Ever since Thomas Malthus, an otherwise blessedly obscure 18th century British philosopher, popularized the notion that population increases geometrically while food supply increases only arithmetically, ever-increasing hordes of demographic doomsayers have tried to persuade us that we will be the death of us all.
Malthus' prediction of inevitable mass starvation never came true. Technology has increased food production far beyond Mr. Malthus' grim imaginings; such famines as have occurred have been, for the most part, deliberately man-made, often for political reasons.
Nor has the more recent "Population Bomb" crowd given birth to more accurate prophecies. Dire predictions that population would keep on rising until it occasioned a global catastrophic collapse today seem about as realistic as the belief that if God had wanted us to fly, we would have been born with airline tickets.
Not so long ago, demographers, especially those with a liberal agenda, saw human numbers rising as high as 30 billion. Today, however, global population growth has slowed dramatically; the emerging consensus is that population (currently about 6.3 billion) may stabilize around 9 billion by 2070, and then decline.
No one is sure why this is happening. The "usual suspect" causes — war, disease, government policy, contraception, abortion, infanticide — certainly contribute. The last two especially, since in places like China and the Arab world they're used for sex selection, resulting in a preponderance of men over women.
Over 50 years ago, demographer Frank Notestein described three phases of population growth. In phase one, associated with primitive societies, birth and death rates are both high, causing population to stabilize at low levels. In phase two, associated with developing societies, birth rates stay high, but, due to improving productivity, sanitation, nutrition, education and medical care, death rates drop; population soars. If a country develops further economically, phase three ensues and population stabilizes with low birth and death levels.
Today, the developed world averages a Total Fertility Rate (TFR) of about 1.6 children per woman, less than the replacement level of 2.1.
According to demographer Nicholas Eberstadt: "Europe's overall TFR stands in the 1.4 to 1.5 range, with Italy and Spain on the low end, at about 1.2, and France and Ireland on the high end, at about 1.8. The U.S. fertility rate has been over 2.0 since 1990 and is just under replacement today — somewhere between 2.0 and the 2.1 replacement level, making it about 40 percent higher than Europe's."
Birth rates in less-developed areas, including parts of the Arab world, are also dropping below the replacement level. True, less developed areas will have younger populations than the West for the next several decades. But across the globe, the trend is now toward stable and older populations.
But, like human beings, these predictions are imperfect; nobody knows for sure what the future will bring.
Even so, there are likely to be problems, such as a "demographic time bomb" not caused by rapid population growth, but by slow decline, and the possibility that a birth dearth resulting in proportionally fewer young people may bring on societal poverty.
So, what's the problem?
In essence, this: Despite all the blather and worry about excess population, economic and technological advance have been intimately associated with increasing populations in the past. Every baby is born with one mouth to feed but also with two hands to work, produce, prosper and create. At the same time, older populations, almost by definition, do less work per capita and require more care than younger ones.