The Chicago-based Bulletin of Atomic Scientists has moved the "Doomsday Clock," a symbolic countdown to the end of the world, to two and a half minutes to midnight. The setting is the closest the clock has come to midnight since 1953, when scientists moved it to two minutes from midnight after seeing both the U.S. and the Soviet Union test hydrogen bombs. The Bulletin of the Atomic Scientists said it made the decision based on the possible use of nuclear weapons, but includes climate change and technologies that could inflict irrevocable harm. The board criticized President Trump, saying that "even though he has just now taken office, the president's intemperate statements, lack of openness to expert advice, and questionable cabinet nominations have already made a bad international security situation worse."