Peak Child: When, and what does it mean?

Synopsis: Don’t Panic, for most people, this is good news.

It’s now 10 years since I began researching and writing about how peak child was approaching, and as around 8 years have passed since this was first published using the label “peak child” as first coined by Hans Rosling and the Gapminder foundation, now in 2024 it is time for a new edition better referencing the increased amount supporting population related content on this site enables a new edition.

There are at least 4 not necessarily mutually exclusive reactions to hearing the planet is reaching peak child:

1. People ask: what exactly is “peak child” and what is the significance?
2. Others feel this ‘peak’ can’t be real, because population growth is still a threat and “Growth must stop NOW!”
3. Some people fear it is peak child that is a threat and are concerned falling fertility rates could be a threat to the survival of our species.
4. And there are cries of “Oh no, ending population growth will be economic disaster! If this is true, then customer bases will stop growing, ending our perpetual exponential economic growth”.

This section looks gives and overview response to each reaction, with a link to a more dedicated section on this page for each, with links to more content and even further background to the material presented here.

First for the definition of peak child, what is behind it and the implications. The definition of peak child as given in more detail below is that peak child is reached near the end of a period of population growth when birthrate falls sufficiently that the number of children is no longer increasing from year to year. Population growth and a falling birthrate plays a key role in the story of how humanity arrived at where is has in the early 21st century, having transformed for the better the experience parenthood for humans through the reduction of childhood deaths:

The chances that a newborn survives childhood have increased from 50% to 96% globally [from 1750 to 2023]. This article asks how we know about the mortality of children in the past and what we can learn from it for our future.

by Max Roser April 11, 2023: Our world in data “Child mortality in the past”.

Addressing child mortality means a vast reduction in the tragedy of the deaths of children with the added benefit of being the main driver of increased life expectancy, but the potential downside has been a population explosion even despite birthrates falling from the time the population surge began. Opinions vary on whether this population explosion we had was beneficial or problematic, but without a falling birthrate that limited the population growth it could have been catastrophic:

If the historical average birthrate of 7 births per woman had continued throughout the entire 20th century and beyond to 2022, without some new source of deaths the global population would in 2022 be at over 25 billion.

Just imagine, every city with 3 times the population and producing 3x the emissions and needing 3x the global food production. Just finding 3x the water for many cities would become impossible.

In reality, without falling birthrates society could have collapsed decades earlier than 2022 as failing to feed and house the population surge would have ultimately proved impossible, with deaths in the billions until the population fell to close to current levels, which without the fall in birthrates would result in a likely return to the life expectancy of the year 1900.

What if birthrates did not decline at all as child mortality was reduced?

Population growth is determined by the difference between the numbers of births and number of deaths, and although birthrates did progressively fall over the same period, not quite as fast mortality rates fell, so we still had a population explosion, but at a reduced level that we have been able to manage, albeit at the expense of borrowing from the future by exceeding sustainability.

This brings us to the picture at the time of the 2024 update. Peak child has been reached, which means peak human population is now expected in the near future.

While people have in the past somewhat justifiably panicked about population growth putting our survival at risk, now it seems there may be more people who instead fear falling birthrates, but this brings us first to concerns of those who remain concerned our population will be too high.

On one hand, for those in the group #2: “It can’t be real, population growth is still a threat”, then there is good news that the evidence that ‘peak child’ is now real is quite clear but the bad news in that not all challenges of population growth are yet solved, and population may grow locally in developed cities and countries even if it ends globally. It seems very possible that climate change will not be taken sufficiently seriously unless manages to reduce the carrying capacity of the planet, pushing humanity into overpopulation not because of rising numbers, but due to reduced ability of the planet to support people living in the current locations and in the current numbers. Plus, humanity not far from the trigger for a second, even more challenging population explosion.

For those included in group #3 with concerns “could the peak child and falling birthrates be a threat to our survival?”, be reassured that despite the clickbait and confirmation bias of those from group 4 with an economic interest in population growth, if humans really needed to maximise the number of children to survive, then the genes which increase the incidence of twins would have begun to dominate many thousands of years ago.

