the world isn't gonna just magically explode one day; anybody who believes that is an idiot.
the only way there would be a sudden "end of the world" is if every country decided to detonate their nuclear weapons & kill us all.
of course, we could all die out gradually from pollution/global warming/diseases etc (i think that's the most likely chance of humans dying out besides war), but there's no way we're all just going to cease to exist on some arbitrary day.
oh, and of course... in about a billion years the sun will be too hot for water to exist anymore so that would pretty much end life on earth... and then in about 5 billion years the sun is gonna enter a red giant phase and the earth could get swallowed up by it; that would be the only real "end of the world".
but yea, that's so gradual, it's ridiculous to think it could happen in one day.