In the event of a significant nuclear war, researchers (Paul Crutzen and John Birks initially) predicted that a barrier of smoke (from incinerated urban centers and forests) would fill tropospheric skies, and eventually surround the earth, reducing the tropospheric temperature and causing damage to ecosystems and atmospheric components such as stratospheric ozone. [Ambios, v11, pages 115-125, 1982.] [Science; v247; 166-176; 1990.] [Chemistry in Britian; pages 927-930; November 1983.]