The risk of civil collapse from nuclear weapons and the climate crisis is at a record high, according to US scientists and former officials, calling the current environment “profoundly unstable”.

Trump's impeachment lawyers 'tending toward conspiracy theories' says Schiff – live trial updates Read more

They said the rise of “cyber-enabled disinformation campaigns” compounds both threats by keeping the public from insisting on progress.

The Bulletin of the Atomic Scientists announced its symbolic “doomsday clock” has moved forward to 100 seconds to midnight, the closest to catastrophe that the scientists have judged the world to be at any point since its creation in 1947, at the outset of the cold war.

“The world needs to wake up. Our planet faces two simultaneous existential threats,” said Mary Robinson, chair of an independent group of global leaders called The Elders, and the former president of Ireland and former UN high commissioner of human rights.

Robinson said that countries that don’t aim to eliminate greenhouse gas emissions heating the planet and instead exploit fossil fuels are issuing “a death sentence for humanity”.

She said while public pressure presents a “sliver of hope” for the climate, there is no such pressure on leaders to avert nuclear threats.

As long as nuclear weapons are available it is inevitable they will one day be used, “by accident, miscalculation or design”, she said.

Robert Rosner, chair of the Bulletin’s science and security board, said society has normalized a very dangerous world, and that “information warfare” is undermining “the public’s ability to sort out what’s true and what’s patently false”.

Sharon Squassoni, a board member and research professor at George Washington University, noted the US withdrawal from the Iran nuclear agreement, which has resulted in Iran reducing compliance. And she said although some thought Donald Trump’s unique approach might bring North Korea to the negotiating table, no real progress has ensued.

The warning comes as nuclear arms control is in danger of dying out altogether. The Intermediate-range Nuclear Forces (INF) treaty lapsed in August after the US accused Russia of cheating and Donald Trump declared he would leave the 1987 treaty altogether. The US has begun testing medium-range missiles similar to the new Russian weapon, although it is unclear where in Europe or Asia they would be based.

The death of the INF leaves the New Start treaty as the last remaining limit on the US and Russian deployed strategic arsenals. It was agreed in 2010 by the then Russian president, Dmitry Medvedev, and Barack Obama, and it expires in February 2021.

It can be extended for five years and Vladimir Putin has said he is willing to agree an extension, but the Trump administration has insisted that China be included. China, whose arsenal is a 20th of the two nuclear superpowers and not as aggressively deployed, has ruled out joining in.

The farthest the doomsday clock has ever been from midnight was 17 minutes at the end of the cold war.

While nuclear warfare remains a threat, the climate crisis continues to intensify, as the US federal government under Trump has withdrawn from international climate efforts.

Last year was the second hottest on record for the Earth’s surface. The 2019 average temperature was 1.1C warmer than the average between 1850 and 1900, before the ramp-up of fossil fuel use. Greenhouse gas emissions from human activities are on track to push that warming to 3 or 4C. The disruptions are intensifying extreme weather and expected to exacerbate poverty and global unrest.

“If the Earth warms by what we tend to think of as just a few degrees and human life pushes the planet into the opposite of an Ice Age … or even pushes the climate halfway there, we have no reason to be confident that such a world will remain hospitable to human civilization,” said Sivan Kartha, a board member, senior scientist at the Stockholm Environment Institute and author of the fifth and sixth assessment reports of the Intergovernmental Panel on Climate Change.

Robert Latiff, a board member and retired air force major general, said the Trump administration’s “disdain for expert opinion” threatens action on climate change and a host of other science-based issues. New technologies and developments – from “deep fake” videos, to dangerous pathogens and artificial intelligence, all could threaten a fragile global peace.