Artificial intelligence was not listed as a chief concern two years ago, the last time the Bulletin of the Atomic Scientists moved the clock closer to global catastrophe.

The Doomsday Clock now stands at 89 seconds to midnight, the closest to catastrophe in its nearly eight-decade history. Here's a look at how — and why — it's moved.

As the Doomsday Clock ticks dangerously close to midnight, humanity faces escalating nuclear threats, climate disasters, and tech-driven risks.