- Shuntaro Hida has been an anti-nuclear advocate since seeing Hiroshima destroyed.
- Modern nuclear weapons are orders of magnitude more powerful than the Hiroshima bomb.
- Carl Sagan, Richard Turco and colleagues described nuclear winter in 1983.
- A small percentage of the world’s nuclear warheads would cause a global catastrophe.
I saw a very strong light that could make my eyes blind and the core of my head all blank and white, and at the same time I felt burning hot all over the place which was exposed, not covered by the shirt…wind came maybe three, four seconds after…I looked up and what I saw was this mushroom cloud being formed. It was a clear day so I saw it very clearly.
At one o’clock the morning of 6th August 1945, he’d been called out of a boozing session at the Hiroshima hospital to attend a sick child in a nearby village. He sobered up on the back of a bicycle and was attending the boy when the world changed. Hida had just witnessed the second nuclear explosion the world had ever seen. Had it not been for the sick boy, he would have been part of that cloud.
Hida hurried back toward the hospital where he usually worked, expecting he would be needed to treat casualties. He didn’t know the hospital had been within a few hundred metres of the inexplicably enormous explosion.
I thought this is a human
The most remarkable thing about Hida’s story, told in an interview for BBC radio 4 and repeated in a briefer televised version, was what he didn’t say: having just become one of the first people to witness a nuclear explosion at close quarters, his reaction was to run
into the looming mushroom cloud to try to help the casualties.
I saw something weird, something strange, something black approaching me and there was a head, shoulder and legs so I thought this a human but it was all black so she came in front of me and she fell down towards me and died.
It was the first time Hida set eyes on the Hibakusha, as people injured by the atomic bombing of Hiroshima and a week later, Nagasaki, would become known. That day, he would start the caring for the Hibakusha that would become his life’s work. Initially, he could do no more than try to make people as comfortable as possible as they died. He had no medications, surgical tools or even bandages. It took him months before he persuaded General Douglas MacArthur, then commanding the American occupation forces in Japan, to grant him a building to use as a clinic. By then, Hida knew as much as anyone in the world about treating acute radiation exposure. His patients were losing their hair, unable to keep food down, anaemic and in many cases simply dying. The American occupiers didn’t want to hear about it, and they certainly didn’t want anyone else to hear about it. Hida was arrested several times as part of the effort to cover it up.
Hida is a very difficult man to shut up. Aged 99, he is still campaigning against nuclear weapons and nuclear energy.
The shadow of the bomb
That white light changed the way we all view the world. It wasn’t only the scale of the devastation that made such an impression; a few months earlier, the ‘Operation Meetinghouse’ air raid on Tokyo had killed more people in one night, and Tokyo was bombed regularly until the day Japan capitulated. It was that the devastation could be caused by a single aircraft carrying a single bomb.
As the Cold War gathered momentum and the USA and USSR ploughed resources into their ballistic missile programs, they didn’t even need aircraft. Nuclear warheads could be mounted on ballistic missiles and fired halfway round the world in under an hour. There is at least a chance of intercepting an aircraft carrying a bomb, but there is still no way of intercepting a ballistic missile.What is often overlooked is that the nuclear bombs dropped on Japan look like party poppers compared to some of the weapons in today’s nuclear arsenals. The explosion Hida witnessed was around 15kt (kilotons), meaning equivalent to 15,000 tons of TNT. The bomb dropped on Nagasaki was 20kt. Compare that to the 340kt W78 warhead currently strapped to the top of American Minuteman-III missiles, or the warheads for the Russian SS-18, which can be as large as 20Mt (megatons): more than a thousand times more powerful than the Hiroshima bomb.
For decades, we lived ‘in the shadow of the bomb’, to use an oft-spoken phrase. We knew that the USA and USSR were engaged in a nuclear standoff, and that we would get next to no warning if the doctrine of mutually assured destruction, aptly abbreviated to MAD, failed. Missiles launched between the two principals would take around 30min to reach their targets. In Britain, we knew that we had just enough nuclear weapons of our own to make us a target and at most, seven minutes’ warning if the button was pressed. We didn’t bother with the ‘duck and cover’ exercises practised in the USA. We wouldn’t even have time for that.
