I read On the Beach back in high school, over 30 years ago, along with Alas, Babylon. Both of these were post-nuclear war stories, but had completely different endings, as I recall. Humans have survived (as a species) any number of disasters; civilizations have risen and fallen throughout all of recorded history.

What I found interesting is the possible correlation of Dec. 21, 2012 with a Solar conjunction with the center of the Milky Way galaxy. Many of the cultures who had this type of prophecy were adept astronomers, measuring star motions with eye-popping precision. One way this may be read is the human fear of the unknown, "this has never happened before; must be bad". Eclipses, comets, meteor showers were often considered harbingers of disaster, and often appear to correlate. However, there's a rule (from logic?) correlation does not mean causation.

Even though I'm a skeptic, I find the idea of people (who live in linear time for the most part) which have the ability to "peek" very fascinating.