I should point out that nuclear war is actually the least likely end on that site, human nature may give us the desier to nuke someone that's pissing us off but human nature also will drive us to not piss someone off that might nuke us...overpopulation of cats in Australia is more likely to end us then nukes because it's something we never think about so it will likely get too far before we really pay enough attention to it to stop it, and by that time to bird population in australia will be drastically lower causing huge repercusions in the balance of nature