One man who was scathing about the accumulation of nuclear weapons was astronomer, physicist and author Carl Sagan. In a 1991 interview with C-Span, he identified three looming global catastrophes: ozone depletion, the greenhouse effect (now better known as global warming) and nuclear winter:
Looking back on it, the good news is that thanks to an unprecedented success of international co-operation, the ozone layer is slowly repairing itself. The bad news is that the greenhouse effect continues unabated and, more pertinently to the theme of nuclear weapons, the current presidents of Russia and the USA are both talking in terms of improving rather than depleting their nuclear arsenals.
Sagan, along with atmospheric scientist Richard Turco, had led much of the research leading to an understanding of nuclear winter. They came to it sideways from research on the way that dust in the atmosphere of Mars blocks sunlight from reaching the surface. At the time, Luis and Walter Alvarez had recently theorised that the dinosaurs were wiped out by a dust cloud thrown up by a meteor impact. Sagan, Turco and their colleagues reasoned that if a meteor could cause a global dust cloud, so could a nuclear explosion. They couldn’t stage a nuclear war to see what would happen, but they had plenty of information from nuclear tests to base a predictive model on.
Their findings, published in a 1983 paper in Science, make for chilling reading. The effects
of nuclear bombs exploding over cities were bad enough:
A 100kt airburst can level and burn an area of ≃50 km2, and a 1-MT airburst, 5 times that area.
To put it another way, the 100kt bomb could blast Paris to dust with a few kilotons to spare and still look feeble compared to its 1Mt big brother, which was far from the largest weapon in service.
Dust and smoke
The paper focused less on the devastation from the explosions, which was already understood, than on what would happen to the dust forming the mushroom clouds so emblematic of the nuclear age. A 1Mt blast throws up between 10,000 and 60,000 tons of the stuff and they anticipated that a small nuclear exchange would amount to around 3,000 such blasts. Dust would be blasted as high as 30km, well into the stratosphere, where it would disperse through the jetstreams. Once up there, the dust cloud would absorb and reflect sunlight, preventing it from reaching the earth’s surface.
Added to the dust would be plumes of smoke from firestorms blazing in any part of a city where there was enough left to burn. Because many of the nuclear targets were military bases outside cities, a nuclear war would start massive fires in forests and grasslands, pumping yet more smoke into the atmosphere.
The average surface temperature would drop by some 20-25°C (35-80°F) in the weeks following the war. That’s an average drop, and living close to the sea would reduce the effect to some extent because of the very high thermal capacity of the oceans: it takes avery long time for temperature changes in the sea to catch up with temperature changes in the atmosphere. The model assumes a nuclear war would be in the Northern hemisphere, so the effect on the Southern hemisphere would take longer to arrive and would be less serious, but would be substantial once it arrived.
As important as the temperature drop would be the loss of light reaching the surface. Without sunlight, plant growth would slow down and agriculture would collapse. For many of the survivors of the nuclear holocaust, the reprieve would be short lived. They would die of cold or starvation within a few months.
Most of the dust would fall to earth in a few months. The worst of the nuclear winter would be over, though it would take years for temperatures to return to the pre-war levels. The settling dust would bring another problem: much of it would be radioactive. Quite how radioactive is difficult to quantify. Modern nuclear weapons are much ‘cleaner’ than the Hiroshima and Nagasaki bombs because much of the yield is derived from nuclear fusion rather than nuclear fission. On the other hand, they are much more powerful so a small percentage of fission-derived yield still adds up to a lot of radioactivity.
The dust would settle on the skin of anyone still alive. They would breathe it in the air and ingest it in their food. Sagan and his colleagues estimated that it wouldn’t be enough to cause the acute radiation sickness that Hida found himself dealing with, but it would be enough to make an early death from cancer very likely.The nuclear winter ensures that a nuclear war will not only be devastating for the countries hit by nuclear weapons, but will cause a global apocalypse. ‘Mutually assured destruction’ should have the addendum, ‘and we’ll take everyone else with us’.
Overkill and megadeath
That a nuclear winter would devastate neutral countries does not seem to have featured in the considerations of the Cold War belligerents. Most of Africa and South America, and much of Asia, would not have been involved if the Cold War had turned into a nuclear war, but they would not have escaped the nuclear winter.
Perhaps what we now call ‘collateral damage’ simply didn’t feature in the minds of people used to formulating policy with terms like ‘overkill’ and ‘megadeath’. the former refers to the policy of firing more nuclear weapons than was thought to be necessary to make sure the target was wiped out and the latter means a million human deaths.
Or perhaps they regarded nuclear war as so catastrophic that they saw no point inconsidering what the world might look like after it. In 1984, British Prime Minister Margaret Thatcher said as much to the rising star of the Soviet Politburo, Mikhail Gorbachev:
I am not sure how relevant the concept of nuclear winter is when set against the destruction, incineration and death which would precede it.
The conversation took place at Chequers, the country retreat that goes with the post of prime minister, which says a lot about the impending thaw in the Cold War. The quote appears 28:30min into a podcast describing documents declassified in 2014.
MADness rejects disarmament
Reading the article, the sheer scale of devastation makes it difficult to remember that it isn’t drawn from science fiction. In Star Trek or Doctor Who, super-advanced aliens who think nothing of crossing light years of interstellar space often spend an entire episode working up such a comprehensive apocalypse, if only to be thwarted at the eleventh hour. Here is a document from the days of cassette tapes and the ZX81 describing something that our own species could have done to itself at the touch of a button. Although there are only around a third of the number of nuclear warheads now as there were in 1982, there are still more than enough for the worst-case scenario they calculated of a 10,000Mt exchange.
Sagan’s work on nuclear winter propelled him into the anti-nuclear campaigner. He was arrested twice for protesting nuclear tests in Nevada, though he reached more people with
his writing and broadcasting than his direct action. In the 1991 C-Span interview, he was scathing about American nuclear policy which, at the time, was to resist the Soviet initiative for a complete ban on testing nuclear weapons. Worse, in his opinion, was that the nuclear-armed states had all committed to nuclear disarmament under the 1968 Non-Proliferation Treaty but had made no move to meet their obligations.
The Comprehensive Test Ban Treaty was signed five years later and the number of warheads has been reduced since then, but none of the nuclear-armed states suggested a move toward full disarmament. Consequently, they are all in breach of the Non-Proliferation Treaty.In 1991, the five openly nuclear-armed states were, not coincidentally, the five permanent members of the United Nations Security Council: the USA, USSR, UK, China and France. South Africa was in the process of dismantling its warheads while Israel was thought to have a nuclear arsenal, which was confirmed when South Africa declassified the minutes of meetings in which Israeli ministers offered to sell nuclear bombs to the Apartheid government.
Today, Sagan’s concerns seem prophetic as India, Pakistan and North Korea have joined the nuclear club. The club’s old boys cannot claim any moral authority for persuading them to disarm while they themselves are in violation of the Non-Proliferation Treaty. While the new members’ arsenals are dwarfed by the old boys’, India and Pakistan could still cause a nuclear winter between them while North Korea looks as if the ability to do so is a national ambition.
The danger of complacency
Most people alive in the world today grew up with the unrealised threat of nuclear apocalypse, which makes it easy to get complacent. There is, however, no natural law that states that just because it hasn’t happened in the past, it can’t happen in the future. Worse, the brash statements coming from Washington and Moscow recently suggest that the complacency may have spread to the men whose fingers are on the trigger. So far, they are threatening no more than an expansion of their nuclear arsenals, which is an order of magnitude less serious than the Cold War when they threatened to actually use them. It is, however, a threat that implicitly includes discarding the agreement to desist from nuclear tests.When Sagan gave that interview in 1991, the Cold War had recently ended and the Soviet Union was in its final months before it fragmented into the Commonwealth of Independent States. Sagan sounds deeply frustrated at his own government’s failure to seize the opportunity to disarm while relations between the old foes were warming up:
If we were to be complacent about this issue, if we were to say…’the Cold War is over so what are we worrying about?’ Then in effect we are saying that we are confident in the sanity and sobriety of all leaders, military and civilian, of all nuclear armed nations from now to the end of time. And nobody can be sure of that…even the United States has had leaders in living memory who have shown serious instabilities.
His question remains: how confident are we of the ‘sanity and sobriety’ of the leaders of nuclear armed nations today?