The huge flash of blinding light when a nuclear bomb detonates is ‘like bringing a piece of the sun down to the ground’ (Picture: Getty Images/iStockphoto)
An all-out nuclear war could wipe out hundreds of millions of people around the world within the space of just a few hours.
The huge flash of blinding light when one detonates is ‘like bringing a piece of the sun down to the ground’. Everything within the miles-wide firestorm is instantly incinerated.
Professor Brian Toon has spent decades studying the consequences of nuclear war on the climate – and his findings make for even more terrifying reading.
They show that the smoke from burning cities would block out the sun’s rays, plunging the world into a new horror called nuclear winter.
Professor Toon spoke to Metro about nuclear winter theory and why his warnings about it 40 years ago are still just as valid today.
What is nuclear winter?
Nuclear winter theory first caught the world’s attention in 1983 when one of the its most famous scientists, Carl Sagan, published an article asking ‘Would nuclear war be the end of the world?’.
In it, he wrote that ‘in a nuclear exchange more than a billion people would instantly be killed, but the long term consequences could be much worse’.
Sagan and some of his students, including Prof Toon, along with meteorologists subquently set out in horrifying detail what those consequences would be.
They found the thick black smoke billowing from burning cities and industrial areas would rise high up into the stratosphere and block out the sun’s light.
Brian Toon is professor of atmospheric and oceanic sciences at the University of Colorado Boulder (Picture: Edwina Hay)
The ensuing cold, dry and dark would send temperatures plummeting below zero and condemn billions more people to starvation with the collapse of agriculture.
The idea of mutually-assured destruction – if country A attacks country B, the retaliation by country B would render any first strike suicidal – has helped prevent nuclear war in the decades since.
But subsequent research also suggests it would be suicidal for country A to launch a first strike regardless of whether country B responds due to the climate changes caused by the smoke.
Faced with the poisoned apocalyptic world that would await any survivors of a full-scale nuclear war, former Soviet leader Nikita Khrushchev said: ‘The living will envy the dead.’
Would London be safe if World War III broke out?
‘Like bringing a piece of the sun down to Earth’
If you live in any big city across Europe or North America it’s safe to assume there is at least one nuclear bomb aimed at you right now.
Russia has around 2,000 strategic deployed nuclear weapons. The US has roughly the same.
Between them they have around 500 cities with more than 100,000 people – that’s eight nuclear bombs for each one.
‘It only takes one of those weapons to destroy a city with 100,000 people typically,’ Prof Toon says. ‘It’s overkill.
One nuclear bomb is enough to destroy a city of 100,000 people (Picture: Corbis via Getty Images)
‘If there’s a war between the US and Russia, Europe is going to be attacked, and it’s going to be attacked by nuclear weapons. It’s going to be attacked by a lot of nuclear weapons.’
He went on: ‘I recently looked at targets in Europe and I found about 650 military targets in Europe. Britain has them all over the place.’
The explosion from a nuclear bomb ‘is a lot like bringing a piece of the sun down to the ground’, Prof Toon says.
‘The bomb goes off, and there’s this huge energy release that creates an expanding fireball which is very hot. It’s initially in the millions of degrees but then soon reaches the temperature of the sun.
‘A typical nuclear weapon will destroy about a hundred square kilometres where it goes off, and most of that destruction occurs from the fires.
The mushroom cloud from Ivy Mike, one of the largest nuclear blasts ever (Picture: Corbis via Getty Images)
‘That’s what did the destruction in Hiroshima, for example, was fire. If you look at pictures of Hiroshima, there’s just rubble on the ground. A few standing concrete buildings still left.
‘And that damage was mostly from the fires.
‘In fact, for Hiroshima, the fires probably released a thousand times as much energy as the bomb itself, so they were very destructive.’
The blazes ignited by a nuclear bomb blast ‘are not normal fires’, Prof Toon says, adding: ‘It’s not just a little tiny place that is set on fire in an area – it could be 100 square kilometres – and a fire that big is going to have a smoke line that goes into the upper atmosphere.’
Mankind could go the same way as the dinosaurs
Not long before Prof Toon and his colleagues began their research it was discovered that an asteroid collision was responsible for killing the dinosaurs 66 million years ago.
