Can humanity survive unrestricted population growth?

• Author: Weiskel, Timothy C.

BIOLOGISTS are reassuring that the invertebrates and microbial species are likely to survive the current epoch relatively unscathed. This message provides small comfort when one begins to realize that the larger point is that life as we know it is undergoing massive extinction. More precisely, geologists, evolutionary biologists, and paleontologists are reporting evidence in their professional journals that the planet currently is in the midst of a global "extinction event" that equals or exceeds in scale those catastrophic episodes in the geological record which marked the end of the dinosaurs and numerous other species.

At least two important differences exist between this extinction episode and those previously documented. First, in earlier events of similar magnitude, the question of agency and the sequence of species extinctions have remained largely a mystery. In the current extinction event, however, scientists know with a high degree of certainty what the effective agent of system-wide collapse is and have a fairly good notion of the specific dynamics and sequence of these extinctions.

Second, previous events of this nature seem to have involved extraterrestrial phenomena, such as episodic meteor collisions. Alternatively, the long-term flux of incoming solar radiation that results from the harmonic convergence of the Earth's asymmetrical path around the sun and the "wobble" on its axis also drives system-wide changes generating periodic advances and retreats of continental ice sheets in high latitudes. These, too, cause system-wide transformations and have precipitated extinction events in the past.

In contrast to these extraterrestrial or celestial phenomena that served as the forcing functions behind previous mass extinctions, the current event results from an internally generated dynamic. The relatively stable exchanges among various biotic communities have shifted in a short period of time into an unstable phase of runaway, exponential growth for a small subset of the species mix--human beings, their biological symbionts (organisms living in a cooperative relationship), and their associates.

The seemingly unrestrained growth of these populations has unleashed a pattern of accentuated parasitism and predation upon a selected number of proximate species that were deemed by them to be useful. This accentuated parasitism led to the creation of human-influenced biological environments. These, in turn, drove hundreds of other species directly into extinction--sometimes within periods of only a few centuries or decades. More significantly, this pattern of unrestrained growth and subsequent collapse has repeated itself again and again, engendering in each instance a syndrome of generalized habitat destruction. Over time, it has precipitated the cumulative extinction of thousands of species as one civilization after another has...