Wars, climate change, disruptive technologies and the rise of autocracy over the past year prompted scientists to set the clock at 85 seconds to midnight.

The “Doomsday Clock,” which metaphorically rates how close humankind is to destroying itself, is now at 85 seconds to midnight, atomic scientists say.

Those factors include nuclear annihilation as well as climactic disasters; AI advancing faster than the ability to govern it; biological risks and spread of disease; the rise of autocracies; and proli...