(NewsNation) — The doomsday clock for 2024 was set at 90 seconds to midnight for a second year in a row Tuesday.

The clock isn’t a forecasting tool but a metaphor, according to the The Bulletin of the Atomic Scientists, which created it. It’s meant to warn the public about how close humanity is to destroying the world with “dangerous technologies of our own making,” according to the Bulletin, which calls the clock a “reminder of the perils we must address if we are to survive on the planet.”

90 seconds is the closest the clock’s ever been to midnight, or “doomsday.” Last year, scientists said the 2023 clock was set this way “largely, though not exclusively” due to the war in Ukraine.

This year, Bulletin president and CEO Rachel Bronson once again cited the war in Ukraine, but also the Oct.7 attack in Israel, and the country’s military offensive in Gaza; modernization programs that threaten to create a new nuclear arms race; and the Earth experiencing its hottest year on record, along with other climate disasters.

There are other factors, Bronson said, that raise questions. Biological research aimed to prevent future pandemics like COVID-19 is useful, but also heighten the risk of causing one. she said. In addition, recent advances in Artificial Intelligence could pose issues on how to control technology that could improve or “threaten” society, Bronson said.

“The risks of last year continue with unabated ferocity and continue to shape this year today we once again set the doomsday clock to express a continuing and unprecedented level of risk,” Bronson said Tuesday.

A group of international nuclear risk, climate change, disruptive technologies and biosecurity experts on the Bulletin’s Science and Security Board is responsible for setting the clock.

Created in 1947, the clock was originally set to seven minutes to midnight. The clock was first reset to three minutes in 1949 after the Soviet Union successfully tested its first atomic bomb.