How does the author use foreshadowing in Cat's Cradle?

John's reference to August 6, 1945 as the day the world ended is ironic. Assuming that nuclear holocaust is inevitable, in one sense, the statement is correct. The day the first bomb was dropped was the beginning of the end. In another sense, the statement is ridiculous, since John is writing in 1968. From yet a third perspective, the world will in fact end, but as a result of the secret weapon Ice-nine, rather than nuclear war. In this way, the book's title foreshadows the end of the world.