The Doomsday Clock is a symbolic timepiece showing how close we are to ‘destroying our world with dangerous technologies of our own making’.

For the first time in three years, the Bulletin of the Atomic Scientists (BAS) moved the Doomsday Clock forward by one second to 89 seconds before midnight, signalling a heightened risk of global catastrophe.

“It is the determination of the science and security board of the Bulletin of Atomic Scientists that the world has not made sufficient progress on existential risks threatening all of humanity. We thus move the clock forward,” Daniel Holz, chair of the organisation’s science and security board, said during a livestreamed event on Tuesday.

Ongoing threats from nuclear weapons, climate change, bioweapons, infectious disease, and disruptive technologies like artificial intelligence (AI) have brought the clock to its latest time in 78 years.

What is the Doomsday Clock?

The Doomsday Clock is a symbolic timepiece showing how close we are to “destroying our world with dangerous technologies of our own making”, according to BAS, a Chicago-based nonprofit organisation that controls the clock.

It describes it as “many things all at once: It’s a metaphor, it’s a logo, it’s a brand, and it’s one of the most recognisable symbols in the past 100 years.”

The closer it moves to midnight, the closer humanity is to the end of the world.

Apocalyptic threats could arise from political tensions, weapons, technology, climate change or pandemics.

How is the clock set?

The hands of the clock are moved closer to or farther away from midnight based on the scientists’ reading of existential threats at a particular time.

BAS updates the time annually. A board of scientists and other experts in nuclear technology and climate science, including 10 Nobel laureates, discuss world events and determine where to place the hands of the clock each year.

“The Bulletin is a bit like a doctor making a diagnosis,” the BAS website says.

“We look at data, as physicians look at lab tests and x-rays, and also take harder-to-quantify factors into account, as physicians do when talking with patients and family members. We consider as many symptoms, measurements, and circumstances as we can. Then we come to a judgment that sums up what could happen if leaders and citizens don’t take action to treat the conditions,” it adds.

Has the clock ever turned back?

Yes, the most notable event was in 1991 when US President George HW Bush and Soviet leader Mikhail Gorbachev signed the Strategic Arms Reduction Treaty (START) to reduce the number of their countries’ nuclear weapons and ballistic missiles.

This brought the clock back by seven seconds. The furthest the clock has been from midnight was 17 minutes.

When was the Doomsday Clock created?

The clock was created in 1947 by the Bulletin of the Atomic Scientists, which was founded two years earlier by scientists Albert Einstein, J Robert Oppenheimer and Eugene Rabinowitch along with University of Chicago scholars.

During that time, the clock was set at seven minutes to midnight. But after the Soviet Union successfully tested its first atomic bomb in 1949, Rabinowitch, who was then the bulletin’s editor, moved the clock to three minutes to midnight.

According to the University of Chicago, until recently, the closest it had ever been set was at two minutes to midnight: in 1953 when the US and the Soviet Union tested thermonuclear weapons and in 2018 because of “a breakdown in the international order, of nuclear actors, as well as the continuing lack of action on climate change”.

The Doomsday Clock is placed in the BAS offices at the University of Chicago.