''On The 8th Day'' is chilling, a result entirely consistent with its aim. The one-hour documentary explores the possible ecological and atmospheric consequences of nuclear war, particularly as they would be expressed in a ''nuclear winter.'' Darkness would shroud the Northern Hemisphere; temperatures would fall. The planet would survive, but not as a hospitable place.

''On the Eighth Day'' was originally produced for the BBC as part of the series The Natural World, and aired in the United States on cable station TBS on January 14, 1985.