Nuclear winter refers to the deadly worldwide climate change that would result from a major nuclear war. Even a relatively small nuclear war between neighboring countries would change climate dramatically.
Nuclear winter would develop from fires created by nuclear explosions in cities and industrial areas. Large amounts of smoke from these fires would spread to cover the entire planet. The smoke would prevent most sunlight from reaching the ground. Temperatures would drop substantially, and rainfall would be reduced. These conditions would last for several years or more. With greatly reduced sunlight, less rain, and lower temperatures, farming would stop, and worldwide famine would result. Nuclear winter also would reduce Earth’s ozone layer, which protects people and other forms of life from the sun’s dangerous ultraviolet light.
Scientists estimate that the nuclear explosions in a major nuclear war could kill 500 million people. But 4 billion more people could starve to death in the next year because of nuclear winter. Thus, nuclear winter could endanger every country.
