Nuclear 'Doomsday Clock' ticks closest to midnight in 64 years

Lawrence Krauss (L), chairman of the 'Bulletin of the Atomic Scientists' Board of Sponsors, and board member Thomas Pickering (R), a former U.S. Under Secretary of State as well as US Ambassador to the United Nations, Russia and other countries, unveil that the board has moved the minute hand of their 'Doomsday Clock' by 30 seconds to a more ominous 2-1/2 minutes from midnight during a news conference at the National Press Club in Washington, U.S. January 26, 2017. REUTERS/Jim Bourg

Atomic scientists reset their symbolic "Doomsday Clock" to its closest time to midnight in 64 years on Thursday, saying the world was closer to catastrophe due to threats such as nuclear weapons, climate change and Donald Trump's election as U.S. president.

The timepiece, devised by the Chicago-based Bulletin of the Atomic Scientists and displayed on its website, is widely viewed as an indicator of the world's vulnerability to disaster.