never knew what zone I was in until recently.  It seems I am in zone 6.  But here's the thing: a couple of years ago I would have been in zone 5.  In 2006, they changed the zones, because some places had warmed up so much.  I found a nifty, but worrying animation of the shift in zones from 1990 to 2006 here.  Check it out.  It kinda gives me the willies.