Nuclear Winter: A Matter of Degrees

Abstract

Although climatic impacts have long been on the list of potential consequences of nuclear war, two years ago they were predicted to be so devastating as to earn the label, “nuclear winter.” That term describes a world that is plunged into cold and darkness because the sunlight is blocked by smoke from fires ignited by nuclear explosions and by the dust from nuclear groundbursts. This vision is considerably more severe than any painted earlier because the calculations for the first time included massive injections of soot, the carbonaceous component of smoke. The soot strongly absorbs the incoming sunlight but transmits most of the outgoing infrared radiation, creating an inverse greenhouse effect.