The Doomsday Clock is historically significant because it transformed the abstract, technical threat of nuclear war into a universally understood symbol of urgency. And in the last eight decades it has become a cornerstone of the cultural framework that treats nuclear weapons and climate change as existential, rather than just political, problems. Before the clock, nuclear strategy was a secret language spoken only by generals and physicists. To be sure, this decision was scientifically sound — climate change is indeed an existential threat — but it also muddled the message. Whenever the clock moved before, everyone knew it was about nuclear bombs.