A common source of confusion is to confuse the ideal number of offspring for just one individual with the ideal number for the entire species, and these two numbers are not the same. While for one single individual, having more offspring that survive to become adults and themselves reproduce helps their genes succeed, too many offspring for the species will mean competition for insufficient resources will produce generations undernourished and vulnerable endangering the species. Overall, for the species, the goal is neither too few nor too many, but the right number of offspring for the conditions.

Environment Sensitive Reproduction & Population: Survival is about the right number of kids.

Rather than being a problem, the fall in birthrates has so far been exactly what we have needed to avoid billions of deaths and a possible threat to our very survival. Yes, higher birthrates could provide more consumers and increase corporate profits and provide politicians with an increased powerbase, but at least so far, they have been not a threat but our saviour. There is a paper here on the cause of falling birthrates, but as discussed below, the reality is the return of a threat of overpopulation is almost certainly what we will next face.

Which brings us to group #4, and peak child posing the threat of an economic disaster because companies may no longer be able to experience an increased consumer base through population growth alone. Without population growth as a simple way to grow their business, companies would need to either grow their market share or get consumers to increase their total spending, and an increase in total spending requires countries solving the pesky problem of increasing per capita consumer wealth rather than just growing the economy without worrying about distribution of wealth. As not all companies can grow market share, how would stock market indexes keep increasing without population growth?

Yes, it turns out that even though peak child sounds like an economic threat to big business, and an end to population growth, economies don’t actually depend on birthrates for population growth and the threat to big business is of the myth of prosperity through population growth being exposed.

As an example, consider how despite a birthrate of only 1.6, way below the 2.2 required for even population stability, in 2023 managed economic growth through population growth to avoid a recession through population growth alone even when living standards per person fell.

The economy has now grown for seven consecutive quarters. However, it isn’t managing to keep pace with population growth. In per capita terms, real GDP fell 0.3 per cent quarter-on-quarter, repeating the March quarter’s outcome. That means that Australia has fallen into a technical ‘per capita recession’.

Australia: Headline growth beats expectations but goes backwards per capita

In all developed economies like Australia, USA, Canada etc , a survey of national births per women will universally reveal that a national birthrate has been well below the 2.2 level require for population stability for decades and there has long been a reliance on immigration for providing any population growth or even population stability. It seems very possible that when the people of the nation seem to be deciding either consciously or subconsciously that the environment calls for less children than the number to even maintain the population, government policies that ensure a rising population could create resentment. The actual threat to the economy is that the resentment causes governments to look for a real solution that would reduce total immigration rather than channelling resentment against those immigrants who generally have least real impact: refugees and/or “illegal immigrants”.

Overall, even those fearing a loss of growth for big business have little to fear, as disruption from climate, disruption to industry to address climate change, AI and robots, and even the future second population explosion will change the fundamentals of the economy long before voters lose interest in “border protection” and question policies or countries used as “people farms” stop providing a supply of migrants for population growth.

Immigration tops voter issues

CNN polling director Jennifer Agiesta notes there’s been a sharp rise in the share of Americans who call immigration the most important problem facing the country, and it now tops every other individual issue named, according to polling this month from Gallup.

The shift in the new survey comes largely among Republicans: 57% of Republicans now call immigration the top problem facing the country, up from 37% who said so in January, she adds. The share of independents (22% now vs. 16% in January) naming immigration as the top problem has risen by a smaller amount, while among Democrats it has largely held steady (10% now vs. 9% in January).

Problems related to the government or poor leadership rank second behind immigration, with 20% naming those, 12% naming the economy in general and 11% the high cost of living or inflation.

CNN Feb 2024: A new Biden is on display in public

What is ‘Peak Child’?

Definition.

Hans Rosling famously coined the term ‘peak child’ for the moment in global demographic history at which the number of children in the world stops increasing.

“Our world in data“.

Peak Child is when the number of children has reached a maximum number, and from that point the number of children will either remain constant, or even decrease. Therefore “peak child” is a peak or plateau in growth of the population of children.

Since the entire population begins as children, peak population will follow within the length of one lifetime unless there is return to growth in the population of children.

This means ‘Peak Child’ is the predictor of peak population following a period of population growth, but could occur up to one full lifetime before peak population and will occur even while the total population is still growing. Realising we were headed to peak child was a key step in the path to my current understanding of population.

