Scientists have set the so-called Doomsday Clock closer to midnight, highlighting what they perceive to be heightened dangers and increased probability of global disaster. The Bulletin of Atomic Scientists announced Tuesday they have moved the minute hand on their clock to 89 seconds to midnight. Scientists citing Russian nuclear threats, other world conflicts, artificial intelligence and climate change as factors underlying the risks of global catastrophe. The Bulletin, a Chicago-based nonprofit, created the clock in 1947 during the Cold War tensions that followed World War Two. We spoke with Dr. Herbert Lin, a member of the Science and Security Board of the Bulletin of Atomic Scientists and senior researcher at Stanford University.