7 Moments in the History of the Doomsday Clock

In 2026, the Doomsday Clock was set at 85 seconds to midnight—the closest it has ever been to signaling global catastrophe. The decision, made by the Bulletin of the Atomic Scientists’ Science and Security Board (SASB) reflected a convergence of escalating threats: renewed nuclear tensions, the rapid rise of artificial intelligence, mounting biological risks and the accelerating climate crisis.

Since 1947, the Doomsday Clock has served as a powerful symbol—and a public reckoning—of how close humanity stands to self-destruction. Here are 7 moments that have shaped the Clock’s history, from the dawn of the nuclear age to new risks we face in the modern era.

When the Doomsday Clock debuted in 1947 as a cover design for the new magazine version of the newsletter-style Bulletin of the Atomic Scientists (BAS), the clock hand stood at seven minutes to midnight, indicating an urgent public threat from nuclear technology.

The hand’s position remained static until President Harry Truman confirmed in late 1949 that the Soviet Union had tested a nuclear device, thereby starting a global arms race. The BAS then hit upon the idea to use the clock as a real-time tool to inform the public about the state of global security. “The scientists who came up with the idea of moving the clock’s hand had forecast an arms race back in 1945,” said Kennette Benedict, executive director of the BAS. “They decided to move the hand forward as a way to sort of say, ‘Here we go.’” The clock has been a powerful symbol ever since.

The Doomsday Clock’s minute hand nearly brushed midnight in September 1953. The move happened after the United States and the Soviet Union each tested a thermonuclear device within a nine-month span.

“This demonstrated an acceleration of the arms race,” said Benedict, “and there was no communication between the two countries at all, even behind the scenes.”

To de-escalate the arms race and reduce the effects of excessive nuclear fallout on the environment, leaders from the three major nuclear powers—the United States, Great Britain and the Soviet Union—signed the Partial Test Ban Treaty, which prohibited above-ground nuclear testing, in August 1963.

In response, the Doomsday Clock’s hand moved comfortably away from midnight, conveying the Bulletin’s increased optimism.

With China and France obtaining nuclear capabilities, the U.S. war in Vietnam escalating, India and Pakistan at odds and renewed hostilities in the Middle East, the BAS lamented the state of global security by moving the Doomsday Clock hand forward to ring in January 1968.

“There is little reason to feel sanguine about the future of our society on the world scale,” the Bulletin proclaimed at the time.

After a decade of relative arms stability, the Cold War reached new heights between 1980 and 1983 as the Soviet Union invaded Afghanistan, the United States pulled out of the Moscow Olympics and communication between the two superpowers all but ceased.

The Bulletin took these as ominous signs and advanced the Doomsday Clock hand as close to midnight as it had stood since the arms race began in 1949.

Following the fall of the Berlin Wall in 1989 and the subsequent breakup of the Soviet Union, in 1991 the BAS took the exceptional step of holding a public symposium to discuss the meaning of these events and invite discussion about the state of global security in the aftermath of the Cold War.

“This was a time they literally went off the charts” in debating the position of the Doomsday Clock hand, Benedict said. Finally, in December 1991, after the United States and Russia signed the Strategic Arms Reduction Treaty and began slashing their nuclear arsenals, the Bulletin moved the clock hand 17 minutes away from midnight to reflect this unprecedented moment of peace and cooperation between the superpowers.

In 2007, the BAS broadened the scope of threats represented by the Doomsday Clock to include not only nuclear weapons but nuclear energy, climate change and “technologies not created with malice aforethought, like synthetic biology, but technologies that nonetheless could spell doom for civilization today,” Benedict said.

In placing the clock hand at five minutes to midnight in January 2012, the Bulletin cited “clear and present dangers of nuclear proliferation and climate change” as the motivation behind the move toward doomsday.