Forecast | Population growth vs. control: Future of human population P4

Some say the world population is set to explode, leading to unprecedented levels of starvation and widespread instability. Others say the world population is set to implode, leading to an era of permanent economic recession. Amazingly, both viewpoints are correct when it comes to how our population will grow, but neither tell the whole story.

Within a few paragraphs, you're about to get caught up with about 12,000 years of human population history. We'll then use that history to explore how our future population will play out. Let's get right into it.

History of world population in a nutshell

Simply put, the world population is the total number of humans currently living on the third rock from the sun. For much of human history, the human population’s overarching trend was to grow gradually, from only a few million in 10,000 BC to about one billion by 1800 CE. But shortly thereafter, something revolutionary happened, the Industrial Revolution to be exact.

The steam engine led to the first train and steamship that not only made transportation faster, it shrunk the world by providing those once confined to their townships easier access to the rest of the world. Factories could become mechanized for the first time. Telegraphs permitted the transmission of information across nations and borders.

All-in-all, between roughly 1760 to 1840, the Industrial Revolution produced a sea change in productivity that increased the human carrying capacity (the number of people that can be supported) of Great Britain. And through the expansion of the British and European empires over the following century, the advantages of this revolution spread to all corners of the New and Old worlds.


By 1870, this increased, global human carrying capacity led to a world population of about 1.5 billion. This was an increase of half a billion in a single century since the start of the Industrial Revolution—a growth spurt larger than the last few millennia that preceded it. But as we're well aware, the party didn't stop there.

The Second Industrial Revolution happened between 1870 and 1914, further improving living standards through inventions such as electricity, the automobile, and the telephone. This period also added another half billion people, matching the growth spurt of the first Industrial Revolution in half the time.

Then shortly after the two World Wars, two broad technological movements occurred that supercharged our population explosion. 

First, the widespread use of petroleum and petroleum products essentially powered the modern lifestyle we’re now accustomed to. Our food, our medicines, our consumer products, our cars, and everything in between, has either been powered by or entirely produced using oil. The use of petroleum provided humanity with cheap and abundant energy that it could use to produce more of everything cheaper than ever thought possible.

Second, especially important in developing countries, the Green Revolution happened between the 1930s to 60s. This revolution involved innovative research and technologies that modernized agriculture to the standards we enjoy today. Between better seeds, irrigation, farm management, synthetic fertilizers and pesticides (again, made from petroleum), the Green Revolution saved over a billion people from starvation.

Together, these two movements improved global living conditions, wealth, and longevity. As a result, since 1960, the world's population rose from about four billion people to 7.4 billion by 2016.

World population set to explode … again

A few years ago, demographers working for the UN estimated that the world’s population would top out at nine billion people by 2040 and then gradually decline throughout the rest of the century to just over eight billion people. This forecast is no longer accurate.

In 2015, the United Nations’ Department of Economic and Social Affairs released an update to their forecast that saw the world population peaking at 11 billion people by 2100. And that's the median forecast! 

The chart above, from the Scientific American, shows how this massive correction is due to larger than expected growth in the African continent. Earlier forecasts predicted fertility rates would drop noticeably, a trend that hasn't materialized thus far. High levels of poverty,

lowering infant mortality rates, longer life expectancies, and a larger than average rural population have all contributed to this higher fertility rate.

Population control: Responsible or alarmist?

Anytime the phrase ‘population control' is thrown around, you'll invariably hear the name, Thomas Robert Malthus, in the same breath. That's because, in 1798, this quotable economist argued in a seminal paper that, “Population, when unchecked, increases in a geometrical ratio. Subsistence increases only in an arithmetical ratio."  In other words, the population grows faster than the world’s ability to feed it. 

This train of thinking evolved into a pessimistic view of how much we consume as a society and the upper limits of how much total human consumption the Earth can sustain. For many modern Malthusians, the belief is that should all seven billion people living today (2016) attain First World consumption levels—a life that includes our SUVs, our high protein diets, our excess use of electricity and water, etc.—the Earth won't have near enough resources and land to meet everyone's needs, let alone a population of 11 billion. 

In all, Malthusian thinkers believe in aggressively decreasing population growth and then stabilizing world population at a number that would make it possible for all of humanity to share in a high standard of living. By keeping the population low, we can achieve high consumption lifestyles without adversely impacting the environment or impoverishing others. To better appreciate this viewpoint, consider the following scenarios.

World population vs. climate change and food production

Explored more eloquently in our Future of Climate Change series, the more people there are in the world, the more people are consuming the Earth’s resources to go about their daily lives. And as the number of middle class and affluent people increases (as a percentage of this growing population), so too will the total level of consumption grow at exponential rates. This means ever greater amounts of food, water, minerals, and energy extracted from the Earth, whose carbon emissions will pollute our environment. 

