Population: Too Many or Too Few?
Nayyer Ali, MD

The 20th century has been extraordinarily good to humanity, at least judging by the number of people on the planet. In 1900, a mere 1.5 billion people lived on the planet, but now the total has exceeded 6 billion. No other century has ever seen that degree of rise, or ever will. This population explosion has been driven almost entirely by better health with resulting longer lifespans. Life expectancy for the globe has jumped from 30 years to 63 years. Public sanitation, vaccination, clean water, and better nourishment are the main factors behind all this. Although it seems to many of us that having grandparents around for many years is a normal state of affairs, this has only been true for the last 50 or 100 years. Prior to that, most people were already dead or lived only a short while after having any grandchildren.

The question now is what will the next century bring. Although there has been a great deal of ink spilled on the problem of “overpopulation”, the surprising truth is that there now may be two entirely opposite population problems brewing. The first is the classic one of “too many”, but for much of the world, the problem may be “too few”.

The single most important number in judging long term trends in population is the Total Fertility Rate or TFR. This number represents the average number of babies born per woman during her lifetime. Replacement TFR, the number that allows each generation to exactly reproduce itself, is 2.1. Countries with TFR’s above 2.1 will have expanding populations, while those with numbers below 2.1 will have declining populations. The shocking fact is that currently 45% of the world’s population lives in countries with a TFR below replacement!

Every single industrialized country is below 2.1, with Germany, Italy, and Spain at an exceptionally low 1.2. China with its one child policy has pushed TFR to 1.8. Russia is at 1.3, and even the United States is at 2.08. These numbers will cause significant declines in population in the next century. Without immigration, Germany would see its population almost cut in half, with a huge fraction of elderly and relatively few children among those remaining. Russia has already seen population decline in the 1990’s.

The major consequence of this low fertility in the next century will be the exact opposite of high fertility. Rather than growing populations that are disproportionately young, we will see countries with shrinking populations that are relatively old. Some projections suggest that Japan, where these trends are quite strong, may have over 30% of its population above the age of 65 within 50 years. Many governments see this and wonder how and who is going to pay the taxes needed to provide for all these elderly. The shrinking pool of young people who are working will be doubly burdened. These fears have caused many European governments to adopt pro-baby policies to encourage people to have more children. But no matter how hard they try, there has been no sign of success. Their only other option is massive immigration of young workers from the 3rd World, and we are starting to see this happen.

For the 55% of the world that lives in countries with higher fertility levels, the overall trend is still sharp decline in TFR. In the last 30 years TFR has dropped 60% in Brazil, Mexico, Turkey and Iran. It has dropped 70% in Thailand and 50% in Egypt. It has dropped about 35 to 45% in most other Arab countries. These tremendous reductions have left TFR about 2.5 to 4.0 in most 3rd World countries. Given the pace of decline, these numbers will likely drop to replacement in the next 1 or 2 decades.

Currently for the entire globe, TFR is about 2.9. If it reaches replacement in the next ten years and declines further to about 1.8 in 2020, some rather interesting things will happen to the human race. Given those assumptions, world population will peak at 7.7 billion around 2040, and decline to less than 6 billion by the end of the 21st century. We might end this new century with fewer people on the planet than we start with. This is in fact the “Low Variant” estimate made by the United Nations. Even the high variant has world population peaking around 2070. The big picture suggests that although some regions of the world may be overcrowded, the population explosion for the most part is coming to a rapid end, and the future may be one of managing declining population. This will be a whole new set of problems. Next week this column will look at Pakistan’s population future.

Comments can reach me at Nali@socal.rr.com.