Sudipto Majumdar's Blog

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!

I grew up in a middle class family, in a middle class neighborhood of a large city in the late 20th century. I studied in a public school where the curriculum was modern and non-religious. My father was a professional holding a typical executive job, while my mother was a home-maker. Both my parents believed in God as did my grandmother who lived with us. Neither of my parents was deeply religious, although they did pray and went to a temple when their schedule allowed them to. They participated in religious festival and rituals, and performed the customary religious rituals on special occasions. My parents however were reasonably liberal in their views and never tried in any way to impose their religious beliefs on any of their children.Growing up in this reasonably liberal environment I never felt the need for religion or God. As a teenager I found the Hindu mythologies and concept of God ridiculous and beyond logic. As I learnt about other major religions, I found their mythologies and concept of god equally illogical. At that time my father had said that when I grow older I would start believing in God.I am now in my mid-forties and it hasn’t happened yet. I am still as much an atheist as I was then, although my understanding of religion and atheism is probably a lot more nuanced than what it was a teenager. As a teenager, I used to say that I believe in science and not in God. I would aver that if there is a God or religion that I believe in, then it is science.Over the years I saw many of my friends and classmates who grew along with me become deeply religious, while others turned atheist like me. When I am talking about turning religious, I mean people who truly and deeply believe in God, not the people who are actually agnostic or mild believers but profess publicly to a belief in God, just in case He exists.I have found no correlation between the education level, family background or intelligence and being either deeply religious or atheist amongst all the people I know. There are many with similar background as mine who are deeply religious, and others from deeply religious families who are atheists.This got me thinking on a very fundamental nature v/s nurture question. My personal and empirical evidence suggested that nurture had a very small role to play in a person being deeply religious or an atheist. That meant that it must be something very deep in our human nature that makes us believe in God, even though at another level the same individual could be a highly logical, rational and a scientific person.To say that the human brain is complex would be an understatement. What we also know is that the brain is the least understood part of the human body. A neuroscientist would be the first to tell you that we understand as much about the human brain as probably primitive cavemen understood about the human heart.This lack of understanding about our own brains and hence our thought process reflects in the literature I have studied of anthropologists, evolutionary biologists and neuroscientists. None of them claims to definitively know why human beings invented the concept of God and find the need to believe in Him. The prevalent speculation amongst scientists is a follows.Somewhere along the road to our evolution as modern humans, our brains developed the capability to believe in multiple concepts at the same time, even if some of those concepts were contradictory. These concepts do not just apply to the concept of God, but to almost any human endeavor one can think of. For example most of us abhor violence, but yet we can justify killing when one tribe wages war on another. One may be unable to cut the neck of a chicken, and yet be able to eat chicken fry at the dinner table.Clearly being able to believe in contradictory things simultaneously had an evolutionary advantage, because all humans alive today have this ability. Thus a primitive farmer may pray to the fertility goddess for a good crop and believe that only her blessings would ensure a good harvest. Yet at the same time the farmer also knows that he has to water his fields to ensure that the crop grows. Just praying to the goddess would not help.This still does not explain why human beings needed to invent God in the first place. My theory is that as human brains evolved, and they were able to piece together more and more complex logic, they figured out many cause-and-effect sequences that affected their lives. The farmer figured out that seeds are what grow into plants, hence he has to sow seeds in order to get crops. The farmer also figured out that plants need water and nutrients to grow, which he would have to provide in his farms.Yet there were many events in the early human beings’ lives which would have seemed completely random. These events for which he could not figure out the cause-and-effect sequence also affected his life. A locust plague would ruin his crops and threaten the survival of his family. A flood could end everything in his life. To cope with these uncertainties which he could neither explain nor control, he invented an all-powerful God whom he chose to appease and hence indirectly control his destiny.This is where being able to believe in contradictory concepts at the same time helps. If one is to believe in God who can do anything, then why not ask the God to sow the seeds and water the farms? Why do the backbreaking work when the almighty can do it for you? Obviously if humans didn’t have the ability to believe in contradictory concepts at the same time, then the moment they invented God they would have stopped working and hence perished.Things have not changed in the modern world. There are many more things we understand today than our primitive ancestors. There are many more cause-and-effect chain of events we can explain scientifically. We can explain and even predict a locust plague or floods. However the more complex our lives have gotten, we have created newer uncertainties which affect us just critically as the primitive farmer.We are just as afraid of being randomly struck down by an accident or contracting cancer. We are equally afraid of our livelihood today. Who knows when one might get fired from his or her job? The amount of uncertainty has not decreased in our lives and I can fully understand why modern humans would take refuge in the certainty of belief in God.So that explains why highly scientific, logical and successful friends of mine are deeply religious. Where does that leave me however? I wish I could say that I don’t have any uncertainties in my life, but that is not true. I have just as many imponderables in my life that could affect me negatively as the next person. So why don’t I feel the overwhelming need to take solace in God and religion? Why do I and atheists like me stubbornly refuse to believe in God and stick to science only.I asked myself the question – is science exactly the same thing to me as religion is to a believer? Just like every other human being, surely I must also be having the need to insulate myself from inexplicable uncertainties of life exactly the same way as my believer friends. Is it that I am also a believer? Is it that I have fulfilled my need to believe by merely replacing religion with science?That can’t be true. The science that we know today cannot explain everything. It does not even claim to know everything. My religious friends believe in science just as much as I do. Religion to these friends of mine is in addition to science. Religion fills up the spaces left empty by science.That is the fundamental difference between science and religion – any religion. Flowing from the concept of an omnipotent God (or multiple Gods depending on whether it is a monotheist or polytheist religion), is the corollary that religion can explain everything. Religion can explain every event in the universe, whether it is a personal tragedy or an exotic question like ‘how did this universe begin and who created it’? It is not just religion can, but religion has to be able to explain everything and hence know everything that happens in this universe, otherwise God has no raison d'être.Science on the other hand is very comfortable with the notion that it knows and can explain only a certain fraction of the observed phenomena in this universe. It is an ever expanding cloud of knowledge as humans learn more, but that cloud is limited in its coverage which does not encompass every observed phenomenon. Science goes one step further and says that all that it knows till date is tentative in nature and could be all wrong or subject to revision, if in future evidence or theory is found that contradicts current knowledge of science. Scientific ethos is not just comfortable with this admission of partial knowledge but actually thrives in it. Scientists work with more enthusiasm and gusto when new unexplained phenomena are discovered.In contrast to the admission of the tentative nature of all science’s knowledge, religion by definition needs to proclaim its knowledge as absolute and certain. The very basis of religion is that its knowledge is immutable.In my mind, mirroring this fundamental difference between religion and science is the difference between atheists and people who are believers. A believer feels the compelling need to be able to explain each and every observed event and phenomenon both in his or her personal life as well as in the broader universe. What can be explained rationally or scientifically is accepted by the believer as such. Whatever cannot be explained by science, the believer takes solace in the explanation provided by religion or God.The Atheist on the other hand is perfectly comfortable if a lot of events and phenomenon in his or her personal life as well in this universe remain unexplained. The atheist would accept such unexplained events as either random which don’t need an explanation or such phenomenon being beyond the knowledge of humans yet, which may be explainable in the future with increased knowledge. In either case those unexplained and uncertain events do not disturb them mentally.
This does not mean that every atheist is burning with scientific temper and hence making an endeavor to explain those events rationally. All it means is that they do not need to take refuge or solace in other explanations. In fact we need to separate out the question of scientific temper from atheism altogether. There are many scientists who are believers and by the same token there are many atheist who couldn’t be bothered with science, they just accept unexplained phenomenon as it is.

