Cities across America have burned to ash, and forest fires consume rural areas. The constant burning produces so much soot that it rises into the atmosphere and blocks the sun. The resulting condition is a “nuclear winter,” a massive plunge in global temperatures lasting as long as 10 years. The earth’s ecosystem would suffer incalculable damage, and human beings would fight off bitter cold, ubiquitous radiation poisoning, and fellow citizens for a share of the meager remaining resources. Drastic reductions in rainfall would destroy agriculture, and there would be no way to distribute any preserved food. Clean water will be equally rare, poisoned by both radiation and billions of corpses. Countless species of plants and animals will go extinct, becoming nothing more than a fossil.

Eventually, nuclear winter will soften, but the ozone will be so depleted that life on the earth’s surface will be all but impossible, driving whatever is still living underground. New sunlight will bring about new species of insects, many carrying disease. There is no way to know if humanity will survive.