It is important to recognise “peak child” reflects population growth, and population growth does simply reflect fertility rates or “births per woman”, and the changes in population growth reflect a complex interaction between child mortality rates and birth rates.

The red line on the graph to the right shows population growth rates from 1750 to 2015 plus future projections, the peak population growth of 1950 occurred births per 1,000 people were at around 15 and much lower than in 1700 when population growth was lowest but births per 1,000 highest at 35.

The transition to peak child would normally occur, as is happening currently, as a period of global population growth is less than one lifetime from its end.

Peak Child Vs Peak Population.

While a national population can keep growing through immigration despite low birthrates, given the absence of immigrants to the Earth from other planets, having globally reached “peak child” it takes something radical to prevent global “peak population” from soon following.

Peak child can occur anywhere up to one lifetime (between 0 and approximately 80 years) prior to peak population depending on the rate at which birthrates fall.

My estimate is peak human population before 2050, at least until the likely at least 100 years before the next population explosion. Note there are others including UN projections for population growth continuing at a very gradual pace for much longer, although these same sources were already wrong on when their projection for peak child largely because released data is impacted by politics.

Significance: What does peak child really mean for society?

The day-to-day impact is increased pressure on national borders and rising discontent increasing support for populist politicians, particularly those questioning immigration and border issues.

This because peak child means people worldwide are experiencing feelings that:

• Things are already too crowded.
• The environment will not support further increased population.
• Humans are not managing to live sustainably.
• There is a lack of confidence in the future.

Part of the reason developed nations have these symptoms already is that most developed nations have already for decades had the birthrates that would lead to peak child but have also had immigration that has kept the population growing despite low domestic birthrates.

Whilst all nations with low birthrates quickly ending immigration is impossible, and ending refugee intake without solving the problems would be unconscionable, not even having plan to end population growth on a planet where population growth is ending is a recipe for discontent.

While there is no suggestion wealthy nations intent to keep people in less wealthy nations oppressed so they can act as “people farms” with their most educated citizens easily lured to migrate elsewhere, that does not mean wealthy nations do no use this to boost their economies. The overall effect is a drain on population within those less wealthy nations that would logically encourage higher birthrates to maintain their population, and the pressure of population growth on the wealthier countries creating even more reason for citizens to keep their birthrates lower.

What is the significance for nature of humans reaching peak child?

We live on a planet hosting a finite, but every so slowly decreasing since “peak life” approximately 500 million years ago. This makes life a zero-sum game where an increase in the population of any one species means a decline in others. For the first 300,000 years of humans on Earth, very few other species were impacted by any population gains by humans, but by the time humans reached 2 billion in around 1923 the impact was significant, and while some felt by the time population reached 4 billion in around 1972 the impact was significant that we entered the Anthropocene era, and having reached 8 billion by 2021, the impact of any further increase in human population is now dramatic. It does feel like one more population doubling of humans. if even possible, would leave few other species still sharing the planet.

For nature, it is hard to see how human population growth slowing can be other than a necessity.

The Data: Are We Really There Yet? Really??

2014: Hans Rosling Declares, yes we basically have peak child.

Hans Rosling declared we are already at peak child globally.

Hans Rosling was a great statistician, a wonderful humanitarian, but perhaps also an optimist, maybe he was technically a few years early. Still, conceptually, he was correct when he stated the world is at peak child in 2014, although ‘births per woman’ was still at 2.5. Now, in 2019 it still marginally above 2.4, and the magic number, thought to be ‘between 2.4 and 2.2’, will be confirmed at the earliest by 2020, and at the latest by 2034. So for ‘peak child’ to have been already reached by 2014, it definitely could not have included all children under 18. Overall, you could argue that Hans was a little early, but not very early. We were basically at peak child at the time of his prediction, if not technically yet having already passed peak child.

2021 Update & Analysis: Peak Child From 2017 Confirmed By Birth Records.

In fact clear data confirmed fully reaching ‘peak child’ just a little earlier than I expected.

The graph to the right, which is available in interactive form at ourworldindata, uses UN data and projections. While the projections can be disputed, the data up to the current time is the most accurate available, and shows a gradual decline in births since 2017.