The recent farce at Copenhagen forced me to express in public, something I have always wondered about climate change.
Is global warming bad for humanity? Now we have been told ad nauseum that global warming will inflict terrible pain on human race and global apocalypse is nigh. I have a feeling that most of us have accepted this without questioning. May be it is time we did.
First let me make it clear that I am not one of the deniers of global warming. The scientific logic and evidence is clear that the earth is warming. The only difference of opinion amongst scientists is the extent & time table of this warming.
The fact that global warming will lead to climate change is accepted, and it is also amply clear that in the short run (next few decades), this will lead to miseries and suffering amongst all but the wealthiest of people. Some will be affected drastically like the people of Bangladesh and Maldives as their land drowns and they become climate refugees. Others will the pay the price in terms of higher food prices as the changing weather pattern plays havoc with the agricultural cycle as we know it around the world.
So it can be clearly said that the climate change is bad in the short run for humanity.
However from geological evidence we know that the earth has been much warmer before many times and also has gone as cold as to freeze the entire oceans of the earth in what is called the "snowball earth". The higher temperatures may be uncharted territory for human race, but the earth has been there before and from the geological evidence, one can say that life has flourished in temperatures much higher than what exists today. The dinosaurs lived in a time when the temperature of earth was probably a few degrees higher than what exists today, and it was considered a prime environment for life to flourish.
If the global temperatures were to stabilize a few degrees higher than today, then there would be many positives as well as negatives. This in the overall scheme of things after the dust settles and humanity goes through the traumatic change in weather patterns, may balance out and may even give us a greener earth!!! The Sahara would turn green and Greenland would turn green too! This may offset all the fertile land we may lose due to rising sea levels and change in rainfall patterns. After all we have to remember that the overall rainfall on earth would actually increase with a few degree rise in temperature!!!
So can we say that global warming is good for humanity in the long run? Not so fast!!!
I started the previous para with an "if", and it is a big if. We do not know where the temperature will stabilize. As mentioned before, this is uncharted territory. Human species has never encountered this situation before. All we can do is infer from previous geological era; but that can only give us pointers, the situation now is not exactly the same as in previous era so we can never be sure what the final temperature we will stabilize at.
Given this uncertainty, I would say this.... It is better to have a certain future than an uncertain one. To that extent we should try to hold on to what we have today and try to avoid global warming as much as possible. So global warming may or may not be bad for humanity in the long run, but it will certainly bring endless misery in the short run, and that in itself is bad enough.