Would Humans Survive a Nuclear War?

The prospect of a nuclear war is a terrifying one, and for good reason. The overwhelming majority of the human population would suffer extremely unpleasant deaths from burns, radiation, and hunger, and human civilization would likely collapse completely. Survivors would be left to earn a living on a devastated and barren planet. Estimates suggest that a large-scale nuclear war would directly kill 770 million people and produce 180 Tg of soot from the burning of cities and forests.

In the United States, approximately half of the population would be within 5 km of a zero nuclear explosion, and one-fifth of the country's population would die instantly. Decades of living with nuclear weapons have produced a wide body of knowledge about what a nuclear war could do to the planet and to humanity. If a small nuclear war broke out, tens of millions of people would die after the initial explosions. A blanket of soot would envelop the Sun's rays and cause a nuclear winter, destroying crops across the planet and plunging billions of people into famine. In the Northern Hemisphere, there would be such severe ozone depletion due to nuclear smoke that organisms would suffer greater exposure to harmful ultraviolet light. Even well-positioned countries like Australia in the Southern Hemisphere would face the ripple effects of a small nuclear war in the Northern Hemisphere due to their interconnection with the world community.

Those who survive the bombing and its effects will have to walk through burning rubble and pass through charred and lifeless bodies to safety. Some will ultimately survive, but others will succumb to injuries sustained or radiation. The wind will carry irradiated debris and objects known as rain, making many others sick. The consequences of a nuclear war would extend far beyond the explosion itself, killing millions of people around the world. With advances in nuclear technology since then, it is possible that the devastation of the next nuclear attack will be much worse.

Before the war in Ukraine, it seemed highly unlikely that the superpowers would reengage and wield nuclear weapons, so many scientists studied the effects of more limited nuclear conflicts. In 1982, nuclear disarmament activist Jonathan Schell published The Fate of the Earth, which many consider to be the first carefully argued presentation that concludes that extinction is a significant possibility of nuclear war. So what is the risk of nuclear war really? After talking to more than a dozen experts familiar with the horrors of nuclear conflicts, it appears that while possibilities are small, they are still present. In contrast to previous research on global nuclear conflicts, studies have shown that even small-scale regional nuclear conflicts could disrupt the global climate for a decade or more. Russian President Vladimir Putin has hinted that he would consider using nuclear weapons if faced with a NATO military response in Ukraine or if there was a direct threat to his person or regime. Scientists have argued that even a small-scale nuclear war between two countries could have devastating global consequences and such local conflicts are more likely than large-scale nuclear war. As a result of the extensive nuclear fallout from Castle Bravo in 1954, author Nevil Shute wrote the popular novel On The Beach released in 1957. While physical effects of a nuclear winter would begin to dissipate after a decade as the sky began to clear, catastrophic consequences of even localized nuclear conflict would have far-reaching effects. This report was made when nuclear stocks were at much higher levels than they are today but before risk of a nuclear winter was first theorized in early 1980s.

If you get an alert about an ICBM or other nuclear threat, here's how to act and where to take refuge. The term 'nuclear winter' was coined in 1980s when scientists began to realize that horrors of nuclear war would not be limited to explosive explosions and radiation. In a scenario involving 4,400 warheads and 150 Tg of soot, within five years of a nuclear war average reduction in dietary calories would be 97.2% in China, 97.5% in France, 99.7% in Russia, 99.5% in United Kingdom and 98.9% in United States. Depending on plan chosen by president command will go to US crews operating submarines carrying nuclear missiles, combat aircraft capable of launching nuclear bombs or troops supervising intercontinental ballistic missiles on ground. The risk of nuclear war is real but thankfully small; however, even small-scale regional conflicts could disrupt global climate for decade or more. It is important for people to know what steps they can take if they receive an alert about an ICBM or other nuclear threat.

Knowing how to act can help save lives if such an event were ever to occur.