"20 way the world could end" see how egocentical we are as a species? we might be gone but in most of these scenarios the WORLD will still be here

some of these are plausable but highly unlikely

"alien invasion" why? because we have such a pristine planet? nah!
to qoute Douglas Adams "far out in the uncharted backwaters of the unfashionable end of the Western Spiral arm of the galaxy lies a small unregarded yellow sun. orbiting this at a distance of roughly ninety-eight million miles is an utterly insignificant little blue planet"
http://discovermagazine.com/2000/oct/featworld/article_view?b_start:int=0&-C=