The magnetic field of Earth has been getting weaker, allowing a larger influx of various rays in the EM spectrum. These rays, especially the gamma rays, affect the 'intelligence' of all living creatures.
In addition, our 'global ruling elite', who have paid well for the advice of the top men in their fields, are aware that the HOUSE OF CARDS they built (the way the world manages and distributes natural resources) is going to come crashing down. This will lead to mass panic, so the are investing mega billions in secure underground cities stocked with supplies.
As a consequence of leaving biological and nuclear stores 'unprotected', the abandoned masses will quickly eliminate themselves.
After it is safe, the New World Order will crawl out of their holes and start over.
This is the Dawning of the Age of Aquarius, Age of Aquarius.... (and will not be quite what these folks had in mind)
BTW, it officially starts on Dec 21, 2012.