Two important points when analysing the data:

• Both ‘births per woman’, which is a lifetime calculation, and data for actual births should be considered together, as factors can cause a delay, or acceleration in families having children, without a change in the total number of children those families will have.
• While ‘peak child’ peak child occurs when children are born in the same numbers as their parents, who were born 20-30 years earlier, deaths for the same year are biased towards the far smaller number of those born around 80 years earlier, when the population was smaller.

It Is Not Happening Here!: Global Distribution Of Peak Child.

While globally the world is at peak child, this is an aggregate. Births rates for nations range from 6.8 to 0.8, and even then vary within nations, and then there is migration, which relocates the impact of birth rates.

The global trend is a reduction in birth rates towards sustainability, and even below sustainability, but not every location on the globe is at the the same point on the reduction, and not every location need to heading towards the same outcome.

Looking at the global data, the locations with highest birth-rates still have the highest child mortality, as well as other problems which will hopefully be solved. As a general pattern, it is better to be living in a country with berth-rates per woman below 2.3, than one with birth rates above 2.3, but birth rates still vary somewhat within countries.

Generally, counties where peak child is not their current national experience, it is their future, and the already feel the impact of peak child globally.

But as we live in a global society with a global economy, and will experience changes socially and economically as the impact of returning to ‘peak child’ after around three very formative centuries when it seemed to become normal for each generation to be larger than the one before, even if your own country is not yet at peak child, the impact of reaching peak child globally still impacts everyone.

OK: So Why do we still have Population Growth?

The Long Lag Between ‘Peak Child’ and ‘Peak Population’.

Some question, why are we not stopping population growth immediately? How can we be at peak child and the population still grows?

The population still continues to grow following for many years after peak child, as numbers of older age groups still increase until the first group of ‘peak children’ age into ‘peak adults’, and eventually ‘peak retirees’. Hans Rosling again has presents an explanation, as does this page on the population pipeline lag. I have now found others answering this same question.

In summary, there is a delay between ‘peak child’ and peak population, but once peak child is reached, the only thing that can stop peak population coming soon after is a reversal of trends in children per woman.

Can The ‘Lag’ Result In Another 3 Billion People?

At the time of writing (May, 2019) the world population is over 7 billion. If we remain at the current ‘peak child’, which would be following the projections of Hans Rosling and those used by the UN as charted by ourwordindata, then population will reach almost 11 billion in future. On current trends, it is inevitable population numbers will peak, but as discussed later below, there is not universal agreement on at what number or even if current trends will continue.

Estimates vary between people pushing for a return to ever increasing numbers and increased birth-rates, and others who believe the trend of falling birth-rates does not magically stop at the current point, but will continue further.

Obviously, those wanting increased birth-rates believe population can keep growing, perhaps forever, while those who believe birth-rates will fall further anticipate potentially less than 10 billion people as a maximum, and a correction in global population for some time following that peak population.

In nature, while organisms experience periods of population growth as they displace other living things, no population ever continues growing indefinitely and instead finds a normal population. Perhaps we are beyond nature?

In summary, other outcomes are possible, but if everything remains at the current rate of births, then expect another 3 billion people before population stabilises.

2022 Update: China, the most populous nation, has passed peak child.

This update is detailed in its own exploration.

How & Why did we get back here: global fall in births / woman.

The Fall In Birth Rates Result In A Return To Normal.

Survival Rates Have Increased.

Until the last few centuries, far fewer children survived to become adults and have own children, so far more ‘births per woman’ were required to maintain the species.

But then medicine advanced, and infant mortality dramatically improved, triggering a population explosion.

The end result of reduced child mortality is that less births are required for the same rate of population growth. Families have less births, but a similar number of children who grow to have their own children to the normal prior to around 1700.

Births Per Women Now Below 2.4, From Over 5.0 in 1960.

This return to ‘peak child’ is the culmination of over 60 years of a significant fall in the rate of ‘births per woman‘. Having already fallen from historically over 6 to a global average of around 5 by 1960, the rate has since fallen far more dramatically to just over 2.3 today. Hans Rosling was the expert on the statistics of how we got to here, but although he also has theories on why the population has moved to a new stability, these, as opposed to his statistics, are conjecture. Having explored many theories, as discussed in “How the Explosion Came To An End“, the only theory I have found that explains the universal fall across societies and cultures I found found is the theory of ‘optimum population‘: all highly evolved species will normally naturally reproduce at close to the rate for a stable population.

