On this day 70 years ago, the world and the preconditions for its health and survival changed forever. A crude bomb containing 60 kilograms of highly enriched uranium exploded 580 metres above Hiroshima. Equivalent to 15,000 tons of TNT, it was 2000 times more powerful than the British Grand Slam bomb, the largest produced until then.

The moral threshold of catastrophic attacks with indiscriminate weapons had already been crossed, with poison gas killing 90,000 and maiming or blinding one million men in the European killing fields of the first world war. This was followed by indiscriminate aerial bombing of cities during the second world war.

Nowhere was the bombing more extensive than in Japan. Between March and August 1945, 66 Japanese cities, with populations down to 30,000 inhabitants, were systematically bombed by an average of 500 bombers carrying 4000-5000 tons of bombs per city. In Tokyo on March 9-10, an estimated 120,000 civilians died in the bombing and subsequent fires.

The bombing of Hiroshima and Nagasaki

Rumours had been circulating in Hiroshima that the city was being saved for something special. It was. The burst of ionising radiation, blast, heat and subsequent firestorm that engulfed the city on August 6 killed 140,000 people by the end of 1945. Many were incinerated or dismembered instantly; others succumbed over hours, days, weeks and months from cruel combinations of traumatic injury, burns and radiation sickness.

Three days later, another B-29 carrying a bomb equivalent to 21,000 tons of TNT headed for Kokura. Because of clouds blocking visibility, its cargo was dropped over Nagasaki instead, raining similar radioactive ruin and killing 90,000 people by the end of 1945.

In both cities, ground temperatures reached about 7000° Celsius. Radioactive black rain poured down after the explosions.

AAP/Australian War Memorial

In both weapons, less than one kilogram of material was fissioned. The physics of the Hiroshima bomb were so simple and predictable that the bomb was not tested prior to use. The Nagasaki plutonium bomb required a more sophisticated design. A prototype was exploded at Alamogordo in New Mexico on July 16, 1945, detonated by Australian nuclear physicist Ernest Titterton.

The survivors of the two bombings bore the legacy of terrible injuries and scars on top of the cataclysmic trauma of what they witnessed. They also faced discrimination and ostracism, reduced opportunities for employment and marriage, and increased risks of cancer and chronic disease, which stalk them, even 70 years later, for the rest of their days.

Over the past 30 years I have had the privilege of visiting Hiroshima and Nagasaki on a number of occasions. What never ceases to amaze me is the extraordinary compassion, wisdom and humbling humanity of hibakusha. Never have I heard even the slightest hint of an understandable desire for revenge or retribution.

An unfulfilled quest

The constant yearning of hibakusha is that no-one else should ever suffer as they have suffered: nuclear weapons must be removed from the face of the earth.

In the newly established United Nations, there was the same understanding. The first resolution passed at the first meeting of the UN General Assembly in London in January 1946 established a commission to draw up a plan “for the elimination of national armaments of atomic weapons”.

Today, there is ample cause for existential despair and a poor prognosis for human custodianship of the biosphere. No nuclear disarmament negotiations are in train. Even reduced from their Cold War peak, massively bloated nuclear arsenals of 15,650 weapons jeopardise not only the living but those yet to be born.

Were one Hiroshima bomb to be detonated every two hours from the end of 1945, the global arsenal would not yet be consumed. All the nuclear-armed states continue to invest massively in development and modernisation of their arsenals. In the Conference on Disarmament, it has not been possible to agree even on an agenda for 19 years.

The five-yearly review conference of the nuclear Non-Proliferation Treaty, the principal treaty regulating nuclear weapons and legally binding nuclear-armed states to disarm, recently ended in failure. Britain, Canada and the US (acting for Israel, not even a party to the treaty), refused to accept a March 2016 deadline for a conference, promised for 20 years, to discuss a zone free of weapons of mass destruction in the Middle East.

Meanwhile, conflict in Ukraine and Crimea has re-inflamed Cold War risks of armed confrontation and nuclear war between NATO and Russia.

However, there are grounds to be hopeful about decisive progress on a circuit-breaker. The first ever intergovernmental conferences on the humanitarian impacts of nuclear weapons have been held – three in the past two years. These have led to 113 nations signing a humanitarian pledge committing them to work to fill the legal gap for the prohibition and elimination of nuclear weapons.

In a welcome development, the recent ALP national conference adopted a policy that recognises that eliminating nuclear weapons is a humanitarian imperative. The policy commits Labor to support negotiation of a global treaty banning nuclear weapons.

Other treaties show the way

States without nuclear weapons cannot eliminate them. But the dictates of common humanity, democracy, common interest and common sense, based on all people everywhere being vulnerable to the catastrophic impacts of nuclear weapons, can lead to disarmament.

As happened with landmines and cluster munitions, like biological and chemical weapons before them, unacceptable weapons can be prohibited as a necessary condition for their elimination. In the face of recalcitrant nuclear-armed states claiming a unique right to cling determinedly to their weapons of terror, concluding a ban treaty is the most practical next step the rest of the world can take.

In 1969, President Richard Nixon surprised many when he ordered an end to the US biological weapons program. The US Defence Department, which had previously declared that biological weapons lacked military usefulness, supported this.

As the then-UN High Representative for Disarmament Affairs, Angela Kane, said last year:

How many states today boast that they are “biological-weapon states” or “chemical-weapon states”? Who is arguing now that bubonic plague or polio are legitimate to use as weapons under any circumstance, whether in an attack or in retaliation? Who speaks of a bioweapon umbrella?

Yet all these things and more are claimed regarding nuclear weapons, far more destructive and indiscriminate than these other weapons.

In appealing to the 1982 UN Second Special Session on Disarmament, Hiroshima Mayor Takeshi Araki said:

Hiroshima is not merely a witness of history. Hiroshima is an endless warning for the future of humankind. If Hiroshima is ever forgotten, it is evident that the mistake will be repeated and bring human history to an end.

Nagasaki Mayor Hitoshi Motoshima added:

Nagasaki has to be forever the last city in the world bombed by nuclear weapons!

On the 70th anniversary of the bombings, banning nuclear weapons is long overdue. The remaining survivors should see negotiations on a ban treaty underway by the time a new year dawns.