Citing a rise in global nationalism and humanity’s failure to confront nuclear weapons and climate change, scientists today pushed the infamous Doomsday Clock 30 seconds closer to midnight—the symbolic moment humankind is supposed to annihilate itself. That pushes the planet from 3 minutes to destruction to a mere 2.5. Since the clock was launched in 1947, this is the closest we’ve come to the brink since 1953, when the Science and Security Board of the Bulletin of the Atomic Scientists ( BAS ) moved the hand 2 minutes to midnight following the first testing of a hydrogen bomb.

One of the biggest reasons for the move, wrote BAS scientists in an op-ed in The New York Times, was the ascent of U.S. President Donald Trump: “Never before has the Bulletin decided to advance the clock largely because of the statements of a single person,” they wrote. “But Mr. Trump’s statements and actions have been unsettling.”

Those include comments about the use of nuclear weapons during his campaign as well as during his transition to the White House. In a tweet in December 2016, Trump wrote, “The United States must greatly strengthen and expand its nuclear capability until such time as the world comes to its senses regarding nukes.” Politico reported he has since given mixed responses regarding the notion, saying “there is not going to be an arms race” but also noting he won’t “take anything off the table.”

“The world is a more dangerous place,” said Lawrence Krauss of Arizona State University in Tempe, who is a theoretical physicist and chair of the BAS Board of Sponsors, adding that BAS ’s Science and Security Board wanted to “send a [cautionary] message” 6 days into an administration that the group says shows “a growing disregard for scientific expertise.”

A panel of three BAS scientists and a former U.S. ambassador made the announcement, speaking not only of the new U.S. administration, but also about actions to develop nuclear weapons around the globe, including places like North Korea, India, Pakistan, China, and Russia. “It is not time to build up. It is time to continue to build down,” former U.S. Ambassador to the United Nations Thomas Pickering said when asked about U.S. and Russian nuclear capabilities, which now account for 90% of the world’s nuclear arms.

Panelists also expressed concern over the rise of fake news and general distrust of fact, both of which influenced the incremental move. “The Bulletin felt it was important to say ‘words do matter.’ This half-minute move was something we felt very strong and comfortable with because it represented a new set of figures we hadn’t confronted before,” Rachel Bronson, BAS executive director and publisher in Chicago, Illinois, said.

The threat of climate change and mixed efforts to reduce greenhouse gas emissions were also taken into account. Though advances were made with the Paris climate agreement, the panel said, it is too early to say whether they will bear out.

The apocalyptic clock was created by former Manhattan Project scientists in an effort to bring public attention to the threat of nuclear war. Hovering anywhere between 17 and 2 minutes to midnight since its formation, the minute hand of the clock advances forward to symbolize humanity’s looming demise.

Here’s a breakdown of every change for the last 60 years: