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Re-examining the decision to bomb Hiroshima

Hiroshima Peace Memorial

Not forgotten: The Hiroshima Peace Memorial is dedicated to the 140,000 people killed in the city. (Courtesty: iStockphoto/Colin13362)

By Hamish Johnston

Today marks the 70th anniversary of the bombing of Hiroshima – the first time that a nuclear weapon was used in war. Many argue that the bombing of Hiroshima, and three days later Nagasaki, was a necessary evil that saved hundreds of thousands of lives by ending the war and avoiding an allied invasion of Japan.

Over on The Nuclear Secrecy Blog, the science historian Alex Wellerstein asks “Were there alternatives to the atomic bombings?”. Wellerstein argues that the choice facing the US in 1945 was not as simple as whether to bomb or to invade. He points out that some physicists working on the Manhattan Project – which built the bombs – argued for a “technical demonstration” of the weapons.

In June 1945 the Nobel laureate James Franck and some colleagues wrote a report that argued that the bomb should first be demonstrated to the world by detonating it over a barren island. Wellerstein surmised that “If the Japanese still refused to surrender, then the further use of the weapon, and its further responsibility, could be considered by an informed world community”. Another idea being circulated at the time was a detonation high over Tokyo Bay that would be visible from the Imperial Palace but would result in far fewer casualties than at Hiroshima, where about 140,000 people were killed.

On the other hand, Wellerstein points out that Robert Oppenheimer and three Nobel laureates wrote a report that concluded “we can propose no technical demonstration likely to bring an end to the war; we see no acceptable alternative to direct military use”. This report was written for a US government committee, which decided to use the weapon against a “dual target” of military and civilian use.

This morning in Hiroshima there was a ceremony to remember those who died in the attack and its aftermath. Addressing a crowd of 40,000, Hiroshima’s mayor Kazumi Matsui pointed out that “Our world still bristles with more than 15,000 nuclear weapons”. Indeed, at least nine countries have nuclear weapons and Matsui added “We now know about the many incidents and accidents that have taken us to the brink of nuclear war or nuclear explosions. Today, we worry as well about nuclear terrorism.”

A question that has been asked in the run-up to the anniversary is whether we have avoided nuclear war over the past 70 years because we are acutely aware of the horrors of Hiroshima and Nagasaki or because we have simply been lucky? Furthermore, if we allow Hiroshima and Nagasaki to be forgotten – or our luck runs out – will we follow a path to self-destruction?

As Matsui pointed out, there are thousands of weapons worldwide today and they are much more powerful than the bomb that destroyed Hiroshima. This is illustrated rather chillingly in this infographic by Maximilian Bode, which shows that self-destruction is still a possibility.

The idea of advanced civilizations destroying themselves is relevant beyond our world. One resolution of the Fermi paradox – which asks if advanced alien civilizations exist, then why haven’t we noticed them already? – is that once a civilization has the capacity to destroy itself, it is very likely to do so.

In the preprint “Observational signatures of self-destructive civilisations”, the UK-based astronomers Adam Stevens, Duncan Forgan and Jack O’Malley-James “consider a variety of scenarios in which humans could extinguish their own technological civilization”. They then try to work out whether these cataclysms would produce signature signals that could be detected over interstellar distances. Nuclear annihilation is one of the scenarios discussed. Let’s hope that the lessons learned from Hiroshima and Nagasaki ensure that the Earth will not be sending out such signals in the future.

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  1. One of the reasons that USA felt obliged to drop the atomic bombs on Japan was the way Russia was behaving. To ensure that a strong message is sent to USSR about the superior military power that USA now possessed, demonstration of the bomb was necessary. Klaus Fuchs had given away the secrets of the bomb to USSR and they tested their atomic bomb soon after the war. This encouraged the work on the fusion bomb be given high priority starting an arms race…

    • Hamish Johnston

      Ending the war before the USSR turned its sights on East Asia was probably another consideration. As Wellerstein points out, the Americans had realized by July 1945 that a Russian invasion of Japan would not be in their long-term interests.

  2. M. Asghar

    The nuclear bomb has been right from the beginnning a geopolitcal tool of power in the hands of USA, and when other nations developed it, it became and remains an effective mutual-annihilation deterrent. Due to this existential reason, in the present situation, the nuclear disarmament cannot go beyond the talking stage.

  3. Terry Jones

    I don’t have the details in front of me but as I understand, the US firebombed Tokyo a few days before the atomic bombs and killed around 150,000 which is more deaths than both nuclear bombs combined. Is it any worse getting burned to death than a nuclear explosion or the other way around? And don’t forget Pearl Harbor!

    • Lee Krystek

      I believe that more people died in direct effects of the bombing at Tokyo than Hiroshima and Nagasaki, but when you take the longer term death told from the radiological effects into account, the atomic bombing have a high toll. Still, they are somewhat in the same range which I think makes your point valid.

  4. Ed

    The debate contnues as to the merit of using the A-bomb on Japan and perhaps it bears greater analysis and debate as to whether or not one type of weapon is moral than another, the result is the same-death. Millions more people were killed in the fire raids on Japan with conventional bombs, does the fact that one bomb vs many bombs killed so many people? Does the fact that this was total war to be fought to the dead make any difference? Would the dropping of the A-bomb on he Germans have made the debate any different? If the US had been attacked with an A-bomb, would that have made our counter-use of the same weapon any more morale?

  5. Ed


    Here is another factor to consider: if the US had never dropped two atomic devices, others in the world at some later date may have been embolded by the use of the weapon and it potential uses. Since the world witnessed two major cities destroyed and the death toll at 100,000+ in each city, deterrnance was shown through the illustration of the destructiveness of an A-bomb on real targets and people and not merely the sterile blasts that we saw later in the Bikini Atoll.

  6. Robert Matthews

    As historian Richard Rhodes makes clear in The Making of the Atomic Bomb, the question of whether or not a demonstration of its destructive power would have persuaded the Japanese command to surrender was definitively answered – twice. The bombing of Hiroshima,which had been expected to prompt surrender – did not. Incredibly, even after the Nagasaki strike, the Japanese High Command were determined to continue. It took the personal intervention of Emperor Hirohito himself to bring about surrender, and thus avert the use of a third atomic bomb, which was being prepared by the Allies.

  7. Andrea Di Vita

    “Had the atomic bomb turned out to be something as cheap and easily manufactured as a bicycle or an alarm clock, it might well have plunged us back into barbarism, but it might, on the other hand, have meant the end of national sovereignty and of the highly-centralised police state. If, as seems to be the case, it is a rare and costly object as difficult to produce as a battleship, it is likelier to put an end to large-scale wars at the cost of prolonging indefinitely a ‘peace that is no peace’.” George Orwell, ‘You And The Atomic Bomb’, 1945

  8. SenseiBear

    Should it ever happen again, whether the device be nuclear or otherwise, that will be the moment when all of humanity must know that they collectively failed. The end never justifies the means, but wisdom and enlightenment can make amends for a great many things – even this.

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