As explored fully in our Future of Food series, a worrying example of this population vs. climate interplay is playing out within our agriculture sector.

For every one-degree rise in climate warming, the total amount of evaporation will rise by about 15 percent. This will have a negative impact on the amount of rainfall in most farming regions, as well as on water levels of rivers and freshwater reservoirs across the world.

This will impact global farming harvests as modern farming tends to rely on relatively few plant varieties to grow at an industrial scale—domesticated crops produced either through thousands of years of manual breeding or dozens of years of genetic manipulation. Problem is most crops can only grow in specific climates where the temperature is just Goldilocks right. This is why climate change is so dangerous: it will push many of these domestic crops outside their preferred growing environments, raising the risk of massive crop failures globally.

For example, studies run by the University of Reading found that lowland indica and upland japonica, two of the most widely grown varieties of rice, were highly vulnerable to higher temperatures. Specifically, if temperatures exceeded 35 degrees Celsius during their flowering stage, the plants would become sterile, offering little to no grains. Many tropical and Asian countries where rice is the main staple food already lie on the very edge of this Goldilocks temperature zone, so any further warming could mean disaster.

Now consider that a large percentage of the grain we grow is used to produce meat. For example, it takes 13 pounds (5.6 kilos) of grain and 2,500 gallons (9463 liters) of water to produce a single pound of beef. The reality is that traditional sources of meat, like fish and livestock, are incredibly inefficient sources of protein when compared to protein derived from plants.

Sadly, the taste for meat isn't going away anytime soon. The majority of those who live in the developed world value meat as a part of their daily diets, while the majority of those in the developing world share those values and aspire to increase their meat intake the higher up the economic ladder they climb.

As the world population grows, and as those in developing countries become more affluent, global demand for meat will skyrocket, exactly as climate change is shrinking the amount of land available to farm grains and raise cattle. Oh, and there’s also the whole issue of all the agriculture-fueled deforestation and methane from livestock that together contributes up to 40 percent of global greenhouse gas emissions.

Again, food production is only ONE example of how human population growth is driving consumption to unsustainable levels.

Population control in action

Given all these well-founded concerns around unbridled population growth, there may be some dark souls out there pining for a new Black Death or zombie invasion to thin out the human herd. Luckily, population control need not depend on disease or war; instead, governments around the world have and are actively practicing various methods of ethical (sometimes) population control. These methods range from using coercion to re-engineering social norms. 

Starting on the coercive side of the spectrum, China's one-child policy, introduced in 1978 and recently phased out in 2015, actively discouraged couples from having more than one child. Violators of this policy were subject to harsh fines, and some were allegedly forced into abortions and sterilization procedures.

Meanwhile, the same year China ended its one-child policy, Myanmar passed the Population Control Health Care Bill that enforced a softer form of enforced population control. Here, couples looking to have multiple children must space each birth three years apart.

In India, population control is facilitated through a mild form of institutionalized discrimination. For example, only those with two children or less may run for elections in local government. Government employees are offered certain child care benefits for up to two children. And for the general population, India has actively promoted family planning since 1951, even going so far as to offer women incentives to undergo consensual sterilization. 

Finally, in Iran, a surprisingly forward-thinking family planning program was enacted nationally between 1980 to 2010. This program promoted smaller family sizes in the media and required mandatory contraceptive courses prior to couples obtaining a marriage license. 

The downside of the more coercive population control programs is that while they are effective in stemming population growth, they can also lead to gender imbalances in the population. For example, in China where boys are regularly preferred over girls for cultural and economic reasons, a study found that in 2012, 112 boys were born for every 100 girls. This may not sound like much, but by 2020, males in their prime marrying years will outnumber females by over 30 million.

But isn't it true that the world population is shrinking?

It may feel counterintuitive, but while the overall human population is on course to hit the nine to 11 billion mark, the population growth rate is actually in a freefall in much of the world. Throughout the Americas, most of Europe, Russia, parts of Asia (especially Japan), and Australia, the birthrate is struggling to stay above 2.1 births per woman (the rate needed at least maintain population levels).

This growth rate slow down is irreversible, and there are a variety of reasons why it's come about. These include:

Access to family planning services. In those countries where contraceptives are widespread, family planning education is promoted, and safe abortion services accessible, women are less likely to pursue family sizes of more than two children. All governments in the world offer one or more of these services to a certain extent, but birth rates continue to remain far higher than the global norm in those countries and states where they are lacking. 

Gender equality. Studies have shown when women gain access to education and job opportunities, they are better enabled to make more informed decisions about how they plan their family size.

