[ed. note: Michael Jorrin, who I call Doc Gumshoe, is a longtime medical writer (not a doctor) who writes for us about medicine and health a couple times a month. He has agreed to our trading and disclosure restrictions, but does not generally write directly about investment ideas. His ideas, thoughts and words are his own, and you can see all his past pieces here.]

This is by no means a new concern. At the end of the 18th century, the Reverend Thomas Robert Malthus observed that population tended to grow at an exponential pace, while food supply grew only at an arithmetic pace. For example, if a thousand mating couples (2,000 individuals) had three offspring each, that would result in 3,000 children at the end of a generation, and 4,500 children at the end of two generations. In three generations, or about one century, that original population of 2,000 would have more than tripled to 6,750.

That’s more or less what has happened to global population in the past century. In fact, global population was estimated at about 2 billion in 1927, and is now somewhere around 7.5 billion, having passed the 7 billion mark in October 2010, about 12 years after it zoomed by the 6 billion marker. That’s closer to quadrupling in a century than to tripling.

However, the good Reverent Malthus thought that there would be offsetting factors that would prevent the planet from becoming impossibly overpopulated. Because food production could not conceivably keep up with the exponential pace of population growth, there would inevitably be famines. There would also be natural disasters, wars, and diseases. The Four Horsemen of the Apocalypse would keep the population in check.

Malthus was right about the exponential rate of population growth, but wrong about the factors that would offset that growth. Yes, there have been wars, natural disasters, and diseases, as well as famines, but it does not appear that those “Malthusian disasters,” as they are known, have had much effect on slowing population growth.

For example, the Chinese famine during the years 1959 to 1961 may have caused as many as 45 million deaths. (Recent conservative research puts the number at 36 million.) This does not seem to have slowed China’s increase in population by much. In 1959, Chinese population stood at 668 million, and it had increased to 682 million in 1960. Then, in 1961, due to the famine, it declined to 658 million. But by 1963 it had recovered all lost ground and increased to 691 million. The population of China passed the one billion mark in 1982, and now stands at 1.381 billion.

According to the UN’s Department of Economic and Social Affairs, global population is expected to hit 8.5 billion by 2030, 9.7 billion in 2050, and 11.2 billion by 2100. Those, by the way, are mid-range estimates. The high estimate for global population by 2100 is about 14 billion.

As of 2012, the UN’s projections for the regions of the world in 2100 were as follows:

Asia	4.60 billion
Africa	3.57 billion
Latin America	0.69 billion
Europe	0.67 billion
North America	0.57 billion
Oceania	0.07 billion

This puts the total for the Western Hemisphere at around 1.26 billion, while the Eastern Hemisphere is projected to have a population of 8.84 billion. The largest increase is projected to take place in Africa, whose population of about 1 billion today is projected almost to quadruple. By 2050, the population of Nigeria is expected to top 400 million, exceeding that of the US, making it the third most populous country on the planet after India and China. And it’s projected to reach 760 million by the end of the century. India is expected to be the most populous country on earth, passing China in about five years.

The perils of population growth have been the basis for a good deal of dystopian fiction. I recall a story by Philip K. Dick in which office workers essentially lived in their workplace, sleeping in the stairwells, and subsisting on weird artificial foods. A staple was “chicken little,” an immense rapidly growing mass of an edible substance resembling chicken meat into which artificial nutrients were pumped, and which grew enormous volumes of “meat,” which were daily harvested and fed to the workers.

And currently some nervous members of the super-super rich are already in the process of establishing (or at least planning) totally self-contained and self-sufficient “environments,” in which all necessities for life could be generated, and which would protect them from the surrounding hordes. Farming and raising livestock would be carried out in perfectly climate-controlled indoor environments. Or perhaps their inhabitants could dispense with actual food – liquids containing all the necessary nutrients would keep them fit as a fiddle.

But those solutions are only for the privileged few.

Population: total numbers versus population density

Nigeria is not a tiny country, but if its population shoots up to the 400 million plus marker as expected, it’s going to be pretty crowded. Nigeria’s land area is about 357,000 square miles – less than one-tenth of the US land area of about 3.8 million square miles. And as for India, by 2050 it’s expected to have a population in the neighborhood of 1.7 billion crammed into a land area of 1.269 million square miles, less than one-third of the US land area. In each case, that comes out to a population density about ten times that of the US.

