1960s: The Population Bomb.Read the annotated list at American Digest.
1970s: No oil by 2000.
1970s: The new Ice Age.
1990s-present: Global Warming.
2000s: Bird Flu.
2008: The credit crunch.
There have been so many over the years.
Nuclear armageddon also springs to mind.
No matter the age or level of civilisation there will always be these points of panic and uncertainty, and there will always be those who advocate drastic action (tossing virgins into volcanoes for examples - couldn't do it in Aus, no volcanoes and I'm unsure about finding a virgin).
There will always be those who will profit from (mostly irrational, unfounded) fear.
People who believe this crap are Doomers, or Apocaholics. Read more about the affliction and its causes at itulip.
(That should keep you occupied for a little while.)
Thanks to Pogs for the lead.