Good job this new NK leader didnt inherit China or then we really would have something to worry about! Fortunately even the Chinese and Russians are washing their hands of NK. You can say what you want about globalisation but one good thing about it is that nuclear war would be bad for business and nobody wants that. Glad I don't live in Asia though.
Having said that even a small nuclear incident causes far longer term effects across the world that most people realise. The entire earth is now covered in tiny particles of nuclear materials from the various incidents we've had over the years, even as far away as both of the poles. I did a hair mineral analysis thing once which shows what you're consuming and tested positive for Uranium, even though I've never been near any nuclear sites. Same results for everyone who is tested apparantly