Return To Peak Child Is A Return To Normality.

After a few centuries of a population explosion, for us it feels like rapid population growth is normal, and ‘peak child’ is something new. All our recent history is population growth. But those last 200 years are at odds with the entire 300,000 year history of humans. Looking at the data reveals it is population growth that is unusual, and experiencing peak child is normal.

Throughout human history, for all but the period for 1650-2000 CE, humans reproduced at rate between slightly below, and just slightly above, the rate required for a stable population, with population growth below 0.05%. In Hans Rosling’s words ‘they died in balance with nature‘. This population stability required reproduction in quite exact balance with the number of children who would survive. At least until the 17th century when, as medicine and survival improved requiring a rapid fall in birth rates in order compensate, growth began to surge. Humans have adjusted our birth-rate in order to compensate, but the balance is imperfect, in part because it takes at least one generation to make the adjustment. The recent population explosion resulted when infant mortality rates fell too quickly for birth rates to be able adjust. It seems we have now adjusted to a ‘new normal’ where very few children die before adulthood, by having between 2.2 and 2.4 children, which is well down from the historical average of 6.

So Why Have Birth-rates Fallen From 20th Century Average?

Note, some of these proposals are also limited, in that while they provide suggestions for why birth-rates fell since, for example the 1960s, but provide no explanation of why birth rates prior to1700s were “in balance with nature“.

If someone had successfully predicted the fall in birth-rates throughout the 20th century prior to it happening, then we could have confidence their hypothesis has been tested. Instead, we have only proposals to explain the data after it happened.

I have a full page dedicated to examining the alternative explanations of why birth rates fell, but here is a short summary.

Option 1: Society Changes Including, The Pill, Educations of Women, Family Planning, etc

A popular approach is to look for factors in society that changed in correlation with the fall in birth-rates. The problem with this approach, is that it relies upon coincidence. That the adjustment to a birth-rate that again results in population now we have lower infant mortality rates, just happened to occur at the right time.

There is the suggestion that women were always having more babies than educated women would choose to have, if they had access to birth control. This means that if we educated women and improved birth control centuries ago, before we reduced infant mortality, the human population would have almost died out, as women would have had only 2 babies, even when 2 of 3 babies died before having heir own families. Really?

Option 2: Optimal Population Mechanisms Resulting In Birth-Rates Adjusting Needs.

The big picture of human population is remarkable stability, and ‘peak child’ is the return to population stability. If population stability, as projected by UN and discussed by Hans Rosling is the natural balance, then births may remain at the current level for many decades to come.

The optimal population hypothesis is that there are mechanisms that result in rates of reproduction adjusting within a possible range to suit circumstances. This is discussed in full in another page, but there is clear evidence that, either as a result of conscious decisions, or just biology, birth-rate adjust in nature to fit environmental circumstances.

Under this view, as modelled by Deutsche bank and other think tanks, is that nature seeks a to return to a ‘optimal population‘, which achieves sustainability, and unless we interfere with nature, birth-rates may fall further still yet, if we do not first achieve sustainability.

Consequences: Don’t Panic, We Have Been Here Before.

After So Many Generations Of Growth, Stability Is Unfamiliar.

The world has been in a population explosion since around 1650, which means for almost 10 generations all we have experienced is rapid population growth. This explosion was driven by an average of 2.4 just children per couple surviving to have their own children, which was a huge step up from the 2.033 children per couple of the previous 6,500 years. Even that previous period, which still did surprisingly result in gradual population growth, was above the longer-term average of 2.002 children per couple surviving to have their own children, despite couples having far more children than that.

Peak child is a key indicator of population growth trends and understanding the concept of ‘Peak Child’ is critical to the journey to understanding what is happening with population. While it seems hard to believe the world has reached peak child, it seems equally hard to believe this target has been reached without already ending population growth or yet achieving peak population, which may not occur until 2055. The implications of peak child, in a world so adjusted to population growth, will create turmoil for future investments and economics, whilst bringing some relief for those fearing global warming, extinctions, and reduction in income and rising inequality, that results from high population growth. While there are adjustments required, only billionaires looking to increase their wealth as the wealth of the average person falls, have anything to fear from the possibilities of peak population.

