The Doomsday Clock is a symbol that represents the likelihood of a man-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.The clock's original setting in 1947 was seven minutes to midnight. It has been set backward and forward 24 times since, the farthest from midnight being 17 minutes in 1991, and the nearest being 100 seconds, from 2020 to the present.

The clock was moved to two and a half minutes in 2017, then forward to two minutes to midnight in January 2018, and left unchanged in 2019. In January 2020, it was moved forward to 100 seconds before midnight. The clock's setting was left unchanged in both 2021 and 2022. Since 2010, the clock has been moved forward over four minutes, and has changed by five minutes and twenty seconds since 1947.

Since 1947, the clock has been moved backward eight times and forward 16 times.