When the world didn’t end

“We’re going to blast them now! We will die, but we will sink them all – we will not disgrace our navy!” These are the words that Valentin Savitsky reportedly cried as he ordered his submarine’s nuclear torpedoes to be readied for immediate launch. Savitsky was the captain of B-59, one of a group of Soviet subs dispatched to the Caribbean during the Cuban missile crisis. Tensions between the Americans and Soviets were already sky-high. What happened next would take the world to the very edge of nuclear conflict.

On 27 October 1962, American vessels began dropping practice depth charges (containing very little charge) in the area that the Soviet subs were patrolling, in an attempt to force them to the surface. The Americans informed the Soviets in advance but this was not passed on to the subs’ commanders. So when a charge hit and damaged B-59, Savitsky felt he had no choice but to fire, believing war may have already broken out.

Only the intervention of his second in command, Vasili Alexandrovich Arkhipov, prevented the torpedoes being launched and war breaking out. Arkhipov persuaded his colleague to make a humiliating surface under enemy fire so that they could return home and receive new orders. While the submarine crews were publicly disgraced for having violated strict orders of secrecy, Arkhipov was permitted to continue his career in the Soviet navy and retired as a vice admiral in the 1980s.

2) Smallpox strikes again

11 September 1978

Not all of humanity’s close brushes with annihilation are the result of nuclear mishaps. Infectious diseases also possess a terrifyingly deadly power – and that became abundantly clear in the summer of 1978.

The last known natural case of smallpox was in 1977. Yet the following year, it killed again. Its victim was Janet Parker, a photographer working at the University of Birmingham Medical School, in an office above a laboratory where samples of the virus were being studied.

Scientists continue to retain stocks of smallpox. Could the virus escape a lab and cause a global pandemic? It’s hard to say but the Parker incident is not the only time that accidents have happened. (The 2007 foot and mouth outbreak is believed to have been caused by a laboratory escape.) In 2014, it was discovered that smallpox was being inappropriately stored at the US National Institutes of Health campus in Maryland, increasing the chance of infections spreading to the population.

Only one other person contracted smallpox in 1978 – Janet Parker’s mother, and she survived. In a globalised world where we no longer routinely vaccinate against smallpox, next time we may not be so lucky.

3) A Soviet sceptic saves the world

26 September 1983

Shortly after midnight on 26 September 1983, Lt Colonel Stanislav Yevgrafovich Petrov – duty officer at the Serpukhov-15 secret bunker just outside Moscow – received some alarming news from the USSR’s satellite early warning system: the Americans had launched five nuclear missiles, and they were all heading for Russia. Soviet doctrine made it absolutely clear what should happen next: an immediate nuclear counterattack.

But Petrov was sceptical. Given the size of the Soviet retaliation that would inevitably follow, surely an American first strike would consist of more than five missiles? He therefore called it a false alarm, preventing the launch and, by extension, a ruinous nuclear war.

Petrov’s instincts were correct. There were no missiles. The satellites had, it turned out, been fooled by unusual atmospheric conditions.

Following the incident, Petrov was moved to a less sensitive military position and later left the army following a nervous breakdown. It has been suggested that such false alarms were not uncommon and that this famous incident is simply the only one to receive public attention.

4) A game with no winners

November 1983

In the middle of one of the hottest periods of the Cold War, 40,000 Nato troops advanced east across Europe. They were taking part in Operation Able Archer, a huge war game that almost had catastrophic consequences.

What set Able Archer apart from its predecessors was its realism (even Margaret Thatcher played a role in the simulation). But that realism also made it dangerous. For the Soviet leadership – who had long suspected that the west was preparing a first strike disguised as a military exercise – believed this was a genuine attack, and formulated plans to strike back.

Nato leaders initially believed that these mobilisations were part of the Soviets’ own war games. It was not until they received reports by a KGB double agent in London, Oleg Gordievsky, that Nato leaders realised the seriousness of the USSR’s response and the potential for retaliation. One historian of the CIA concluded that “only Gordievsky’s timely warnings to the west kept things from getting out of hand”.

5) Fear and loathing in Kashmir

May and June 1999

Pakistan has been at loggerheads with India for much of its 70-year history. But as the 20th century drew to a close, a new, potentially lethal dimension was added to the combustible relationship: nuclear weapons. India tested its first bomb in 1974. Pakistan followed suit in 1998 – and it wasn’t long before it was threatening to use it.

In 1999, as the two nations were embroiled in a border war, the Pakistani army crossed into Indian-controlled Kashmir and set about readying its nuclear arsenal. Pakistan will “not hesitate to use any weapon in its arsenal to protect its territorial integrity”, was one Pakistani official’s ominous pronouncement.

But there was another, even more terrifying, ingredient to the crisis. When US president Bill Clinton attempted to mediate, he found that the Pakistani prime minister, Nawaz Sharif, was unaware of the nuclear deployment. It later emerged that the decision to deploy the nuclear arsenal may have been taken unilaterally by the head of the Army Staff, Pervez Musharraf.

Fears that the crisis may escalate into a nuclear war receded when Sharif ordered the army to withdraw in July. But concerns over the role that nuclear weapons may play in Pakistan’s internal struggles remain.

Simon Beard is a research associate at the Centre for the Study of Existential Risk at the University of Cambridge, and a BBC Radio 3/AHRC New Generation Thinker for 2017.