Under the shadow of the Cold War, many in the world feared the impending prospect of a nuclear winter. According to a new report, our focus has since drifted from its horrors, leaving us with a general lack of awareness that could be dangerous for the future of humankind.

It goes without saying that the threat of a nuclear blast is no trivial event. Decades of pop culture have left society with a relatively strong association between global calamity and atomic weapons.

But the exact details on exactly what we might expect from such an escalating conflict have become hazy in the past few decades.

The facts themselves are fairly clear. Besides the many millions who would be killed directly from the blasts, climate models predict the debris resulting from nuclear war would block out much of our sunlight for up to a decade. The consequences for survivors would be devastating: a decline in global temperature, followed by widespread crop failure, and then mass starvation.

In spite of this dark threat, just a small percentage of today's population claim to be well informed about the precise consequences of a nuclear war – and many of those people are relying on outdated information spread amid the political tensions between superpowers in the 1980s.

"In 2023 we find ourselves facing a risk of nuclear conflict greater than we've seen since the early eighties," says Paul Ingram, a global risk researcher and diplomacy expert at the Centre for the Study of Existential Risk (CSER) run by the University of Cambridge in the UK. Ingram is the sole author of the report, which has not been peer reviewed.

"Yet there is little in the way of public knowledge or debate of the unimaginably dire long-term consequences of nuclear war for the planet and global populations."

An online poll of 1,500 people in the UK and 1,500 people in the US was used to prepare the new report. The participants were quizzed on how much they know about a potential nuclear winter, and where they had got their information from. The survey allowed multiple sources to be picked, so they're not mutually exclusive.

The results revealed 3.2 percent of UK respondents and 7.5 percent of US respondents had heard about the consequences of a nuclear war from contemporary media or culture. A greater fraction of people said their recollection of information spread in the 1980s, during a period of increasing hostility in the US-Soviet Union Cold War, informed their views of the risk of a nuclear winter. Unsurprisingly, few people relied on recent academic papers.

Using hypothetical news reports as a prompt, Ingram also looked at how people would want their governments to respond in the event of a nuclear strike. Half of those surveyed were shown infographics on the effects of nuclear winter before they answered, while the other half were not.

In the event of a nuclear attack on Ukraine from Russia, nearly one in five people involved in the study supported retaliation with nuclear weapons. For those who had seen the infographics ahead of time, that figure dropped by 13 percent in the UK and 16 percent in the US – showing how education makes a difference in public opinion.

"There is an urgent need for public education within all nuclear-armed states that is informed by the latest research," says Ingram. "We need to collectively reduce the temptation that leaders of nuclear-armed states might have to threaten or even use such weapons in support of military operations."

The nuclear winter infographics used by the researchers were published in a 2022 peer-reviewed study. The smallest nuclear war theorized involved 100 nukes of 15 kilotons each (about the same size used on Hiroshima), which represents just 0.1 percent of the total combined nuclear arsenal of Russia and the US.

That 'small' war would lead to 27 million direct fatalities and 225 million additional deaths from starvation, scientists calculate. At the top end of the scale, all-out nuclear war, we're looking at 400 million direct deaths and more than 5 billion people dying of starvation because of the consequences of nuclear war.

With so many factors to consider, estimates differ when it comes to the impact of a nuclear war – but even the best case scenarios will clearly be unimaginably terrible. What this report shows is that a big part of avoiding the self-destruction of our species is in raising awareness of what we might be about to do to ourselves.

"Ideas of nuclear winter are predominantly a lingering cultural memory, as if it is the stuff of history, rather than a horribly contemporary risk," says Ingram.

The report is available to read in full online at the Centre for the Study of Existential Risk.