The "how world will end" discussion is really a severe case of public paranoia (mayan calendar ends = end of the world); yet, the idea is scary, and can happen at any second. Some asshole decides to risk the lives of billions to retain fear over the world with nuclear missiles, let it be an american, arab, or just some stupid kid.
But when it ends, all the conspiracies, and only one truthful to its end, it's horrible to see how it happens. The screams of those running in vain. The way they see their surroundings crumble apart. The way you see your loved ones look at you in despair, and there's no way you can stop it.
I hope it is confirmed as preventable, because the world will consume itself in fear, and, well, we'll be responsible for it by then.