In 1983, scientists gave the world a new reason to fear nuclear war. It had long been assumed that the immediate, direct effects of a nuclear blast would cause a devastating loss of life, and that radioactive fallout would linger. But these scientists stressed that smoke from nuclear-ignited cities might effect something that seemed far more remote—the climate around the globe.
What they found was harrowing. Their models showed that smoke from burning cities and forests could loft high into the atmosphere, shrouding the world in a twilight at noon. Freezing temperatures would kill crops, causing mass starvation and social unrest, and possibly lead to the extinction of mankind.
Called Nuclear Winter, this theory became a heated scientific topic, a pawn in Cold War brinkmanship and a lesson in how scientific understanding changes over time. But decades after detente finally ended the Cold War, it is clear that the theory of Nuclear Winter continues to raise new questions—not only about the devastation that would follow nuclear war, but also more fundamental ones about man's ability to alter the earth's climate, for both good and ill.