Why do you believe that? Some quick searches seem to indicate differently. https://www.quora.com/How-destructive-is-the-worlds-entire-nuclear-arsenal-Would-it-

Why do you believe that? Some quick searches seem to indicate differently. https://www.quora.com/How-destructive-is-the-worlds-entire-nuclear-arsenal-Would-it-make-a-difference-if-we-detonated-it-all-in-one-place-on-the-globe-e-g-one-area-of-a-desert#RwJwV https://www.quora.com/How-destructive-is-the-worlds-entire-n... for MAD to work all you need to assure is that you can damage the opponent enough that their power structure will not survive, not to destroy all of their people/land/capital.