Oh please....every single generation has thought that mankind/the earth/the universe would be destroyed during their lifetime. Sure there are more threats on a global level, but those won't be in the form of direct human actions such as a nuke war, the only thing nukes have managed to do is create stability between the mightiest nations, offcourse today only America is the only great nation (and happily exploiting it), but no country capable of ending the world with nukes will do this. Besides, we get more and more international treaties, EU, UN, WTO etc. this adds even more to stabillity.No, direct human action only causes destruction on a relatively small scale. What we really need to be worrying about is the slow deah of mankind through it's indirect actions (global warming, extinction of animals etc.), this won't be a single day, or a week, or a year, no this will take hundreds of years, if not thousands. Such an extensive time period does not give birth to a world of chaos, but to a world no other than the one we are currently living in, every period of time, humanity will simply be in a stable state of growing concern or carelessness, because 'science will stop it'.