A regional nuclear war involving as few as 100 Hiroshima-sized weapons would disrupt the global climate and put a billion people at risk of famine.
Nuclear weapons are the only devices ever created with the capacity to destroy all complex life forms on Earth within a relatively short period. A war fought using 1,000 nuclear weapons – around 5 per cent of the total global stockpile – would render the planet uninhabitable. A regional nuclear war involving around 100 Hiroshima-sized weapons would disrupt the global climate and agricultural production so severely that more than a billion people would be at risk of famine, according to recent research by the International Physicians for the Prevention of Nuclear War. Although it would not result in the extinction of the human race, it would bring about an end to modern civilization as we know it.
Reduced sunlight and rainfall
The smoke and dust from a limited nuclear war would cause an abrupt drop in global temperatures and rainfall by blocking up to 10 per cent of sunlight from reaching the Earth’s surface. Sudden global cooling would shorten growing seasons, threatening agriculture worldwide. Increases in food prices would make food inaccessible to hundreds of millions of the poorest people in the world. For those who are already chronically malnourished, just a 10 per cent decline in food consumption would result in starvation. Infectious disease epidemics and conflict over scarce resources would be rife.
If the entire global nuclear arsenal were used, 150 million tonnes of smoke would be emitted into the stratosphere, resulting in a 45 per cent global reduction in rainfall and average surface cooling of –7 to –8°C. By comparison, the global average cooling at the depth of the last ice age more than 18,000 years ago was –5°C. A nuclear war would cause prolonged and severe depletion of the ozone layer and have a devastating impact on human and animal health. Substantial increases in ultraviolet radiation would cause increases in skin cancer rates, crop damage and the destruction of marine life.