A friendly acquaintance – who keeps the best Facebook I know – recently called me a “soothsayer.” That hurt! Her intention was to scum me out for throwing the cold cloth of skepticism over her apparent concern for overpopulation. I had opined that the world population will begin to decline around 2050.
It wasn’t difficult to opine. I am not a demographer by training but gross demographic projections are not difficult to understand. Again, it’s not mysterious. Here is my try at explaining world population growth until only about 2050.
The number of births in the next thirty years or so is completely constrained by the number of women of child-bearing age now. We have a very good idea of what that number is already. In most alternative scenarios but one (see below) there will be even fewer women of child-bearing age than expected. And, yes, you got it, the number of men does not matter much. That’s because even a very few courageous, determined males can accomplish prodigious wonders in the area of procreation. The more women in that age range, the more births.
How many children any woman will have in her lifetime depends mostly on two things plus one. First, the higher the age at marriage, the fewer children. Second the more educated the woman the fewer the children. Lower the age at marriage and take girls out of school, and you will see more births. Make marriage later and keep girls in school and you will have fewer births per woman on average. For the past fifty years, world trends have been later age at marriage and more education for girls. (But see below.)
Finally (“plus one”), everywhere in the world, a high degree of urbanization reduces the number of births per women. Women in the cities have fewer children than their own cousins in rural areas.
These three factors together are enough to predict very well, to forecast, future population growth. They have been use successfully to forecast slower population growth in such diverse countries as Egypt and Mexico. Of course, practically all the European countries’ and Japan’s populations are decreasing, have been for a long time. The major exception is France where a large immigration from poorer countries is combined with a lavish welfare expenditures to support child rearing. The combination sustains the French birth rate above replacement rate. This means that left to their own devices and to men of their own origin, French women whose grandparents were all born in France don’t contribute enough children to replace themselves and their male breeders.
Using this simple, understandable model based on things that are easy to measure, demographers have been predicting a reversal of global population numbers sometimes around 2050.
Of course,there are many other factors that influence population growth. Almost all of them reduce it. Together, they would have the effect of lowering world population before 2050.
There are presently no forces – except one – that would reverse the trend toward a smaller global population. The one exception is Islamism whose program involves lowering the age of marriage for women and limiting girls’ education. (See above.)
When specialists agree without any acrimony on a model that is easy to understand, based on a small number of variables and these variables are straightforwardly constructed from readily available, good-quality data, you have an issue not much worth worrying about. You can worry instead about the horrible forthcoming destruction caused by global warming about which 97% (or is it 98%?) of scientists agree although none is able to explain it with any clarity. (See my postings.)
Of course, you are also free to consider the world unbearably overpopulated today, already, because of a formidable drop in infant mortality, because of slowly but steadily growing longevity, in spite of the fact that the world produces enough food for everybody on it. You might even decide that population density is too high for simple comfort. That would be in spite of the fact that you could easily house the whole world population within the state of California at a normal America suburban density. (Don’t take my word for it, do the long division yourself.)
I am not a soothsayer, Carol. I try to stay informed. I read good stuff. ( Personal note: That includes Skeptic magazine, thanks to you!) I am extremely skeptical of all apocalyptic predictions. In my lifetime, I have witnessed almost only improvements. You should read my book . (I Used to Be French: an Immature Autobiography, available on Amazon and from me at email@example.com)
Oops, the ingrate! Of course, Carol, you are already reading it! Thank you very much.