Well, stockpiles are significantly down relative to the Cold War peak, due to strategic arms reduction treaties. Detonation of Cold War peak stockpiles would ha

Well, stockpiles are significantly down relative to the Cold War peak, due to strategic arms reduction treaties. Detonation of Cold War peak stockpiles would have been "really bad" for the human race. Likely not an existential threat for humanity as a species, though very possibly one for the current state of human civilization.