The Bulletin of the Atomic Scientists has taken the unprecedented step of moving the Doomsday Clock ahead 30 seconds, taking the world to 2½ minutes to midnight.
The scientists said Thursday that several factors weighed heavily in their decision, particularly climate change denial by people in power — they cited U.S. President Donald Trump — and talk about more nuclear weapons.
"This is the first time the words and stated policy of one or two people placed in high positions has had such an impact to our perception of existential threat," said scientist Lawrence Krauss.
In 1953, as a result of the first detonation of a nuclear bomb by the U.S., the clock moved to two minutes to midnight, the closest it has ever been.
THIS IS A BREAKING NEWS UPDATE. EARLIER STORY BELOW.
Will it move forward, backward or remain the same?
The Bulletin of the Atomic Scientists will announce the status of the famous Doomsday Clock, used since 1947 to measure how close humans are to destroying our civilization.
Thursday's announcement will come at 10 a.m. ET.
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In 2015, the clock moved to three minutes to midnight, ahead from five minutes set in 2012.
At the time, the group of scientists said:
"Unchecked climate change, global nuclear weapons modernizations, and outsized nuclear weapons arsenals pose extraordinary and undeniable threats to the continued existence of humanity, and world leaders have failed to act with the speed or on the scale required to protect citizens from potential catastrophe. These failures of political leadership endanger every person on Earth."
The clock remained at three minutes to midnight in 2016.
"Factors influencing the 2017 deliberations regarding any adjustment that may be made to the Doomsday Clock include: a rise in strident nationalism worldwide, President Donald Trump's comments on nuclear arms and climate issues prior to his inauguration on January 20th, a darkening global security landscape that is coloured by increasingly sophisticated technology, and a growing disregard for scientific expertise," the Bulletin of Atomic Scientists said in its announcement ahead of the event.
Since its inception, the clock has moved ahead only 19 times. The last time the clock was moved to three minutes to midnight was in 1983, at the height of tense U.S.-Soviet Union relation