Crutzen was also a leader in promoting the theory of nuclear winter. Together with John W. Birks he wrote the first publication introducing the subject: The atmosphere after a nuclear war: Twilight at noon (1982). They theorized the potential climatic effects of the large amounts of sooty smoke from fires in the forests and in urban and industrial centers and oil storage facilities, which would reach the middle and higher troposphere. They concluded that absorption of sunlight by the black smoke could lead to darkness and strong cooling at the earth's surface, and a heating of the atmosphere at higher elevations, thus creating atypical meteorological and climatic conditions which would jeopardize agricultural production for a large part of the human population.
In a Baltimore Sun newspaper article printed in January 1991, along with his nuclear winter colleagues, Crutzen hypothesized that the climatic effects of the Kuwait oil fires would result in "significant" nuclear winter-like effects; continental-sized effects of sub-freezing temperatures.