There has been much consternation about shrinking population in many parts of the world and what that might mean for those nations and for humanity as a whole. In this article I argue that this is not an existensial crisis for humanity. That the current shrinkage in population is in response to the changing role of women in society brought about by drastic change in the social structures in the last century or so. However there are powerful self correcting mechanisms in place that are already kicking in which will stabilise the human population at a new equilibrium, albeit one which might be a much lower level than the current 8 billion of us in the planet. That might not be a bad thing.
First let us spell out the cause of concern for humanity as a whole and a sense of existential crisis for some nations in particular.
* The populations of many nations is shrinking irretrievally.
* The pattern seems inevitable. As a nation gets prosperous, it has less babies per woman. As more and more nations join this prosperity, they inevitably seem to fall into this low fertility trap and their population shrinks.
* While Africa and some parts of Asia still seems to have high enough fertility rates, the same patterns are visible even in these countries as they slowly rise up the prosperity ladder.
* If one extrapolates the current trend then humanity as a whole will start shrinking by the end of this century, while many countries are already doing so causing wide spread social problems as there aren't enough young people to support an ageing population who are living longer thanks to modern medicine.
* The issue becomes alarming when one realises that there are countries like South Korea and Italy where the fertility rate has reached well below 1 per woman and if this is the inevitable fate of all nations then not only will the population of every country shrink, but it will become half every generation because a fertility of 2.1 per woman is required to maintain a stable population.
* This can mean that within a few hundred years the human population will reach levels of the Bronze age last seen five thousand years ago, at which stage the level of human production would drop to such a level that we cannot sustain a modern level of lifestyle.
While it is easy to explain the mechanical reason for this scenario i.e. low fertility rate, the aggregate fertility rate of a nation hides a more nuanced picture. That picture becomes clearer when one breaks up the statistics into women who have 0 offsprings in their lifetime, 1 offspring and 2 or greater offsprings.
In UK where reliable preindustrial census data is available, one finds that in the 18th and 19th century, the number of women who went childless their entire life was one in 20 or about 5%. That figure in the same nation today stands closer to one in every four women today or 25% and if one were to exclude recent immigrants would get closer to one in three. The number of women having one child hasn't changed drastically over the century. Usually these are women who would have wanted more children but were prevented either by medical or some personal circumstances from having more.
The average number of children for those women having two or more has also decreased since people no longer have 6 or 7 children, but given that infant mortality was much higher previously, the number of surviving children hasn't decreased that drastically.
Hence once one goes deeper, one realises that the drastic decrease in fertility is caused disproportionately by a very large proportion of women in a population going childless, which the rest of the women cannot compensate for. As an example one third of south korean women go childless while two third of the women have at least one or two children. That is a far cry from the perception that south korean women have stopped having babies. However that two third cannot compensate for the one third who don't have children leading to the abysmal fertility rate of 0.7 in that country.
The cost and effort of raising children is definitely a factor amongst women who have only one or two children. Studies have shown that many such women (the proportion varies from country to country) would have preferred to have more kids if it was cheaper or they had more money and help in raising children. However the cost factor cannot explain for the women who have no children at all. Most studies classify such women as being in a higher socio economic bracket often earning more than the average earnt by women who have children.
The consensus explanation for these childless women is them prioritising their career over children. There is not much dispute on this. What some new studies have however revealed is the proportion of these women who never wanted children in the first place compared to those who thought they would eventually have children but ended up growing old without having one. This survey was done both in developed countries as well as middle income countries like Indonesia and Thailand. The reasons were surprisingly similar in both regions. Over 9 in 10 women thought they would eventually have children sometime in their lives. While a small proportions never found the "right" partner, for most they left it till too late and could never get pregnant as they got old. It seems human fertility is a lot more fragile than we think. What is annoyingly easy in the teens and twenties becomes increasingly difficult in the thirties and rare in the forties.
So what does this bode for human population and humanity itself? Surprisingly if one forwards the story by a few centuries, I would argue there is no reason for concern about human population at all. We humans are governed by the same Darwinian population dynamics as every other organism on the Earth that we share. That evolutionary dynamics readjusts the population of every organism whenever the environment or the reproductive habits of the organism changes to reach a new equilibrium.
We haven't been struck by some alien virus that has rendered humans infertile. All that has happened is that due changes in society and socio-economic ambitions of a propotion of the women population, a certain proportion of women end up being childless. Note that even now more than half the women in even the most advanced societies prioritise children over their careers early enough not to go childless.
Evolutionary law dictates that only those women who choose to reproduce pass on their genes as well as being a role model to both their daughters as well as their sons. This should mean that every generation is being populated only with the genes and social example of women who chose to reproduce. While humans are social animals and these daughters would still have some opportunity to see their childless aunts as role models, there will be strong evolutionary pressure to replace the human gene pool with both genes as well as social norms that prioritise reproduction.
Another social pressure again driven by evolutionary instincts will come from the other half of humanity -- men. The evolutionary compulsions of reproduction are programmed in men just as much as women and every other living organism. The pool of women who prioritise having children early is also the best ticket for men to ensure their own genetic survival by having the best chance of having offprings. As this pool of women shrinks in developed countries, there will be more men competing for this pool of women changing their status from lower status to "premium" status. This will eventually put a floor to the shrinkage of this pool of women.
As and when such premiumisation of this pool of women happens, it will also attract higher status men with higher income. This will enable such women to have more children if they desire. Eventually this will lead to a new equilibrium that can reach the fertility rate of 2.1 again and stabilise the population. This might take a long time, perhaps centuries during which time the overall population of humans might even shrink. However as expounded above, the counter forces of evolution will not let the population growth rate to decline to such drastic levels that we will have a catstrophic collapse. Instead humanity might stabilise at a population a few billion lower than today, which might not be a bad thing at all!
No comments:
Post a Comment