Nuclear threat
In the 1960s and 1970s it was widely believed that, if launched, a full-scale nuclear exchange between the United States and the Soviet Union would destroy a large proportion of each country’s population and infrastructure. This idea, known as mutually assured destruction (MAD) deterred war, at least between the major powers.
However, the systems designed to detect a nuclear strike were prone to error. For example, the infamous Able Archer 83 NATO military exercise was mistaken for a real-world first-strike by the Soviets and could have led to the beginning of a nuclear holocaust. Moreover, the launching of just one low-yield nuclear weapon by either side could escalate into a global nuclear war that might kill 99% of the world’s existing population.
For the few survivors left in cities that suffered an all-out attack, conditions would be similar. There would be few healthy neighbouring cities to call upon for help, so supplies of water, food and electricity would quickly run out; firefighting equipment and transportation into stricken areas would be unavailable, or blocked by debris. There would be little or no access to medical treatment for the many cases of severe burns and radiation-related illnesses that would require specialised care. And there would be no way to monitor the progress of the war, other than by radio and TV broadcasts, which might be jammed by debris or lost in a blackout.
Research suggests that even the smallest of nuclear attacks would cause significant climate change and disrupt agricultural production, potentially leading to mass starvation. In a scenario simulated by the group International Physicians for the Prevention of Nuclear War, as few as 100 weapons used anywhere on Earth would lead to a global nuclear winter in which global temperatures plunged by about 13 degrees Fahrenheit, much larger than in the last Ice Age.