In late February, the United States and Russia found themselves without an agreement about the disposition of their major strategic nuclear weapons for the first time in more than 20 years.

The previous international agreement was called New START and applied to all strategic nuclear weapons on both sides. But with advances in time and technology and developments in these destructive technologies, the world will become increasingly unpredictable. If a new international agreement can be negotiated, in my view it may be the last such understanding in world history.

The central challenge to what are highly intricate technical and political negotiations is that from the US point of view they must soon include China as a nuclear superpower. In previous talks, China refused to discuss any of the technical issues involved because it had fewer land and sea-based intercontinental nuclear weapons than either the US or Russia. But by the early 2030s, it will have nuclear forces approaching those of each of its competitors. This will mean that, by about that time, Russian and Chinese nuclear weapons together will greatly outnumber the US’s. That would be an outcome unacceptable to Washington.

After more than 30 years of highly secret and tightly held technological developments, according to some nuclear experts we may be heading towards new diplomatic confrontations between China and the US about nuclear arms control. The best outcome could be another arms control agreement under which each of the three parties would hold dangerously high numbers of missiles. At the moment, however, China is standing by its view that, having so few long-range nuclear missiles compared with the US and Russia, it should enter into no arms control agreements.

Russia has 5,459 deployed and stored strategic nuclear weapons. The US has a comparable declared total of 5,177. The rest of the world scarcely rates. China has only 600 warheads but, according to the Pentagon, will have 3,000 warheads by 2030, due to its massive new program for intercontinental ballistic missiles. It will therefore be approaching US warhead numbers. To reach this predicted level China must prepare highly advanced engineering skills for designing new nuclear weapons and their delivery systems. It must also divert production resources to building expensive land-based intercontinental ballistic missiles, submarine-launched ballistic missiles, the huge vessels that carry them, and costly intercontinental bombers.

Other countries’ nuclear weapons holdings do not rank in scale with those of the big three of the US, Russia and soon China. According to reliable published sources, France has 290 nuclear weapons, Britain 225, India 180, Pakistan 170, Israel 90 and North Korea 50.

And then there is the question of the possibility of a dramatic new breakthrough in limited nuclear warfare capability. Using new technology, particularly warheads of significantly smaller size and power, it may be possible with nuclear weapons to solve issues between nations without escalating to general nuclear wars. Consider the possibilities of North Korean leader Kim Jong-un, urged on by Russian President Vladimir Putin with no constraints, engaging in nuclear theatre warfare. The end may only come after several cities including some in Northeast Asia are hit with North Korea’s nuclear weapons and radioactive contamination is allowed to work its way through their urban populations. Breakthrough reductions in nuclear weapon sizes could allow limited nuclear use to deal with specific problems. This is just one crucial technical consideration in exploring the pros and cons of future nuclear destructive power.

More than 80 years have passed since the atomic bombings of Hiroshima and Nagasaki sprang total surprise on Japan and the rest of the world. Since the Cold War ended, our attention has drifted away from nuclear weapons, but they again require our close attention and preoccupation.

China is still only the new kid on the big-time nuclear block. So, for the moment, its new ICBM numbers and any submarine technological breakthroughs will still be excluded from consideration in any agreed new balance. This opens the way for China to develop a highly threatening strategic nuclear superiority, at least in theory. I have reason to believe it is aiming to develop nuclear superiority over the US well in excess of 1,000 strategic nuclear warheads. That would be simply unacceptable to Washington, not least because it could result in the US facing nuclear defeat against two powerful enemies with far larger arsenals. The US’s policy for nuclear war may also need to consider lowering its threshold for nuclear use.

The following scenarios are among the most likely to lead to nuclear escalation:

—Iran, having built nuclear weapons, at war with the US and Israel;

—North Korea in a war with South Korea that also involves China, the US and Japan;

—Taiwan in a war involving China, Japan, the US and Australia;

—India in a general war with Pakistan; and

—Russia facing imminent defeat in Ukraine.

Most of these conflicts could begin over local territorial disputes that may escalate into more general armed conflict in which nuclear weapons may be employed.

A primary challenge in the complex technical and political negotiations around nuclear arms control is the necessity, from the US perspective, to recognise China as a nuclear superpower. By 2030 China will no longer have the excuse it has used in avoiding negotiations: it will be comparable with each of its competitors in nuclear weapons. For neither of them will that be acceptable.

As far as Australia is concerned, we must make it perfectly clear to other nations that we are not interested in ever acquiring nuclear weapons. In the 1960s, Australia came perilously close to making some nuclear bombs to be stationed in Jervis Bay on the New South Wales coast. But the proposal was shelved.

Australia also needs to encourage its neighbours, especially Indonesia, to refuse to acquire nuclear weapons under any conditions.

I am told by reliable official US sources that since last year China has been targeting the US-Australian Pine Gap facility with its strategic nuclear rocket forces. This shows that China is not simply increasing its nuclear inventory; it is also thinking seriously about how to fight a nuclear war, with all that means for Australia.