So, what are the effects of population density on health?

There are certain clear advantages to living in urbanized areas rather than out in the wonderful middle of nowhere. I am not speaking here of the Black Hole of Calcutta or the shanty-towns of Lagos or the favelas of Rio, but in general of the metropolitan areas of the world’s large cities. One signal advantage, at least in the more developed world, is that the rate of accidental injury is much, much lower in the more urbanized areas. Yes, there are lots of automobile accidents in the big cities, but most of them result in minor injuries. The fatal crashes tend to be in the rural areas.

And once there’s an accidental injury, whether a car crash or something else, a key factor is how quickly the victim gets medical attention. Out in the sticks, if you fall off the ladder while you’re putting up your storm windows, it might be a while before the ambulance shows up, and another while before it gets you to the hospital. This results in about a 20% higher rate of death from accidental injuries in rural areas.

Also, in rural areas, people may have to travel considerable distances to see a physician that is able to treat their particular disease or condition. If a person living in a remote rural area relies on regular visits to a rheumatologist for the management of a condition such as rheumatoid arthritis, this may entail long trips and may simply be impractical for some people.

Survival after heart attacks or strokes is highly dependent on how quickly the ambulance arrives and how quickly the patient gets to the hospital. If you have a heart attack in downtown Seattle, you have a much better chance of surviving than if your MI happens out near the border with Idaho. In more developed regions, there are sometimes means to overcome the distance factor. For example, J. Walter Schaefer introduced an air ambulance service in California in 1947, for the specific purpose of quickly getting people in the rural parts of the state to hospitals, and similar services are now fairly common.

That being said, there certainly are health drawbacks in living in more densely populated areas. Perhaps the single health factor that is most strongly and obviously linked with population density is pollution. According to a 2012 report from the World Health Organization, air pollution was the cause of 3.7 million annual deaths, two-thirds of which occurred in India and China. In the more-developed world, we think of air pollution as resulting from factors like fossil-fuel-dependent electric generation and automobile exhaust, but in the less-developed regions the main sources tends to be home heating and cooking as well as waste incineration. In New Delhi, a study in about 11,000 children concluded that nearly half of that city’s 4.4 million children between 4 and 17 years of age had irreversible lung damage due to air pollution.

Some diseases spread much more rapidly in crowded conditions, for example, tuberculosis – there were 8.6 million cases of tuberculosis in 2012. Diseases carried by vectors such as mosquitoes spread more rapidly when those creatures find more humans to feast on – Zika and West Nile virus being good examples.

Polluted water is a threat to health regardless of population density, but if the source of the pollution is human waste, as is so often the case, the relationship between crowding and pollution is obvious. The source of the cholera outbreak in Haiti was almost certainly a contingent of UN peacekeepers from Nepal. But what has made the outbreak far worse is the extremely crowded conditions, and the scarcity of clean water, whether for drinking or cooking or for any other purpose.

…but will there be room for all of us on Planet Earth?

That depends on which region of Planet Earth you’re looking at. There’s plenty of room in Turkmenistan and in the steppes of Central Asia. Maybe there’s some spare space in Canada and Australia and parts of the US and South America. However, a few days ago I read in the paper that 450,000 people in Bangladesh left the coastal areas seeking higher ground because of a threatening storm. Where they wound up, the story didn’t say. But there’s not much room in Bangladesh. The population is close to 165 million, and the population density per square mile is 3,279. That’s more than 30 times the population density of the US, which is about 90 per square mile. I remember that about 20 years ago, there was a cholera epidemic in Bangladesh which quickly killed something like a quarter of a million people. The rate of population growth in Bangladesh at that time, close to 2% annually, meant that those quarter of a million departed souls would be replaced by a quarter of a million newcomers to our planet in the space of about six weeks.

(Here I must introduce a positive note: the treatment of cholera in Bangladesh has improved to the point where the great majority of patients survive. Take that, Malthus!)

