The Doomsday Clock, maintained for the past 70 years by the Bulletin of the Atomic Scientists, has been moved to two and a half minutes from midnight following the election of Donald Trump.

The clock was originally set at seven minutes to midnight in 1947, but this was cut to two minutes in 1953 after the US and USSR tested hydrogen bombs within months of each other. Since then, it has risen as high as 17 minutes from doom in 1991, but the election of Donald Trump, the accelerating rate of climate change, and nuclear proliferation have all been cited as the reason for today's shift.

"The board's decision to move the clock less than a full minute – something it has never before done – reflects a simple reality: As this statement is issued, Donald Trump has been the US president only a matter of days," the report [PDF] states.

"He has made ill-considered comments about expanding the US nuclear arsenal. He has shown a troubling propensity to discount or outright reject expert advice related to international security, including the conclusions of intelligence experts. And his nominees to head the Energy Department and the Environmental Protection Agency dispute the basics of climate science."

It's not just the current occupant of the White House that is concerning scientists, but the other heads of state among the nuclear club members. Russia is upgrading its nuclear forces and building a new Borei Class of missile submarines, as well as rail-transported missiles.

China, meanwhile, is expanding its nuclear arsenal and is also helping Pakistan build submarine-based missile platforms. That's rather concerning, as the Bulletin notes that in December, Pakistan Defense Minister Khawaja Asif threatened Israel with nuclear retaliation after reading a fake news story that the Israelis were considering attacking Pakistani forces in Syria.

North Korea is also planning more nuclear tests and is reportedly creating an intercontinental missile to carry it, while President Trump has suggested that South Korea and Japan should acquire nukes in order to protect themselves. The president may also end the Iran nuclear deal, which the Bulletin says is working so far.

Climate change, and the American government's attitude to it, is also cited in the report. While last year's Paris agreement on emissions controls proved hopeful, the fact that one of the world's largest polluters now disputes the effects of carbon dioxide and other greenhouse gases is giving the scientists serious cause for concern.

More reliance on nuclear power could be a way out of this, the Bulletin notes, but many nuclear generating plants are reaching the end of their lives and to get a 6 per cent cut in greenhouse gas emissions, nuclear power would have to increase in capacity at least threefold during the next 50 years – the equivalent of a new 1 gigawatt-electric nuclear power plant every several weeks.

"It is two and a half minutes to midnight, the Clock is ticking, global danger looms," the report concludes. "Wise public officials should act immediately, guiding humanity away from the brink. If they do not, wise citizens must step forward and lead the way." ®