The Doomsday Clock which symbolises the current threat of global annihilation, was moved closer to midnight following a year of growing tensions between North Korea and the Donald Trump.
The countdown was established in 1947 by a group of experts who were working on the Manhattan Project, to design and build the first atomic bomb.
The scientists wanted a simple way of demonstrating how close humanity was to destroying the world with dangerous technologies of its own making.
Last year the Bulletin of the Atomic Scientists moved it forward by 30 seconds, to two and a half minutes to midnight, claiming the global security landscape had ‘darkened.’ But tensions between the US and North Korea have caused the hands to be moved forward again by 30 seconds.
The clock is now set at two minutes to midnight, the closest since 1953, when the US took the decision to upgrade its nuclear arsenal with the hydrogen bomb.
"It is with considerable concern that we set the Doomsday Clock, as of today," said Rachel Bronson, president and CEO of the organization.
"It is two minutes to midnight."
Time of the 2018 Doomsday Clock, as of today: It is 2 minutes to midnight. #turnbackthedoomsdayclock
— BulletinOfTheAtomic (@BulletinAtomic) January 25, 2018
The organisation now believes “the world is not only more dangerous now than it was a year ago. It is as threatening as it has been since World War II."
Earlier this month, Donald Trump taunted Kim Jong-un on Twitter claiming America’s nuclear ‘button’ is ‘much bigger and more powerful’ than that of the North Korean president.
In September, North Korea said that it considered the President's tweet that ‘Kim won’t be around much longer’ as a declaration of war. The country has also carried out several high-profile missile tests.
Bruce Blair, co-founder of Global Zero, the anti-nuclear campaigners, also warned that disaster was looming.
“2017 was a year of mounting insecurity across multiple nuclear flashpoints from Europe to Asia.
"The United States and Russia have worsened their already tense relationship with mutual allegations of cheating on the INF treaty. If this treaty falls apart it will stimulate nuclear arms racing in Europe.
"The gravest risk of all is the flashpoint on the Korean peninsula, which worsened considerably over Kim's long-rang missile and thermonuclear bomb test successes and Trump's response to launch a preventive conventional strike.
"We are on a collision course that could explode in early to mid 2018 and escalate quickly to nuclear conflict, and possibly draw China into the conflict.
"President Trump has been unable to provide the stable and solid leadership the world desperately needs to avoid conflict, and instead indulges in petulant nuclear brinksmanship. He also bombed the Paris accords devoted to reducing carbon emissions."
And Mr Blair said tensions existed elsewhere.
"South Asia is a nuclear flashpoint with escalating tensions over Kashmir," he added. "Both India and Pakistan are rapidly growing their nuclear arsenals. India is threatening to send troops into Pakistan if another lethal terrorist attack occurs on Indian soil, Pakistan is threatening to use nuclear weapons in response, and India says it is ready to call Pakistan's "bluff".
"The clock is currently set at 2.5 minutes to midnight. It should be moved forward by 1.5 minutes. It's now 1 minute to global catastrophe."
Editor and Chief of the Bulletin of Atomic Scientists John Mecklin said: "This danger looms at time when there has been a loss of trust in politics, media and facts themselves. The existential threats are ones of man's own making.
"We need to control the proliferation of cyber-weapons. We need to remake the infrastructure associated with the control."