WASHINGTON: The symbolic “Doomsday Clock” was reset to 90 seconds to midnight on Tuesday, reflecting existential threats to humanity posed by potential nuclear escalation from the Ukraine conflict and the multiplying impacts of the climate crisis following Earth’s hottest recorded year.

Set by top scientists and security experts, the timing of the clock remains the same as last year and the closest it has ever been to midnight in its more than 75-year-history.

“Trends continue to point ominously towards global catastrophe,” said Rachel Bronson, president and CEO of the Bulletin of Atomic Scientists. “The war in Ukraine poses an ever present risk of nuclear escalation, and the October 7 attack in Israel and war in Gaza provides further illustration of the horrors of modern war, even without nuclear escalation.

Rather than abandoning nuclear weapons, countries that possess them are upgrading their arsenals and threatening to create a new arms race, while massive floods, fires and other disasters marked the hottest year on record by far, with little meaningful action on climate change.

“Biological research aimed at preventing future pandemics has proven useful, but also presents the risks of causing one,” she said, while recent advances in artificial intelligence (AI) raise questions about how to control a technology “that could improve or threaten civilization in countless ways.”

The clock was originally set at seven minutes to midnight.

The furthest from midnight it has ever been is 17 minutes, following the end of the Cold War in 1991.