How will the world end?

Probably the most important thing to discuss when it comes to a Post-Apocalyptic (P-A) world is what form the apocalypse took. Science fiction (and fantasy) have presented us with many possibilities, including war, plague, asteroid/impact, ecological collapse, alien invasion and supernatural upheaval.

Most of these have really similar elements.

1. A whole lot of people die, rapture or get kidnapped by aliens. In any case, they're gone.
2. Loss of people results in loss of government, or at least a vastly weakened government. Survivors are suddenly on their own. This can be anywhere from one lone person who mysteriously survives a plague, to entire cities building walls to keep out the crazies in the wastelands.
   
3. Frequently, though not always, the environment becomes hostile. This might due to radiation, flooding, ash clouds blotting out the sun, or zombies all over the place.
   

The kinds of P-A worlds that interest me most are the ones where government, and indeed civilization itself has collapsed, leaving smaller groups of survivors to independently fend for themselves. These survivors must fight the environment and competing groups to survive. For me, the Mad Max movies, the computer RPG Fallout and the novel/movie The Postman are good examples of this.

In future posts, I'll try to focus on some of these different kinds of apocalypses and try to bring out some of the differences.