There is a thin line of sediment left from the asteroid collision all over the planet.
‘That layer contains debris and rocks left from the asteroid,’ Prof Toon says. ‘Most of those look like little spheres that are about the size of a grain of sand.
‘They obviously were heated because they’re a spherical piece of rock, so we think the asteroid was vaporised when it hit the ground because of the huge energy release, which is the equivalent of a hundred million nuclear weapons going off.
‘It blew these little rock spheres all over the planet and when they re-entered the atmosphere they got hot because they were moving very fast and the friction with the air heated them up to a thousand or two thousand degrees centigrade.
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With the thousands and thousands of molten rocks raining down, the sky would have looked like a sheet of lava, Prof Toon says.
‘If you want to experience what the dinosaurs felt you can go down to the grocery store and buy a turkey, open up your oven and turn it to broil, then throw the turkey in there,’ he goes on.
‘That layer contains not just rock from Mexico and the asteroid, it also contains soot and smoke from the fire.
‘So you can see this 66 million-year-old debris left from the fire. And the amount of material there is so great that you had to burn everything on the surface of the earth.
‘That was all discovered in the early 1980s, and so we thought would this be similar to what would happen after a nuclear war when you get all these fires going in cities?’
Self-assured destruction
Back during the height of the Cold War, it was believed that any nuclear conflict was winnable.
But the modelling data suggested the opposite – for all sides and even some with no involvement in the conflict whatsoever.
Launch on warning
The United States has a launch on warning policy of nuclear weapon retaliation.
That means a retaliatory strike is launched upon warning of an enemy attack – it does not wait to absorb it.
Consequently, the US president is left with a desperately small window of time in which to decide how that retaliation will play out.
In her terrifying yet exhilarating book ‘Nuclear War: A Scenario’, award-winning investigative journalist and author Annie Jacobsen recounts Ronald Regan’s lament in his memoirs.
He wrote: ‘’Six minutes to decide how to respond to a blip on a radar scope and decide whether to release Armageddon! How could anyone apply reason to a time like that?’
Six minutes to weigh up the lives of millions, possibly billions of people.
‘The idea that we’re only a few hours away from the end of the world, that’s quite accurate in certain circumstances,’ Prof Toon says.
‘If you have a war between the United States and Russia and Europe and then possibly China, the amount of smoke there is so great that the sunlight has diminished to about 20% of normal over the planet,’ Prof Toon explains.
‘And these calculations with these climate models, the temperature falls below freezing.
‘So if you’re in a place like Ukraine, which is the bread basket of Europe, or Iowa, which is the bread basket of the US, the temperatures in those places fall below freezing within a few weeks of the war and stay below freezing continuously every day for a couple of years.
‘The actual minimum temperatures occur in about the third and fourth year, and it takes close to a decade to get back to normal temperatures.
‘You’re not going to grow anything at the temperatures below freezing every day for a couple of years. So there won’t be any food coming from the Middle Latitudes and that will create mass starvation.’
Ominously, he adds: ‘Starving doesn’t mean hungry – starving means dead.’
Where in the world could survive nuclear winter?
Prof Toon’s research has shown you might survive a nuclear war fought mainly in the northern hemisphere by living in Argentina, Australia or New Zealand.
Each are large food exporting countries, suggesting they would all be able to produce enough food to feed their current populations in the event all international trade in food were to collapse.
Even the worst case scenario in terms of smoke-induced climate change would be lessened there due to their locations in the southern hemisphere and being surrounded by large oceans.
Meanwhile, in the USA, Russia and China more than 90% of the populations there would perish from starvation.
Prof Toon helped coin the term self-assured destruction, arguing that the climate changes triggered by smoke from a nuclear first strike would be so damaging to food and water supplies, along with infrastructure breakdown, that starvation would occur in the attacking country as well as the nation targeted and countless others outside the combat zone.
Findings by he and his colleagues – backed by those of a team of Soviet scientists – helped persuade Mikhail Gorbachev and Ronald Reagan to reduce the number of warheads in 1986.
‘Both Gorbachev and Reagan said that their science communities told them that if they had a nuclear war, that it was going to kill everybody on the planet mostly,’ he says.
‘So, Reagan and Gorbachev agreed to get rid of nuclear weapons, delivery systems from short – range missile in Europe, and a build-down of nuclear weapons started to occur.