The population growth rate we have been seeing lately is on a collision course with two other major global trends: resource depletion and climate change. The resource people were most worried about was oil, but concerns about oil have eased. However, other resources may be much more important: water and arable land. Take water: DeBeers (the diamond company) did a study in 2006 which predicted that water in rivers in Africa would decrease by about 40% by 2050. Lake Baikal, in Russia, the largest body of fresh water in the world, is estimated to hold about 20% of the total fresh water on the entire planet. It was thought to be too large to become seriously polluted, but evidence is mounting that industrial pollution, particularly from paper mills, is severely damaging the lake.

Clean water issues are endemic, and not only in Flint, Michigan. New artesian wells in India, drilled with the help of international organizations, have been found to contain dangerous levels of arsenic. The Chinese have attempted to convert marginal land to agriculture, but the desert keeps reinvading it. Here in our country, the Rio Grande hardly reaches the Gulf of Mexico, and almost all Colorado River water has been used for irrigation before it reaches the Sea of Cortez. Wherever humans live, there’s a demand for water, and the more humans, the greater the demand.

As for arable land, the UN projects that in the densely populated parts of the world, there is about 0.1 hectare per person. That’s about a quarter of an acre – a small suburban building lot. What is meant by arable land? The rain forests in South America, forests in the US and Canada and Eastern Europe, and African jungles, are all possible arable lands. But much of that land is not really suitable for crop-growing. The soil is subject to a process termed “laterization,” meaning that the organic matter quickly degrades, and the soluble minerals are depleted, leaving a largely sandy substance that is not hospitable to plant life. Also, turning jungles and forests into croplands would have a large negative impact on the atmosphere, resulting in more carbon dioxide and less oxygen. A healthy planet requires forests and jungles.

Water and arable land are the irreducible essentials to sustain human life, and they are scarcest just where the population pressure is greatest. Consider Yemen. The population of Yemen was just about 5 million in 1950. It has quintupled since then, to 25 million, and is projected to reach 100 million by the year 2100. But as of 2006, arable land in Yemen was just 0.06 hectare per capita – about an eighth of an acre. If Yemen’s population should actually hit the 100 million marker, the amount of arable land per person would be about one thirty-second of an acre – about 1400 square feet, the footprint of a single house. However, that calculation does not take into account the amount of room that 100 million people require just to live, even if they are crammed into very small quarters. So the overwhelming likelihood is that if Yemen’s population continues to grow at the current rate, lots of Yemenis will have to go elsewhere.

Speaking of Yemen, that country is at this time in a state of impending famine, with 6.8 million people (according to the UN) at risk of starvation, and another 10.2 million “in crisis.” That adds up to 17 million hungry people out of a population of 25 million – about two-thirds of the population. Similar conditions persist in Somalia, South Sudan, and Nigeria. Self-proclaimed experts insist that the underlying reasons for this are more political than otherwise – the actions taken by the Saudis against the Houthis in Yemen effectively prevent the nation from importing the food that is necessary to feed the population. But what this demonstrates is that even under stable conditions, Yemen cannot feed its population. Food has to be imported from elsewhere.

Another area where population growth has a major effect is the global economy. In fact, globalization and population growth are at odds in one particular way. Populous countries have what is known as an “absolute economic advantage” in that they have a labor surplus, and can therefore undercut less populous countries with regard to the price of many goods, especially goods that are labor intensive. More developed regions perceive this and look for ways to oppose it. Viewed from a distant perspective, globalization makes a certain amount of economic sense: goods should be made where it’s cheapest. But this can cause economic dislocations. People in developed countries lose jobs, and put pressure on government to take more protectionist positions. In the short term, this might be seen as okay: people in developed countries shift to more skilled jobs and buy cheaper stuff from the less developed world. Meanwhile, wages in the less developed parts of the world rise to levels approximating those in the better developed countries, and everyone is more prosperous.

But it doesn’t happen that way. What is happening, instead, is that the population of poorer countries continues to grow. The result is that there is a huge global labor surplus. Everybody works for less. It’s a race to the bottom, and basically Wal-Mart doesn’t care!

But aren’t birth rates declining, at least in some parts of the world?

