The Trump administration’s stated intention to develop a new generation of American nuclear weapons was “highly inflammatory”, said Associate Professor Amy Maguire, a senior lecturer in international law at the university.

“It is not yet clear whether it will be followed through, or whether the announcement of this intention was a strategic move to put pressure on Russia.”

She also considered the intention to be “disingenuous”.

“The US continually enhances its nuclear capability – it is not as though the US has had warehouses full of old bombs gathering dust for decades and now they are starting afresh,” she said.

Nevertheless, she said the global stockpile of nuclear weapons had been reduced significantly to 14,700. The Cold War arms race led to a stockpile of an estimated 70,000 weapons.

“However, arms control agreements that have been key to achieving this reduction are increasingly under pressure,” she said.

She said the US and Russia had repeatedly accused each other of violating various arms control treaties.

“In October this year, President Trump announced that the US will withdraw from the Treaty on the Elimination of Intermediate-Range and Shorter-Range Missiles [commonly known as the INF treaty].” 

The US said Russia had violated the treaty by developing a new cruise missile. The US was also concerned about having no response to Chinese missiles. China is not part of the treaty.

“If Russia’s doing it and if China’s doing it and we’re adhering to the agreement, that’s unacceptable,” Mr Trump said in October.

Former Soviet president Mikhail Gorbachev cited withdrawal from the INF treaty and the Iran nuclear deal as evidence that the US had declared a new nuclear arms race. 

“This is of particular concern given the massive and growing rate of military spending globally,” Associate Professor Maguire said. 

She said Australia’s refusal to endorse the Treaty on the Prohibition of Nuclear Weapons “indicates how we see ourselves in relation to the world’s nuclear powers, none of which has endorsed the prohibition treaty”.

“Australia is one of 30 states that are regarded as nuclear weapons-endorsing states. This bloc of states rely on what they regard as the nuclear protection of allies.

“Australia’s government argues that a ‘building blocks’ approach to disarmament is preferable to the prohibition required by the treaty.”

But by refusing to participate in the drafting of the prohibition treaty, she said Australia “missed an opportunity to contribute positively to nuclear disarmament”.

“The treaty is far from perfect, not least because it does not include the nine nuclear-armed states. Had countries like Australia participated in the drafting more productively, a different agreement could perhaps have been reached,” she said.

“Such an agreement might, for example, have allowed for a phase in which weapons stockpiles were reduced prior to full elimination and prohibition.”

She said there were several reasons why a nuclear bomb hadn’t been used since World War II.

“One may be that nuclear power has spread over time – only the United States had nuclear weapons during WWII but there are now nine nuclear powers.

“During the Cold War, the US and Russia amassed such massive stockpiles of nuclear weapons that the concept of mutually-assured destruction has been said to have operated as a deterrent to the use of nuclear bombs.”

The weapons themselves have also become considerably more destructive as the science has been refined.

The fact that nuclear weapons had not been used in warfare since 1945 “means that it is difficult for people today to conceive of nuclear warfare as a real threat in the world”.

“I wouldn’t describe this as complacency, as human beings have real difficulty dealing with indeterminate risks,” she said.

“It’s important to recognise that, while nuclear warfare may seem a very remote possibility for most people in Australia, it is perceived as a much more real risk in other parts of the world. The Japanese and South Koreans, for example, continue to drill for the risk of nuclear attack.

“The nuclear weaponry now held by the world’s nuclear powers is sufficient to destroy the world several times over.”

The United States government began funding an atomic-bomb development program in 1939 over fears that Nazi scientists were working on a weapon using nuclear technology. 

A classified research and development effort, code-named the Manhattan Project, produced the first nuclear weapon in history. On July 16, 1945, the first atomic bomb was successfully detonated in a test in the New Mexico desert. It created a gigantic mushroom cloud that marked the beginning of the Atomic Age. 

The US then dropped an atomic bomb on Hiroshima in Japan on August 6, 1945, during WWII. It was the first time in history that an atomic bomb had been deployed in war. The explosion immediately killed an estimated 80,000 people. Thousands more died from radiation poisoning.

The Japanese did not surrender, so the US dropped a second atomic bomb three days later on Nagasaki, killing an estimated 40,000 people. Total deaths by the end of 1945 may have reached about 80,000.

Japan’s Emperor Hirohito subsequently announced his country’s surrender, citing the “new and most cruel bomb” and the threat of “the total extinction of human civilisation”.

The uranium-based bomb dropped on Hiroshima was nicknamed Little Boy. The Nagasaki bomb, nicknamed Fat Man, was made with plutonium. 

The bombs ended the war, then sparked a nuclear arms race that brought the world to the brink of destruction. 

Associate Professor Maguire visited the Hiroshima Peace Memorial Museum in June last year.

“It was an experience I will never forget. It was a wet day, which added to the sombre feeling of the place, but my sense of its tragic history was also tempered by the vital nature of the site and how it is used by the Japanese people,” she said.

“The entire park and the memorial museum were filled with Japanese schoolchildren of all ages. They learn about the bombings and nuclear energy and weapons, remember those who died and suffered and contribute to the memorial by bringing strings of paper cranes.”

She said the incredible scale of destruction inflicted by nuclear weapons was “still so obvious at the Peace Park over 70 years on”.

“The Genbaku Dome was the only building left standing near the hypocentre and it remains as the most recognisable feature of the Peace Park, surrounded now by a rebuilt modern Hiroshima.

“The memorial museum presents testimonies of survivors and the stories of the dead. It reveals the insidious nature of nuclear warfare and its human impacts, from the initial and catastrophic destruction of lives and infrastructure, to the longer-lasting impacts such as radiation sickness and cancers.”

Some of the museum’s artefacts were overwhelming.

“I cried throughout my visit to the museum,” she said.

“The central message of the museum is that nuclear weapons are so inhumane as to justify their global prohibition. The museum maintains clocks that tally the number of days since the bombings of Hiroshima and Nagasaki, and since the most recent nuclear weapons test.”