If something like this happened today and lasted 18 months, it would be the worst calamity that has ever befallen the planet when mankind was on it. The local agriculture of 535 A.D. was the least sophisticated arrangement for the survival of individuals and therefore the best way to weather such a disaster.
Today with half the planet depending on just-in-time inventories and agribusiness it would kill off 5 billion people or thereabouts with ease.
Why did the Norway seed bank have to be completed and sealed by 2011?
Why has the U.S. government been tunnelling everywhere for so long?
I think a lot of people who believe something is going to happen in 2012 have been selling the sheeple lullabyes for a long time because they believe it is something that only they will need to survive.