And then there were too many

Doomed to what?

Numerous Cassandras and countless Jeremiads have been falsified by history. With proper governance, scientific research, education, affordable medicines, effective family planning, and economic growth - this planet can support even 10-12 billion people. We are not at risk of physical extinction and never have been.

What is hazarded is not our life - but our quality of life. As any insurance actuary will attest, we are governed by statistical datasets.

Consider this single fact: About 1 per cent of the population suffer from the perniciously debilitating and all-pervasive mental health disorder, schizophrenia. At the beginning of the 20th century, there were 16.5 million schizophrenics - nowadays there are 64 million. Their impact on friends, family, and colleagues is exponential - and incalculable. This is not a merely quantitative leap. It is a qualitative phase transition.

Or this: Large populations lead to the emergence of high density urban centers. It is inefficient to cultivate ever smaller plots of land. Surplus manpower moves to centers of industrial production. A second wave of internal migrants caters to their needs, thus spawning a service sector. Network effects generate excess capital and a virtuous cycle of investment, employment, and consumption ensues.

But over-crowding breeds violence (as has been demonstrated in experiments with mice). The sheer numbers involved serve to magnify and amplify social anomies, deviate behavior, and antisocial traits. In the city, there are more criminals, more perverts, more victims, more immigrants, and more racists per square mile.

Moreover, only a planned and orderly urbanization is desirable. The blights that pass for cities in most third world countries are the outgrowth of neither premeditation nor method. These mega-cities are infested with non-disposed of waste and prone to natural catastrophes and epidemics.

No one can vouchsafe for a "critical mass" of humans, a threshold beyond which the species will implode and vanish.

Luckily, the ebb and flow of human numbers is subject to three regulatory demographic mechanisms, the combined action of which gives hope.

The Malthusian Mechanism

Limited resources lead to wars, famine, and diseases and, thus, to a decrease in human numbers. Mankind has done well to check famine, fend off disease, and staunch war. But to have done so without a commensurate policy of population control was irresponsible.

The Assimilative Mechanism

Mankind is not divorced from nature. Humanity is destined to be impacted by its choices and by the reverberations of its actions. Damage caused to the environment haunts - in a complex feedback loop - the perpetrators.

Examples: Immoderate use of antibiotics leads to the eruption of drug-resistant strains of pathogens. A myriad types of cancer are caused by human pollution. Man is the victim of its own destructive excesses.