At the dawn of the nuclear age, scientists created the Doomsday Clock as a symbolic representation of how close humanity is to destroying the world. On Tuesday, nearly eight decades later, the clock was set at 85 seconds to midnight — the closest the timepiece has ever been to midnight, according to the Bulletin of the Atomic Scientists, which established the clock in 1947.
Midnight represents the moment at which people will have made Earth uninhabitable.
Last year, the Bulletin set the clock at 89 seconds to midnight, which was, at that point, the closest the world had ever been to that hour. After setting the clock at 90 seconds to midnight in 2023 and 2024, the scientists made the 2025 change due to insufficient progress in combatting or regulating global challenges including nuclear risk, the climate crisis, biological threats, and advances in “disruptive technologies” such as artificial intelligence. Bulletin scientists also cited the spread of misinformation, disinformation and conspiracy theories as other existential threats to humanity.
“Humanity has not made sufficient progress on the existential risks that endanger us all,” said Bulletin President and CEO Alexandra Bell of the reasoning for this year’s change. “The Doomsday Clock is a tool for communicating how close we are to destroying the world with technologies of our own making. The risks we face from nuclear weapons, climate change and disruptive technologies are all growing. Every second counts and we are running out of time.
“It is a hard truth, but this is our reality,” Bell said.
A group of scientists who worked on the Manhattan Project, the code name for the development of the atomic bomb during World War II, established the Bulletin of the Atomic Scientists as a nonprofit in 1945.
The organization’s original purpose was to measure nuclear threats, but in 2007, the Bulletin decided to also include the climate crisis in its calculations.
Annually over the past 79 years, Bulletin scientists have changed the clock’s time according to how close they believe the human race is to total annihilation. Some years the time changes, and some years it doesn’t. The time is set by experts on the Bulletin’s science and security board in consultation with its board of sponsors — which was formed by Albert Einstein in December 1948, with J. Robert Oppenheimer as its first chair. The board currently includes eight Nobel laureates, many of them in physics or chemistry.
The clock isn’t designed to definitively measure existential threats but rather to spark conversations about difficult scientific topics and crises the planet is facing, according to the Bulletin. Some experts who haven’t been involved in the clock’s designation have questioned its usefulness.
“It’s an imperfect metaphor,” Dr. Michael Mann, Presidential Distinguished Professor in the department of Earth and environmental science at the University of Pennsylvania, told CNN in 2022, highlighting that the clock’s framing combines various types of risk that have different characteristics and occur in different timescales. Still, he added that it “remains an important rhetorical device that reminds us, year after year, of the tenuousness of our current existence on this planet.”
The Bulletin has made thoughtful decisions each year on how to get people’s attention about existential threats and the required action, Eryn MacDonald, senior analyst with the Union of Concerned Scientists’ Global Security Program, told CNN in 2022. “While I wish we could go back to talking about minutes to midnight instead of seconds, unfortunately that no longer reflects reality.”
At the UN Climate Change Conference in Glasgow, Scotland, in 2021, then-UK Prime Minister Boris Johnson cited the Doomsday Clock when talking about the climate crisis the world is facing.
The Doomsday Clock has never reached midnight, and former Bulletin president and CEO Rachel Bronson, who now serves as a senior adviser, has said she hopes it never will.
“When the clock is at midnight, that means there’s been some sort of nuclear exchange or catastrophic climate change that’s wiped out humanity,” she said. “We never really want to get there, and we won’t know it when we do.”
Moving the Doomsday Clock back with bold, substantial actions is still possible. In fact, the hand moved its farthest away from midnight — 17 minutes to the hour — in 1991, when then-President George H.W. Bush’s administration signed the Strategic Arms Reduction Treaty with the Soviet Union.
“We at the Bulletin believe that because humans created these threats, we can reduce them,” Bronson said. “But doing so is not easy, nor has it ever been. And it requires serious work and global engagement at all levels of society.”
Regarding what individuals can do, don’t underestimate the power of discussing these important issues with your peers, Bronson said, adding that public engagement can urge leaders to act.
Other personal actions can also make a difference. To potentially help mitigate the climate crisis, for one, consider whether there are small changes you can make in your daily life, such as how often you walk versus drive and how you heat your home.
Eating seasonally and locally, reducing food waste, conserving water, reducing plastic use and recycling properly are other ways to help mitigate, or deal with the effects of, the climate crisis.
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