The
Doomsday Clock is a symbol that represents the likelihood of a human-made global catastrophe, in the opinion of the members of the
Bulletin of the Atomic Scientists. Maintained since 1947, the clock is a metaphor for threats to humanity from unchecked scientific and technological advances. A hypothetical global catastrophe is represented by midnight on the clock, with the
Bulletin's opinion on how close the world is to one represented by a certain number of minutes or seconds to midnight, assessed in January of each year. The main factors influencing the clock are nuclear risk and climate change. The
Bulletin's Science and Security Board monitors new developments in the life sciences and technology that could inflict irrevocable harm to humanity.