The Bulletin of Atomic Scientists raises concerns over "strident nationalism worldwide in 2016, including in a U.S. presidential campaign during which the eventual victor, Donald Trump, made disturbing comments about the use and proliferation of nuclear weapons and expressed disbelief in the overwhelming scientific consensus on climate change."

"The United States and Russia—which together possess more than 90 percent of the world’s nuclear weapons—remained at odds in a variety of theaters, from Syria to Ukraine to the borders of NATO," the report reads. "Both countries continued wide-ranging modernizations of their nuclear forces, and serious arms control negotiations were nowhere to be seen."

Read alsoKravchuk on nukes: If N.Korea can make them, Ukraine can, too (Video)For the last two years, the minute hand of the Doomsday Clock stayed set at three minutes before the hour, the closest it had been to midnight since the early 1980s.

Read alsoGlobal Times: China deploys intercontinental missiles near Russian borderIn its two most recent annual announcements on the Clock, the Science and Security Board warned: "The probability of global catastrophe is very high, and the actions needed to reduce the risks of disaster must be taken very soon."