Unfortunately I think about end of the world scenarios quite frequently. I am partial to major earth changes theories, asteroid or comet collisions, man-made destruction, peak oil theories, stuff about John Titor. Just a random collection of doom. The major earth changes has to do with global warming of course. Causing what is know has the lithosphere to slip due to the bulging of water at the equator, resulting in massive slippage of tectonic plates. There are many historical proofs of this having happened in the past. I could go on all day.
I am not so concerned about survival or not. I have certain plans for certain different scenarios. It depends on the when really not so much the how. I will however have no problem reverting to a more feral form of species protecting what is mine. In this case I believe the old Marine lurking in me will come out in force. Gotta put that government subsidized training to work at some point.
Anyway, I will post some articles, book lists, etc. to expose some good theories, and will share some of my own as well. Lets see how this community goes, it could be exciting.