Doomsday Clock set to 100 seconds from midnight

The Doomsday Clock was set Thursday to 100 seconds from midnight — the closest it has ever been to mankind's metaphorical destruction since its creation in 1947 — due to the growing threat of climate change and looming threat of nuclear war, according to the Bulletin of the Atomic Scientists' Science and Security Board.

What they're saying: The board shifted the clock ahead 20 seconds — its first change in seconds, instead of minutes — "to underscore the need for action." Its executive chairman, former California Gov. Jerry Brown, said, "Dangerous rivalry and hostility among the superpowers increases the likelihood of nuclear blunder. Climate change just compounds the crisis. If there's ever a time to wake up, it's now."

Go deeper: Doomsday Clock remains at 2 minutes to midnight