The Bulletin of the Atomic Scientists is moving the Doomsday Clock up to 100 seconds to midnight - a metaphor for the end of the world - in a recognition of growing threats from nuclear war, climate change and disinformation.

The clock had been at two minutes to midnight since 2018. Now, the looming dangers are captured in a smaller unit in a testament to the need for urgent action, the Bulletin said Thursday, as its president warned of influential leaders who "denigrate and discard the most effective methods for addressing complex threats."

The latest jump closer to midnight "signals really bad news," said astrophysicist Robert Rosner, part of the Bulletin's Science and Security Board. "What we said last year is now a disturbing reality in that things are not getting better."

The group's reasoning has traditionally focused on the availability of nuclear weapons and a willingness among the world's great powers to use them, and members of the Bulletin's Science and Security Board pointed this year to a host of concerning developments - including the prospect of a deal limiting Iran's nuclear development completely falling apart, after Iran began reducing its compliance following the U.S.'s withdrawal under President Trump.

In North Korea, meanwhile, there's been "no real progress" despite fanfare over talks, said Sharon Squassoni, a professor at George Washington University and Science and Security Board member. And North Korean leader Kim Jong Un has promised to demonstrate a new weapon.

Thursday's announcement also underscored changes over the years in the threats tracked by the Doomsday Clock, as the Bulletin's scientists express growing concern about the state of the planet. They warned in 2007 that the threat of climate change is "nearly as dire" as the dangers of nuclear weapons.

And those twin problems "are compounded by a threat multiplier, cyber-enabled information warfare, that undercuts society's ability to respond," the Bulletin said in its statement this year. It said many governments have used disinformation campaigns over the last year to "sow distrust in institutions and among nations."

"The international security situation is dire, not just because these threats exist, but because world leaders have allowed the international political infrastructure for managing them to erode," the group warned.

Former California governor Jerry Brown, the Bulletin's executive chair, emphasized the confluence of concerns in a statement.

"Dangerous rivalry and hostility among the superpowers increases the likelihood of nuclear blunder," he said. "Climate change just compounds the crisis. If there's ever a time to wake up, it's now."

The clock, a metaphorical measure for humankind's proximity to destruction, has wavered between two and 17 minutes to the apocalypse since its inception in 1947.

The Bulletin of the Atomic Scientists was founded by veterans of the Manhattan Project who were concerned about the consequences of their nuclear research. One of them, nuclear physicist Alexander Langsdorf, was married to artist Martyl Langsdorf, who created the clock and set it at seven minutes to midnight, or 11:53, for the cover of the group's magazine. Her husband moved the time four minutes ahead in 1949.

Since then, the Bulletin's board has determined how far the clock's minute hand will move, usually to draw attention to worldwide crises that it believes threaten the survival of the human species.

Last year, the clock didn't budge, remaining at two minutes to "midnight" after advancing 30 seconds in 2018. It had also advanced 30 seconds in 2017 but did not move at all in 2016.

The decision to move up the time on the clock in 2018 was motivated largely by the Bulletin's sense of looming nuclear peril. It listed a series of grim developments: North Korea had made rapid progress in developing a thermonuclear weapon capable of reaching the United States. Relations between the United States and Russia had deteriorated, with no high-level arms-control negotiations happening between the two countries. And nations around the world were moving to modernize and enhance their nuclear arsenals.

In addition, the organization cited unchecked artificial intelligence, the alarming spread of disinformation and the public's eroding trust in institutions.

The group said last year that although the scientists noted an upsetting change in the information ecosystem in 2018, they did not see a "qualitative" change with other threats that would have warranted resetting the time on the clock.

But Bulletin President Rachel Bronson told reporters that the clock’s lack of movement reflected a “new abnormal” and “should not be taken as a sign of stability but as a stark warning.”