In the 1964 Hollywood movie ‘Dr. Strangelove’, the US president called the Russian Premier to inform him of a hydrogen bomb attack by a US base commander on USSR: “Dmitri… Just a little funny. And uh, he went and did a silly thing.” Today, there are at least nine countries with a total of more than 15,000 nuclear warheads, and the US possesses 6,800 of them. Thus, the possibility of such a phone call has been intensified as the leaders of these countries even quarrel on the sizes of nuclear buttons on their desks.

January approaching, it will be time again to reset the ‘Doomsday Clock’. The ‘Doomsday Clock’ which has been maintained by the members of the Bulletin of the Atomic Scientists’ Science and Security Board since 1947, represents how far we are from the hypothetical global catastrophe, denoted by ‘midnight’.

The hands of the symbolic ‘Doomsday Clock’ were forwarded last January, to two minutes to deadly ‘midnight’, the smallest-ever gap to midnight equating the 65-year-old 1953 mark. There is little doubt that the nuclear tension originating from the northern part of the Korean peninsula played havoc towards that advancement of the hypothetical indicator clock.

Then, in June 2018, the world witnessed the event of the year – the Merlion Summit in a resort island of Singapore, between two leaders who preferred to call each other ‘Little Rocket Man’ and ‘Dotard’. But, have we moved towards complete denuclearisation in the Korean peninsula since then?

The South Korean leader Moon Jae-in certainly played a positive and active role in this peace process. President Moon has already met both Chairman Kim and President Trump, separately, a number of times in between. Seoul is now eagerly waiting for the first visit of a North Korean leader after the Korean War. And, understandably, this might contribute immensely towards the peace process.

Time and again we have heard that President Trump has a “very friendly view” of Kim and wants to grant his wishes if Kim denuclearises. And North Korea might seek complete guarantee of security and economic sanctions to be lifted first before they go for denuclearisation completely. Clearly, it’s a tug-of-war – who’s going to act first, if at all. It seems a tough game of trust building.

What can really happen with the present strength of nuclear weapons worldwide? Well, more than seven decades back the Hiroshima and Nagasaki bombs killed at least 129,000 people and caused traumatic and very-long-term health effects on many. However, the 15-kiloton Hiroshima bomb ‘Little Boy’ was really little, and the 21-kiloton Nagasaki bomb ‘Fat Man’ was no way fat compared to today’s arsenals. Let’s have an idea of the catastrophic capacity of a hydrogen bomb in today’s world. An atomic bomb generates energy through the process of nuclear fission where the nucleus of an atom splits, while the hydrogen bomb’s fusion produces explosive energy where atomic nuclei come together.

With lots of available information about the cataclysmic power of such weapons, it is now possible to ‘simulate’ the nature and quantum of possible destruction of the much more powerful H-bomb on a computer. ‘Nukemap’ is perhaps the best-known tool in this context; it is an interactive map using Google Maps Application programming interface and unclassified nuclear weapons effects data. This was created by a historian of science at the Stevens Institute of Technology named Alex Wellerstein. There are other simulators to gauge and increase public awareness about the dangers of nuclear weapons.

One such recent blast simulator was created by a Wisconsin-based educational non-profit called the Outrider Foundation. If a 100 kiloton H-bomb is dropped over Sydney’s Centrepoint tower, that would wipe out the city and only those west of Homebush would have a minimum chance of survival.

The largest nuclear weapon ever tested is the 50 megaton ‘Tsar Bomba’ in 1961 on an isolated island in Russia, which released roughly the energy of 3,333 Hiroshima bombs combined. If it hits London, it would cause 5,778,170 estimated fatalities and 3,421,250 estimated injuries demolishing heavily built concrete buildings within a 8.91 km-radius with a fatality rate of almost 100 per cent. Third-degree burns would occur within a radius of 60km.

Earlier, before the Trump-Kim summit, it was reported that Kim Jong-un was considering the test of a H-bomb in the Pacific Ocean as a response to Trump’s threat “to totally destroy North Korea”. A 400-page long US military report of 1996 by Bernard Le Mehaute and Shen Wang of the Rosenstiel School of Marine & Atmospheric Science has some clue that after detonation an expected shockwave radiating outward and carrying upwards of 140 kilotons of energy resulting in plasma unleashes into the water, sending massive amounts of water vapour and miscellaneous debris into the air.

Understandably, Moon Jae-in has reason to be anxious – if North Korea strikes Seoul with its latest 150 kilotons nuclear weapon, which it is capable of, a fireball of a radius of around 1.09 kilometres would vaporise all buildings inside and would instantly kill 215,270 people. This is according to the ‘Nukemap’ simulation.

A further 560,610 severely injured in radiation exposure are likely to die within several months or years. The core of a nuclear bomb can reach a whopping 66 million degrees Celsius, compared to 300,000 degrees Celcius of the Hiroshima explosion. Radiation with a 50-90 per cent mortality rate within 11.8 square kilometres would cause death between several hours and several weeks.

Neighbourhoods like Susong-Dong, Chungmuro, Migeun- Dong and Sinunno would be completely wiped out. That’s certainly not all – a thermal radiation causing third-degree burns up to 68.4 square kilometres from impact point would effectively wipe out Seoul and its 51.44 million people. Well, the neighouring countries, even North Korea, would not be able to escape. Millions would eventually die in North Korea, Japan, Taiwan and huge swathes of China.

And, we know very well that the “silly thing” might trigger the third world war with the possibility of many such bombings in different places on the globe, and thus a head of the state might not find it really “funny” to call his/her counterpart.

On the one hand, it is very difficult to monitor the North Korean nuclear programme. Also, there is a serious apprehension that Kim Jong-un might not give up the programme so easily. In early November, North Korea indicated that the country may consider returning to its previous “byungjin policy” of parallel development of the economy and nuclear weapons, originally announced by Kim in 2013, if the United States sticks to its current course.

While playing with the hypothetical ‘Doomsday Clock’ next time, the time gap to ‘midnight’ might widen a bit in January 2019 – courtesy the much-hyped Summit when the ‘Dotard’ shook hand with the ‘Little Rocket Man’ in Singapore. But, in order to make the planet a safer place, something more concrete than bubbles might be needed. Can we really hope for something more promising in the coming second Trump-Kim summit in early 2019?

The writer is Professor of Statistics, Indian Statistical Institute, Kolkata.