Demographers have been counting on something they call the “demographic transition” or the “fertility shift.” It had been assumed that global population would top out at about 9 billion in the year 2050 and then level off or decline slightly. A fertility shift has been observed when the infant mortality rate declines to the point where families can trust that their children will not die in infancy. Also, in agrarian societies, children are an undeniable asset – they can be put to work doing something just about as soon as they can walk. But when children need to be fed, clothed, and, in particular, educated before they begin to contribute to the family’s support, families tend to be more careful about having lots and lots of them. For example in one Chinese province where the authorities have not enforced the one-child policy, Chinese families are still only having one child, because they perceive that the best opportunity for the child lies in receiving a good education, and one child is all they can afford. The fertility shift has already taken place in most of Europe and North America – sometimes even among groups whose religious orientation would seem to oppose the concept of family planning. However, it has not happened in many parts of the world, where population growth is still unchecked.

What will this mean? We, in North America, might think we don’t have a whole lot to worry about. We have plenty of land, and if we avoid being really stupid, we can probably manage our water resources. However, we should not turn a blind eye to the geopolitical problems that will likely come with this kind of population growth.

The refugee crisis that has literally upended the European Union is not a direct result of population pressure, but a result of the civil war in Syria. Most of the people trying to get into Europe, by whatever means, are (probably) legitimately refugees, however that term may be defined.

But here’s an example, recently in the news, although no one has linked this particular issue to population growth. We have heard about the people fleeing Libya who have landed on the Italian island of Lampedusa, with the hope of making it somehow to Europe. The EU is nervous about granting them blanket refugee status, because of the probability – or likelihood – that the current trickle of such migrants will swell to a flood.

Most of the migrants who landed on Lampedusa were not Libyans, but sub-Saharan Africans, who had previously made their way to Libya in search of some kind of decent existence. No one can possibly blame them. There were interviews with migrants who had come from cities such as Lagos, in Nigeria (a very long way from Libya), who said that they would absolutely not go back home voluntarily. Lagos, by the way, (at least according to some authorities) is the fourth most densely populated metro area in the world, where 13 million people live in an area one tenth the size of greater New York.

I do not think it is an overstatement to say that Yemen cannot possibly sustain a population of 100 million, nor Nigeria a population of 760 million, nor Africa a population of more than three and a half billion. Where will they go?

Some – a few of the more resourceful and the more fortunate – will make their way to this side of the planet. We can certainly accommodate some immigrants, but not billions. More will try to go to Europe. European nations may be willing to accommodate a few immigrants. Some commentators are quick to point to “anti-immigrant” sentiment in Europe (as well as here), frequently from the human rights perspective and within the context that immigrants – worthy, brave, hard-working, individuals – have made great contributions to every region that has received them.

However, we are not talking about moderate numbers of worthy, brave, hard-working individuals. We are talking about a human tsunami. Europe has every reason to be extremely nervous. This has contributed to, among other things, the UK’s departure from the EU.

A spokesman for the Population Council here in New York was quoted as saying, “Can we feed 10 billion people? Probably.” It may be possible to create more arable land, by clearing forests and jungles, and possibly also by irrigating deserts, but both have potentially disastrous environmental consequences. And rising sea levels, a likely result of climate change, will submerge low-lying coastal areas and result in salt-water incursions of estuaries. Futuristic schemes have been floated for building gigantic vertical farms, where food crops will be grown indoors under artificial light and nourished with chemical fertilizers. Meat substitutes, grown from non-animal substrates, are being tested. Growth enhancers of all types are already in use, such as those which speed chicken growth from the egg to the supermarket in just a few weeks. And you may have heard about the Chinese farmers that sprayed their watermelons with forchlorfenuron to accelerate their growth. They may have used a bit too much; thousands of the watermelons exploded.

Yes, we can probably somehow feed 10 billion people, although there will likely be famines from time to time. And there will be more disease, as people are crammed together with unreliable water and sanitation. And there will be violence, as the people in village A (or region A, or nation A) notice that the people in village (or region, or nation) B are just a bit better off and decide to even the score. Some economists think that that’s what happened in Rwanda – the Tutsis had more than twice as much land per capita as the Hutu, and the Hutu took the redistribution of land into their own hands. Currently, several nations with concerns about feeding their own populations have acquired huge tracts of land in Africa – South Korea, for example, has bought 1.7 million acres in Sudan, about the size of Rhode Island, to grow wheat. This will place immense demands on Nile water, on which, in turn, the downstream Egyptians depend for life itself.

