from what ive seen this isnt true actually. Hollywood likes to make it seem that way, but H-bombs, which pretty much all modern nukes are, are a lot less radioactive than the ones dropped on Hiroshima and Nagasaki, and you see how those places have recovered pretty quickly. Nuclear winter is just a theory, and even if it did happen it wouldn't entirely wipe us out. Some places would survive it, and people would rebuild. Now yes most people would die in a nuclear winter, and even if the winter didnt come just the bombs would kill a ton. But humanity wouldnt end.