The Clock, which evokes both the imagery of apocalypse (midnight) and the contemporary idiom of nuclear explosion (countdown to zero), is run by the Bulletin of the Atomic Scientists since 1947 and has become a universally recognized indicator of the world's vulnerability to catastrophe from nuclear weapons, climate change, and emerging technologies in the life sciences.
This year, the Board of Directors moved the Clock at 3 minutes before midnight (from 5 set in 2012) and placed the emphasis on climate change.
"The world leaders have failed to act with the speed or on the scale required to protect citizens from potential catastrophe," the board said.
"Unchecked climate change, global nuclear weapons modernizations, and outsized nuclear weapons arsenals pose extraordinary and undeniable threats to the continued existence of humanity.
These failures of political leadership endanger every person on Earth. Despite some modestly positive developments in the climate change arena, current efforts are entirely insufficient to prevent a catastrophic warming of Earth. Meanwhile, the United States and Russia have embarked on massive programs to modernize their nuclear triads - thereby undermining existing nuclear weapons treaties.
The clock ticks now at just three minutes to midnight because international leaders are failing to perform their most important duty - ensuring and preserving the health and vitality of human civilization."
The clock’s minute hand stood at two minutes before midnight in 1953 after both the United States and the Soviet Union conducted their first tests of the hydrogen bomb, and at 17 minutes before midnight in 1991, after the end of the Cold War. The last time it was just three minutes to midnight was in 1983, when US-Soviet relations were at their iciest.
In 2015, with the Clock hand moved forward to three minutes to midnight, the board feels compelled to add, with a sense of great urgency: "The probability of global catastrophe is very high, and the actions needed to reduce the risks of disaster must be taken very soon."