That's the question put to some international scientist types. Their responses are worth a perusal and a some a chuckle:
[T]he Mayans predicted Dec. 23, 2012, as the end of the age, we will be fully into Aquarius by around 2010, I read that the Vedas claim 2011 as the change of ages, and of course most Christians tell me that it won't be long. Coincidence? But maybe our ever accelerating rate of overconsumption of earth's biomass, our omnipresent pollution, all the wars, etc., will all be solved in the next 8 years, and we'll be OK.