The spokesman for the Population Council also said, “Will this be the end of the world? No.” No, I agree it will not be the end of the world, or the end of human life on planet Earth. But I worry that it may be the beginning of the end of civilization.

Civilization is expensive. Civilization only emerged when human beings no longer had to dedicate all their resources and all their efforts to keeping alive. Civilization is the fruit of surplus resources. What we have created, as a species, has required huge expenditures of labor and money, as well as imagination and ingenuity. Keeping 10 billion people – or more! – alive on our tiny planet is likely to require all the resources we can muster, leaving precious little for the arts and sciences.

Is this to be the destiny of our kind – to eke out a bare existence on a crammed planet? I don’t believe that anyone wants this to be our fate. I am enough of an optimist to believe that at some point in the coming years, more and more of us will realize that our population trends have got to do a U-turn. This means family planning. An encouraging statement from the UN population division points out that when women in some of the poorest countries are offered information and voluntary access to birth control, they have chosen to have fewer children. However, global aid to pay for birth control has not increased in the past decade, and we in the US are not doing our part.

I realize that a position such as the one I have outlined here is sometimes characterized as being racist and xenophobic. Some would say that it is based on fears that a non-white population will overwhelm people of European descent. I point out that those who will suffer the most are the African and Asian populations. The Americas will likely accommodate some immigration, but its distance from the most overpopulated parts of the world will insulate it. Europe will try to fend off immigration by whatever means. The developed world – Europe and the Western Hemisphere – will fare much, much better than the rest of the planet.

What we and the rest of the developed world cannot insulate ourselves from is the effects of population growth on the underlying health of our planet. Currently, there are about 620 million people in Asia who do not have electricity, more than 300 million in India alone. And 600 million more in Africa, including 97% of the population of South Sudan, 85% in Congo and Madagascar, 81% in Kenya, and so on. What people in India want more than anything else seems to be air conditioning. This is not surprising, given the increasing temperatures that have been recorded in those parts. A high of 123⁰ F was recently recorded in New Delhi. Humans cannot long survive at those temperatures. So, regardless of the best intentions, it seems likely that electricity will be generated by whatever means and at whatever cost to the environment.

I ask myself why this matters so much to me. It is extremely unlikely that our little patch of land will ever be taken over to raise food for 32 or 64 unfortunates. It is also unlikely that our town, or the tiny island where we vacation, or even New York City, where we sing and go to concerts and museums, or indeed, that anywhere that we are likely to go, is going to become unsustainably overpopulated any time soon. So why do I care? Because we need to live on this island earth for a very, very long time, and we need to be able to go on doing the things we do best. Our mere survival as a species, to my view, counts for very little. What counts is what we have created: Civilization. We can only continue to do that if survival is not our sole objective.

So I ask you, my friends, to keep this in mind. People everywhere surely want what is best for their own descendants. Given the means and the opportunity, most people will behave in such a way as to improve their chances. Most people would welcome family planning assistance. We should press our leaders to help make it available. Not less than everything may depend on it

* * * * * * *
I recognize that this piece is something of a departure for Doc Gumshoe, and I will be grateful for any and all comments, including from readers who strenuously disagree, for whatever reason. I will also acknowledge that this piece, more than any I have sent your way, relies on a huge amount of data that I have no conceivable way of verifying. For example, with regard to the figures I have cited regarding the population density of various countries and cities, I have picked what on first inspection appeared to be the most reliable. But there are wide disparities, sometimes depending on the definition of a city: just what is a city, and where does it start and leave off? Those of us living in the so-called Greater New York area are accustomed to thinking that New York consists of the five boroughs, but also recognizing that Greater New York takes in parts of New Jersey (including Newark) and parts of Connecticut. But I have read that the Chinese have plans to enlarge Greater Beijing so that it attains a population of well over 100 million.

However, no matter how we slice and dice, the overall picture, I solemnly promise, is true. Our planet is getting overcrowded, and the effects – for us, mostly long-term, might be genuinely dire. So I thank you for reading my screed and thinking about it.

Doc Gumshoe will be back before long with a piece reporting recent developments on the medical front that I hope will be of interest to you. Best to all, Michael Jorrin (aka Doc Gumshoe)