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

The Bulletin of Atomic Scientists announced Tuesday that the "Doomsday Clock" is now set to 89 seconds to midnight.

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.