Scenarios and population biology

The possibilities are infinite; the single course of events that will be realized is unguessable. We can, however, look at a a few possibilities, using a device known as a “scenario”. Scenarios are hypothetical sequences of events used as an aid in think about the future, especially in identifying possible decision points. I’d like to offer three scenarios, giving three possible projections of what the next fifteen years or so could be like. On is in the form of a short story, one a sequence of hypothetical news items, and one a condensed history written in the future.

–Paul Ehrlich, *The Population Bomb* (1971 Revised Ballantine edition, p.48)