In the early 1990s, I was lecturing at one of the British defence colleges on the problems of controlling nuclear proliferation. In the process I discussed some of the dangerous crises of the cold-war era that had ended a couple of years earlier.

While focusing on the Cuba missile crisis of October 1962, almost in passing I mentioned a Nato operation of November 1983 - Able Archer. During the question-and-answer session a British army major asked me to elaborate. This was unsurprising: the army itself was most concerned about nuclear weapons, since if any conventional war on the north German plains had gone nuclear the army's own personnel would probably have been killed en masse.

I said what I could, about how a dysfunctional and semi-moribund Soviet leadership had misinterpreted a major Nato exercise involving the new and highly accurate cruise and Pershing-2 missiles as preparation for the real thing - and that in response the Soviets had prepared for war. Nato understood that and quickly scaled down the rehearsal.

At the end of the session, the college’s commandant, a rear-admiral, told the whole group that he had been assigned to Nato HQ at the time and wished to comment on what I had told the class. I awaited his comments with not a little trepidation, only to hear him confirm everything I had said and more. The Nato commanders had indeed been shocked to realise how Moscow had misread Nato’s exercise, and took steps to prevent such a problem arising again.

The nuclear warning

There is now further confirmation of the details of this crisis, thanks to some careful research by Peter Burt at the Nuclear Information Service (NIS) (see Jamie Doward, “How a NATO war game took the world to the brink of nuclear disaster”, Observer, 3 November 2013). In fact, the new work adds little to what was already known about its development, but it does give a very significant insight into the reaction of Britain's then prime minister Margaret Thatcher.

Thatcher, finds the NIS, was so concerned about the risk of untoward escalation that officials were ordered to “consider what could be done to remove the danger that, by miscalculating western intentions, the Soviet Union would over-react”. They were also told to “urgently consider how to approach the Americans on the question of Soviet misapprehensions about a surprise NATO attack”.

It is difficult to say whether this had much effect on Washington. But when, two years later in March 1985, Mikhail Gorbachev came to power in the USSR and made overtures on the nuclear issue, his stance was welcomed in the west rather than rejected out of hand. Indeed, the Reykjavik summit of October 1986 was the springboard to the 1987 treaty on intermediate nuclear forces (INF) - an arms-control rarity in that the respective presidents, Gorbachev and Ronald Reagan, were agreeing to withdraw state-of-the-art rather than obsolete weapons. Within a few years, all the cruise and Pershing-2 missiles and their Soviet SS-20 counterparts were withdrawn and then destroyed. A single incident had helped bring about a major change of policy.

The process thus turned out to be not unlike the so-called “Kennedy experiment”  following the 1962 missile crisis over Cuba, when the shock of near-nuclear escalation led John F Kennedy to make a gesture to his Soviet counterpart Nikita Khrushchev. In a speech at the American University in June 1963, the United States president called for greater understanding between the two states, confirmed that talks would start on negotiating a nuclear-test ban, and announced that the US would meanwhile cease atmospheric testing of nuclear weapons.

In the ensuing months, both the Soviets and Americans made further placatory moves and undertook detailed negotiations on a test ban in Geneva. A comprehensive test ban proved a step too far, but a limited test-ban treaty (LTBT) was agreed by August 1963 and came into effect just two months later. Its terms committed the US, Soviet Union and UK to prohibit all atmospheric nuclear tests and limit the size of underground tests. This rapid progress - four months from initiative to treaty - might well have gone further had Kennedy not been assassinated in Dallas on 22 November 1963.

The climate clock

The common important feature of Cuba and Able Archer is that each incident was sufficiently shocking to encourage major state leaders to take risks in dealing with an existential threat. The achievements may have been partial but the evidence of how quickly attitudes could change, at least behind the scenes, is striking.

The response to these crises played a part in ensuring that today, the worst of the nuclear-arms race has receded - even if the problems of a proliferating world, not least in the middle east and south Asia are all too evident. This experience raises the question of whether the newer global threat - climate disruption - will provoke crises of a scale grave enough to persuade leaders to respond in a similar manner (see "A century on the edge: 1945-2045”, 29 December 2007).

Two factors suggest that history may not repeat itself in the same way. First, the world was in a sense exceptionally lucky with Cuba and Able Archer: neither resulted in catastrophe or even significant loss of life, yet each came close enough to incite a serious change in atitude. Second, it is difficult to see envisage any single climate event both non-disastrous for many people yet so severe that it decisively changes the mindset of international leaders.

At the same time, the signs are that at some time in the next few years there will be one or more extreme weather events which might just shake governments out of their complacency and result in radical action towards decarbonising the global economy.   Whether those events have to be catastrophic in their human impact, or still have the necessary effect without that, will depend very much on the ability of pressure on governments to create prior momentum - such that a single catalyst is all that is needed.

For the latter to be the case, there is much work to do. Perhaps here lies a true precedent, in the dedicatio of those scientists and activists who consistently highlighted the dangers of the nuclear-arms race in the early 1960s and again in the 1980s. The same constancy will be needed, even if the vindication will come perilously late in the day.