CHICAGO (CBS) — The ‘Doomsday Clock’ was moved up 30 seconds and is now set at two minutes to midnight, equaling the most dangerous setting in the history of the clock.

The Bulletin of Atomic Scientists, which is based at the University of Chicago, made the announcement on Thursday in Washington, D.C.

Only once in the 71 year history of the clock, has it been set at two minutes to midnight. That was as the height of the Cold War in 1953.

The group cited increased tensions with North Korea over nuclear weapons and the impact of climate change.

North Korea has conducted a series of tests that show alarming progress in its nuclear weapons capability in the past year.

Each year – and at key moments in history – scientists have moved the Doomsday Clock’s minute hand closer to or further from midnight, to represent the seriousness of global safety.

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