When the first British nuclear test explosion in South Australia on 15 October, 1953 shook the ground, an oily radioactive black mist spread fear and acute radiation sickness among the people living at Wallatinna, Yami Lester was just a young boy.

Yami was blinded, and many in his community died. In June his daughter Karina Lester told the United Nations conference that was negotiating a new treaty to ban nuclear weapons: “We are constantly reminded of what has been taken away from us as a family and the suffering we have been through.”

On behalf of indigenous organisations in 10 countries, she described how: “Our land, our sea, our communities, and our physical bodies carry this legacy with us now, and for unknown generations to come … Our suffering cannot be undone.  Our lands can never be restored.  Some of our customs will never be revived and will forever remain disrupted.”

Yet this terrible legacy is just a small taste of the radioactive incineration and global famine that a nuclear war would unleash.

Like Sue Coleman-Haseldine, displaced from her birthplace by the nuclear tests, who spoke to the first negotiating session in March, Karina called the treaty “a historic opportunity towards ensuring that there are no new victims of nuclear weapons”.

Nuclear weapons, the most destructive, indiscriminate and inhumane of all; the last weapon of mass destruction to be outlawed by an international treaty, have always been immoral and unacceptable. They are the only weapon that poses an acute existential threat to all humanity and everything that we love and depend on.

Forget the notion of Mutually Assured Destruction (MAD) and the myth somehow nuclear weapons would never be used again by rational leaders. The science is clear: even a tiny fraction of the global nuclear arsenal would loft millions of tons of smoke from burning cities into the upper atmosphere. This would darken, cool and dry the earth, decimate food production, and threaten billions of people with starvation. The reality of use of nuclear weapons is Self Assured Destruction. Nuclear weapons are effectively global suicide bombs.

The frightening brinkmanship and extreme threats traded between Donald Trump and Kim Jong-un are just the latest by a succession of leaders making explicit threats to use nuclear weapons, including Theresa May, Vladimir Putin, and leaders in India and Pakistan. The risk of lurching into a nuclear war that nobody wants are as high as they have ever been. There should be no buttons that enable any human hands to destroy our world. As Ban Ki-moon said, there are no right hands for the wrong weapons.

The Treaty on the Prohibition of Nuclear Weapons, adopted by 122 to 1 on 7 July 2017, for the first time makes them illegal. It codifies in law that nuclear weapons must never be used again and the only way to ensure this is to eliminate them.

Throughout the development of the treaty, Australia has been missing in action, languishing on the wrong side of history. Australia has opposed the treaty because of our delusional claim to rely on US nuclear weapons to keep us safe and prosperous. Nothing could be further from the truth. While Australia has joined the treaties that ban biological and chemical weapons, landmines and cluster munitions; for the first time, we have boycotted multilateral disarmament negotiations, intended to ban the worst weapons of all.

Yet New Zealand is among a number of countries that have shown us that a military alliance with the US that excludes nuclear weapons is entirely feasible.

The treaty banning nuclear weapons opened for signature at the UN in New York on 20 September. Within an hour, 42 states had signed; more than expected. It was 50 by the end of the day. Another three signed later in the week. More will come.  This treaty provides a clear path to the elimination of nuclear weapons. There is no other plan. The treaty provides our best hope. All states, including Australia, the US and North Korea, should take it.

Associate Professor Tilman Ruff AM is co-president of International Physicians for the Prevention of Nuclear War and founding chair of the International Campaign to Abolish Nuclear Weapons (ICAN).