Inadequate progress on the reduction and proliferation of nuclear weapons, and the continuing inaction on climate change are cited as the reasons for the change.
The group also said the Fukushima power plant crisis highlighted the need to ensure nuclear energy is safe.
The Mayan 2012 Prophecy, however, was not among the reasons given.
The Doomsday Clock was created in 1947 and uses "the imagery of apocalypse (midnight) and the contemporary idiom of nuclear explosion (countdown to zero), to convey threats to humanity and the planet", the Bulletin said on its website.
The decision to move the minute hand is made by the Bulletin's board of directors in consultation with its board of sponsors, which includes 18 Nobel Laureates.
The last time the Doomsday Clock minute hand moved was in January last year, when the minute hand was pushed back one minute from five to six minutes before midnight.