9 August 2017 How worried should we be about a nuclear war with North Korea? History is littered with near misses, but the latest tensions between the US and North Korea offer their own special risks of armageddon. Getty Sign UpGet the New Statesman's Morning Call email. Sign-up On the anniversary of the US nuclear bomb attack on Nagasaki in 1945, rhetoric from both Kim Jong-Un and Donald Trump has one again raised the spectre of nuclear war in the Pacific. Back in 1953 as the Korean War drew to an end, the US President Dwight Eisenhower drew up detailed plans to use nuclear weapons – if deemed necessary – reversing the previous US administration’s determination not to use them. The talk of attacking Guam – which is home to some 160,000 civilians, including the indigenous Chamorros, and is one of the US military’s most strategic bases with submarines, fighter jets, bombers, missiles (including the terminal high altitude area defense (THAAD) battery), ships and ordnance along with thousands of troops including US Marines - has escalated the already dangerous situation. Nuclear weapons have not been used in conflict since the end of World War II – although many have been exploded as part of weapons development and testing programmes. They are qualitatively different from other weapons. Because the energy in the atomic nucleus is much larger than the energy in chemical bonds, nuclear explosions have far greater impacts than conventional explosives. This is why one nuclear bomb could destroy a city such as Hiroshima or Nagasaki in 1945. Since then nuclear weapons have become more sophisticated and have been designed with even greater explosive power. One warhead could obliterate hundreds of thousands of people in a single explosion. Nuclear explosions not only create enormous blasts and fires but also release highly damaging radiation and long-term radioactive debris (known as fall-out). There is no effective capacity at the international level to deliver immediate humanitarian assistance to survivors if nuclear weapons were ever to be used, humanitarian workers would have to wait for radiation levels to be safe or they will just add themselves to the sick and dying. The effects of nuclear weapons can last for decades and, depending on how many are used and where, they have the potential to negatively impact the global climate causing long-term crop growth problems and potential starvation. Because of their huge and clumsy impact – there is no such thing as a small mistake with nuclear weapons –international efforts to prevent countries from acquiring nuclear weapons have been in force for decades. In 2020, the nuclear Non Proliferation Treaty will have been in force for 50 years and, a few weeks ago at the UN, 122 countries negotiated and adopted the Treaty on the Prohibition of Nuclear Weapons. The International Atomic Energy Agency (the IAEA) is charged with safeguarding civil nuclear energy facilities to ensure that countries without nuclear weapons cannot acquire the special materials such as uranium and plutonium needed for nuclear weapons. Despite all these efforts and promises made to eliminate, thousands of nuclear weapons remain in the hands of a few countries: China, France, India, Pakistan, Russia, UK have them, though Russia and the US possess the vast majority. It is widely believed that Israel has nuclear weapons but this has never been confirmed. Now it is likely that North Korea is at least very close to having them, or already does. There have been several occasions in which nuclear weapons were very nearly used deliberately. Most of those near misses were in the cold war at times of crisis and the stories of how they came about are sobering. The Cuban missile crisis is perhaps best known as the nearest the world came to global nuclear war – and things were far worse then than most people realise – but there have been several other close shaves. The most chilling has recently been portrayed in the film ‘The man who saved the world’ which tells the true story of Stanislav Petrov, a USSR military officer who was commanding an early warning station in 1983 – a very unstable year in US-USSR relations – when his computer screens showed a stream of incoming US nuclear ballistic missiles. His decision to wait-and-see rather than act as he had been instructed saved the lives of millions. Other too-close-for-comfort examples include a Russian double agent and a code that would have triggered a nuclear response had it not been for cool heads and mature thinking, and the case of Able Archer – a live-fire NATO exercise which was believed by many in East Germany and Russia to be a pretext for a real attack. Again, cool heads and the work of back-channels saved the day. The progress that Iran made towards a nuclear weapons capability led to the 2015 Joint Comprehensive Plan of Action (JCPOA) aimed at ensuring that Iran cannot develop a fully-fledged nuclear weapons programme, but attempts since the early 1990s to do the same with North Korea have failed. The speed of developments within North Korea’s ballistic missile programme and their five nuclear warhead tests have led the US Defence Intelligence Agency and the Japanese government to fear that North Korea may already have crossed the threshold and possess deliverable nuclear ballistic missiles. If North Korea were to attack any US base in the Pacific with conventionally armed missiles, the US would have moved many key strategic assets away from the target and would aim to intercept many of those missiles and immediately strike back. There would be no need for the US to use nuclear weapons; the US conventional armoury is well known and would deliver a "fire and fury" attack as President Trump telegraphed. Such a response would be seen as proportionate and would likely be supported by most countries in the Pacific and around the world. At that point, North Korea could decide to come to the negotiating table, or it could decide to escalate further and could begin a land, sea and air invasion of South Korea or indeed attempt to detonate a nuclear warhead either by missile or by other means such as ship. It is also possible that complete chaos could erupt in North Korea with a challenge to its leadership. If North Korea has the capability to use nuclear weapons and aimed at Guam or any other base, the US would first attempt to intercept the incoming ballistic missile(s) with missile defences. However, this type of interception is notoriously difficult and cannot be relied on. If a North Korean nuclear attack were successful, depending where and how it exploded, thousands to hundreds of thousands of people could be killed. The US response could be measured. There would be no need to use nuclear weapons and such restraint would likely be rewarded by support from other regional powers including China. The use of nuclear weapons by the United States, which might be viewed perhaps by US allies as a proportionate response would likely lose the support of Russia and China and other countries. The US would face internal opposition, including from some of its own population – although there are many who would support nuclear use in retaliation. The number of potent scenarios that could unfurl are numerous and each contains enormous risks and potential for miscalculation and catastrophe. Partly because of their isolation and fears, North Korea believes that their nuclear weapons will deter attack from the United States. This is undoubtedly a miscalculation on their part. Despite recent agreement in the UN Security Council, their nuclear weapons developments are acting more as a lightening rod for an attack. Countries that believe in nuclear weapons as a deterrent – such as the UK and France – have long-speculated as to what would happen if nuclear deterrence strategies fail. We may be about to find out in North East Asia. Patricia Lewis is research director for International Security at The Royal Institute of International Affairs at Chatham House. › Gina Miller threatened with acid attacks “for months” Subscribe For more great writing from our award-winning journalists subscribe for just £1 per month!