Yet the potential for nuclear war remains as great as ever.

Fears that the unthinkable might happen were raised most clearly last year when President Vladimir Putin implied that Russia would consider using 'all forces and means' necessary in its fight against Ukraine.

It reminded us of the Cuban missile crisis 60 years earlier, once again bringing to the fore the prospect that nuclear war was in fact quite thinkable.

Thankfully, no nuclear weapons have been used in this war, but we cannot be complacent. Deterrence cannot be relied on forever. If Russia (or the United States) were to use even one small "tactical" nuclear weapon, a greater conflagration could easily follow.

It is not only Putin who has threatened to use nuclear weapons; nor is it the case that nuclear dangers vanished after the Cuban crisis or even after the end of the Cold War.

The leaders of every one of the nine states which possess these weapons of mass destruction - Russia, the US, France, China, Britain, India, Pakistan, Israel and North Korea - regularly signal that they would indeed use these weapons.

Their nuclear doctrines, the ongoing modernisation of their nuclear arsenals, their war-fighting practices and nuclear targeting all threaten the use of weapons which have the potential to kill millions and devastate the planet.

The end of the Cold War did nothing to reduce these dangers. While there was a period when goodwill between the major powers prevailed, and the US and Russia embarked on a program of reduction via the Strategic Arms Reduction Treaties, in truth a window of opportunity was lost when the nuclear-armed states refused to move seriously to eliminate their nuclear arsenals completely.

At the time, Australia was at the forefront of calls for the total elimination of nuclear weapons; the Labor government's Canberra Commission in 1996 put forward a sober and considered assessment of the utility of nuclear weapons.

Nineteen commissioners from around the world, including several military leaders from the US, Britain and elsewhere, concluded that nuclear arsenals had very little military utility, that their existence continued to threaten the world - via deliberate or accidental use - and that as long as any one state possessed nuclear weapons, other states would want them too.

As predicted, three more states have acquired these WMDs since the Cold War ended.

The Canberra Commission set out a comprehensive program to encourage the phased, balanced, mutual, and verified elimination of nuclear weapons. It did not call for unilateral disarmament, nor did it insist that this should happen overnight. But it did warn that dangers would increase if the world did not act to eliminate these most destructive of all weapons.

Several other organisations and think tanks around the world added to the Canberra Commission's message in subsequent decades and the nuclear states made clear promises to disarm. But they have stalled in the process of disarmament and are, instead, making their existing arsenals even more destructive than they were before.

Thoroughly fed-up with this intransigence, more than 120 states at the United Nations in 2017 voted to adopt a treaty outlawing nuclear weapons. The TPNW entered into force two years ago, and now has 92 state signatures.

Formed in Melbourne, the International Campaign for the Abolition of Nuclear weapons (ICAN) was awarded the Nobel peace prize for its work in raising awareness of nuclear dangers and its contribution towards the new treaty. This was the first and only time that an Australian-born group has been awarded the Nobel peace prize.

ICAN's work was premised on the history of banning other weapons considered to be inhumane, unjust, and uncivilised. Landmines have been banned and are hardly used at all today, a far cry from a few decades ago. Chemical and biological weapons have been banned, and any state that attempts to use them is immediately stigmatised and reprimanded.

In the same way, the TPNW is designed to stigmatise, delegitimise, and in time lead to the elimination of nuclear weapons. ICAN, the 92 governments which have signed, and people around the world who support nuclear disarmament understand that a legal instrument banning nuclear weapons is a necessary step in the move to a nuclear weapons-free world.

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It might surprise readers to know that several prominent politicians and military leaders also support this goal; Henry Kissinger and William Perry from the US are notable advocates of disarmament; so too were Ronald Reagan and Mikhail Gorbachev. Here in Australia, Labor promised at its 2018 and 2021 National Conferences that it will sign the TPNW when in government.

More than 100 federal parliamentarians have called on Canberra to fulfil this promise, as have hundreds more from around Australia, including in local government.

The call to eliminate nuclear weapons also finds strong support at the grassroots level in Australia; doctors and other health practitioners, environmental groups, trade unions, faith-based leaders, lawyers and others are calling on the government to sign the TPNW.

This is because banning and abolishing nuclear weapons is seen as a public health and humanitarian imperative. Our planet is worth preserving and human life should be valued. The Australian Red Cross as well as prominent Rotarians around the world are calling for the elimination of nuclear weapons, in the same way that they are working to eliminate polio and malaria.

On this second anniversary of the Treaty on the Prohibition of Nuclear Weapons' entry into force, Australia must again take up the message of the Canberra Commissioners. Indeed, while Australia's high-risk nuclear propelled submarine proposal clearly creates global proliferation concerns, by signing the TPNW Australia can demonstrate its non-proliferation commitments.

A nuclear-free world requires visionary and bold leadership. It is a global public good. Signing the TPNW, and playing an active role internationally for balanced, phased and verified disarmament will be an excellent start.