‘There were 70,000 nuclear weapons, now there’s around 10,000.’
Even a relatively ‘small’ nuclear war would be catastrophic
The US and Russia are not the only countries capable to wreaking climate havoc with nuclear war.
Each of the nuclear states – including the UK – with the exception of North Korea has enough firepower to alter the global climate.
‘I was called by somebody in the early 2000s because India and Pakistan had tested nuclear weapons and threatened each other for years over Kashmir,’ Prof Toon says.
‘The reporter asked what would happen if they had a nuclear war?’
He now regrets answering in haste that he believed it unlikely any consequences would stretch beyond those two countries.
Prof Toon went back and conducted simulations on a potential India-Pakistan conflict involving the use of roughly half their nuclear arsenals – 50 Hiroshima-size weapons.
‘Our best estimate at the moment is that if they used about half their arsenals they would kill something like 50 to 150 million people in India and Pakistan, and between one and two billion people over the rest of the planet,’ he added.
‘And the people over the rest of the planet would die because of nuclear winter.’
The current number of warheads per nuclear armed nation (Picture: Metro.co.uk)
‘We’re in a very dangerous period of time’
In 2018, Prof Toon gave a TED Talk titled ‘I’ve studied nuclear war for 35 years – you should be worried’.
Just before Russia waged war on Ukraine it had got around four million views. It now has nearly nine million.
Prof Toon says the comments have gone from ‘how can you study nuclear war for 35 years when there hasn’t been one?’ to ‘I’ve studied nuclear war for an hour and I’m worried about it’.
Asked whether the risk of nuclear war had ramped up along with the number of views, he says: ‘I think the risk has gone way up because of the Ukrainian war.
‘You’re now in a period of time where people have scenarios for how wars will start.
‘For example, the former leader of Estonia has a paper about how a nuclear war would start with the Russian invasion of Estonia and a NATO response to that.
‘Then that whole thing escalates because of some misunderstandings and nuclear war starts.
‘The whole Ukraine thing is one of your standard scenarios for how a nuclear war could start.
‘So we’re certainly in a very dangerous period of time.’
What is the most likely trigger for nuclear war?
Threats to unleash nuclear weapons have been coming from the Kremlin throughout Russia’s war on Ukraine and have ramped up once again in recent days.
But Prof Toon is not convinced Vladimir Putin is ‘irrational’ enough to follow through on them.
‘I’m pretty sure he understands that if he launched a nuclear war then that would be the end of Russia,’ he says.
‘I can imagine Russia becoming so frustrated with the war that they blow up a tactical weapon in Ukraine.
‘I don’t think that would have any real advantage in terms of the conflict because the troops there seem to be pretty dispersed – it’s not like there’s 100,000 troops sitting in one little place waiting to attack them.
‘The world has pretty well indicated to Putin that that is not acceptable, so it is hard to see that he would become so desperate as to do that. But I don’t know.
Vladimir Putin has repeatedly invoked the spectre of nuclear war (Picture: EPA)
‘There is a lot of concern over Donald Trump. When he left office a lot of people worried he might blow something up for the fun of it. It’s an open question as to how rational Donald Trump is.
‘But I don’t see any reason why he would start a nuclear war. Even he would realise that the response would be pretty bad.
‘So I think it’s most likely that it would start because of an accident and a misunderstanding between the two countries involved.
‘We’re in a heightened state of awareness right at this minute and we have been here for the last year or so.
‘There could be some kind of accident that occurs somewhere that could blow up and escalate.’
What can we do to eliminate the threat of nuclear winter?
Prof Toon says protest and letting politicians know how they feel is the way to get them to change.
‘That’s the only way it is going to go anywhere, is if people worldwide demand their politicians do something,’ he adds.
‘In democracies that’s practical. In Russia at the moment that’s probably very difficult to protest against nuclear weapons, so it varies across the world what you can do.
‘But people should attempt to make their politicians aware of this problem and do whatever they can to get them to do something about it.’
It worked with the Nuclear Test Ban Treaty in 1963 and again with Gorbachev and Reagan in 1986.
As they said in their joint statement: ‘Nuclear war cannot be won and must never be fought.’
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