The Doomsday Clock is a design that warns the public about how close we are to destroying our world with dangerous technologies of our own making. It is a metaphor, a reminder of the perils we must address if we are to survive on the planet.

When the Doomsday Clock was created in 1947, the greatest danger to humanity came from nuclear weapons, in particular from the prospect that the United States and the Soviet Union were headed for a nuclear arms race. The Bulletin considered possible catastrophic disruptions from climate change in its hand-setting deliberations for the first time in 2007.