doomsday clock

from the BBC:

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 Bulletin of the Atomic Scientists, founded by former Manhattan Project physicists, has campaigned for nuclear disarmament since 1947.
In the years ahead, rising sea levels, heat waves, desertification, along with new disease outbreaks and wars over arable land and water, would mean climate change could bring widespread destruction, the board said.
Over the past 60 years, the Doomsday clock has now moved backwards and forwards 18 times. It advanced to two minutes before midnight - its closest proximity to doom - in 1953 after the United States and the Soviet Union detonated hydrogen bombs.
Full story at BBC news.