Experts assessing the dangers posed to civilisation have added climate change to the prospect of nuclear annihilation as the greatest threats to humankind.
As a result, the group has moved the minute hand on its famous "Doomsday Clock" two minutes closer to midnight.
The concept timepiece, devised by the Bulletin of the Atomic Scientists, now stands at five minutes to the hour.
The clock was first featured by the magazine 60 years ago, shortly after the US dropped its A-bombs on Japan.
Not since the darkest days of the Cold War has the Bulletin, which covers global security issues, felt the need to place the minute hand so close to midnight. (more)