Falling infant mortality. Historically, one reason that spurred larger than average childbirth rates was the high infant mortality rates that saw scores of children die before their fourth birthday due to disease and malnutrition. But since the 1960s, the world has seen steady improvements to reproductive healthcare that have made pregnancies safer both for the mother and child. And with fewer average child deaths, fewer children will be born to replace those that were once expected to die early. 

Increasing urbanization. As of 2016, over half the world's population live in cities. By 2050, 70 percent of the world will live in cities, and closer to 90 percent in North America and Europe. This trend will have an outsized effect on fertility rates.

In rural regions, especially where much of the population is involved with agricultural work, children are a productive asset who can be put to work for the benefit of the family. In cities, knowledge-intensive services and trades are the dominant forms of work, which children are ill-suited for. This means children in urban environments become a financial liability to parents who must pay for their care and education until adulthood (and often longer). This increased cost of child-rearing creates a growing financial disincentive for parents who are thinking of raising large families.

New contraceptives. By 2020, new forms of contraceptives will hit global markets that will give couples even more options to control their fertility. This includes an implantable, remote-controlled microchip contraceptive that can last up to 16 years. This also includes the first male contraceptive pill.

Internet access and the media. Of the 7.4 billion people in the world (2016), about 4.4 billion still don’t have access to the Internet. But thanks to a number of initiatives explained in our Future of the Internet series, the entire globe will come online by the mid-2020s. This access to the web, and the Western media available through it, will expose people across the developing world to alternative lifestyle options, as well as access to reproductive health information. This will have a subtle downward effect on population growth rates globally.

Gen X and Millennial takeover. Given what you've read thus far in the previous chapters of this series, you now know that the Gen Xers and Millennials due to take over world governments by the end of the 2020s are considerably more socially liberal than their predecessors. This new generation will actively promote forward thinking family planning programs around the world. This will add yet another downward anchor against global fertility rates.

Economics of a falling population

Governments now presiding over a shrinking population are actively trying to boost their domestic fertility rates both through tax or grant incentives and through increased immigration. Unfortunately, neither approach will significantly break this downward trend and this has economists worried.

Historically, birth and death rates shaped the general population to look like a pyramid, as depicted in the image below from This meant that there was always more young people being born (bottom of the pyramid) to replace the older generations dying out (top of the pyramid). 

But as people around the world are living longer and fertility rates are shrinking, this classic pyramid shape is transforming into a column. In fact, by 2060, the Americas, Europe, most of Asia and Australia will see at least 40-50 elderly people (65 years or older) for every 100 working age people.

This trend has serious consequences for those industrialized nations involved in the elaborate and institutionalized Ponzi scheme called Social Security. Without enough young people born to financially support the older generation into their ever-extending old age, Social Security programs the world over will collapse.

In the near term (2025-2040), Social Security costs will spread out over a shrinking number of taxpayers, eventually leading to increased taxes and reduced spending/consumption by the younger generations—both represent downward pressures on the global economy. That said, the future isn’t as grim as these economic storm clouds suggest. 

Population growth or population decline, it doesn't matter

Going forward, whether you read nerve-wracking editorials from economists warning about the shrinking population or from Malthusian demographers warning about the rising population, know that in the grand scheme of things it doesn’t matter!

Assuming the world population grows to 11 billion, for sure we'll experience some difficulty providing a comfortable lifestyle for all. Yet, in time, just as we did in during the 1870s and again in the 1930-60s, humanity will develop innovative solutions to increase the Earth's human carrying capacity. This will involve massive leaps forward in how we manage climate change (explored in our Future of Climate Change series), how we produce food (explored in our Future of Food series), how we generate electricity (explored in our Future of Energy series), even how we transport people and goods (explored in our Future of Transportation series). 

To the Malthusians reading this, remember: Hunger isn’t caused by there being too many mouths to feed, it’s caused by society not effectively applying science and technology to increase the amount and decrease the cost of the food we produce. This applies to all other factors that affect human survival.

To everyone else reading this, rest assured, over the next half-century humanity will enter into an unprecedented era of abundance where everyone can share in a high standard of living. 

Meanwhile, if the world population should shrink faster than expected, again, this abundant era will protect us against an imploding economic system. As explored (in detail) in our Future of Work series, increasingly intelligent and capable computers and machines will automate most of our tasks and jobs. In time, this will lead to unprecedented productivity levels that will provide for all of our material wants, while allowing us to lead ever greater lives of leisure.


By this point, you should have a solid handle on the future of the human population, but to truly understand where we're going, you'll also need to understand both the future of old age and the future of death. We cover both in the remaining chapters of this series. See you there.

Future of human population series

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February 26, 2021. Last updated February 26, 2019.
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