From a scientific perspective there is some indication that a nuclear war could deplete the earth's ozone layer or, less likely, could bring on a new Ice Age - but there is no suggestion that either the created order or mankind would be destroyed in the process.
I've not as yet found one hobby that would absorb me completely when I'm not working, but I have just bought a new apartment and didn't quite bargain for the amount of effort and time and money that that absorbs.