The earth doesn't know it's 2012.
2012 is a Christian date and forgive me for saying but I don't think the earth has a religion. It's not going to reach 2012 and think it must self-destruct. On other calenders (correct me if I'm wrong) such as the Islam and Jewish calendars 2012 was a while ago.... like 3,000 years ago. Don't you ever think the Mayan calender ended in 2012 because they simply got bored of counting?
#offtopic.