We Have Been Here Before, and will be again.

Yes, we have had over 200 years of a population explosion, where the concept of peak child has seemed unimaginable, but for almost all of human history humanity has actually existed in a state of ‘peak child’, or so close to ‘peak child’ that growth would not be noticeable at the time.

Throughout most of history, population growth has been so gradual that the number of children year after year would show no noticeable change, even over a century. Yet even the period of history, is curiously one of higher population growth than prehistoric averages, and higher than with other species.

Population growth at the rate of the recent explosion would carpet the entire surface of the Earth with humans within just a few thousand years if it continued, and as humans have existed for at least 300,000 years, so for almost all of those 300,000 years, humans must have existed in a state of ‘peak child’. Prior to reducing infant mortality, there were more children per family, but there we so many child deaths in previous times, that population was relatively stable until the industrial revolution, even with bigger families. It has never been a problem existing in a state of peak child previously, or we would be extinct, as we would have long ago exhausted all resources. Perhaps we will now remain at ‘peak child’ until another population explosion that will happen if we manage to spread beyond one planet.

Consequences: An Economic Death Spiral?

One of the frequently pushed ‘pro population growth‘ messages is that without population growth, economic doom awaits. This deceptive message reflects that many economic indicators are tuned towards total tax revenues, the minority that does benefit from population growth and only the largest of companies. Yet countries with low population growth consistently outperform those with high population growth in terms of economic prosperity of their citizens. In reality, any system that requires perpetual growth for prosperity has the characteristics of a Ponzi scheme. The big economic problem of ending population growth, is that it exposes Ponzi schemes, and while these are common in financial systems, the later a Ponzi scheme ends, the bigger the problem, and all Ponzi schemes must end.

Japan has suffered from a “crash” resulting from economic indicators that fail following “peak child”, and China appears poised for a similar crash. In both cases, it is property Ponzi schemes that are hit hardest, and this is a huge problem for China. There is adequate proof that while those with the greatest wealth prosper during population growth, this is mostly due to increased inequity, and average wealth declines as population increases in any economy once past the point of needing more people to access resources.

Consequences: The ‘ageing population’ myth?

The second frequently pushed ‘pro-population growth’ message is the ‘ageing population problem myth‘. Again, already debunked by some of the best performing economies already having dealt with this ‘problem’. Reality is high birth rate countries like Niger may have fewer old people, but with 50% of the population under 15, there is an even higher ration of people requiring economic support than in countries with an ageing population. Note also, the countries with an ‘ageing population’ are performing better economically that those with high population growth.

What next: will population numbers stabilise, or even decline?

We know the immediate future.

The elusive ‘peak child’ has now been reached, so what now for future population? There are 3 possibilities for population from here:

1. decreasing.
2. stability.
3. return to increasing.

Whichever a person wishes to believe, there is a school of thought and material available to support that view.

Consider the year 2050. We already know the expected population for every age group over 30, as they have already been born, and death rates are reasonably predictable. Thus, for the next few decades, we know most of the story with future population. But as each decade passes, there is another 10 years of population at a size yet to be determined, making more distant predictions less reliable.

Each of the three possible reactions to learning we are at peak, as discussed previously, leads to its own school of thought as to what will or should happen in the future. I suggest which option people choose to believe is heavily impacted by confirmation bias. Either:

1. Peak child can’t be real population growth still continues.
   • Hopefully those with this initial reaction can see ‘it is real’, although yes, the problem of too many people remains. The number of children born continue to fall until we reach sustainability. Whether it is fear of the future, natural biological mechanisms or a combination of both, people are having less children, and for now at least, population growth is headed towards zero. Although it could still take year for growth to end and to find the right new level of stability.
2. Peak child is a threat!
   • It is consistent with this thinking to feel population numbers will continue to fall unless something can be done to prevent that fall. While I do not agree, that is a debate for another page, and this paper/page is about the reality of peak child.
3. Oh no, ending growth is an economic disaster!
   • Only Ponzi schemes require perpetual growth. In reality, the only scenario where ending growth is disaster, as opposed to a necessity, is where either growth could continue indefinitely, or at least beyond any time frame considered important. But those with this ‘growth, growth, growth’ thinking, will see ‘peak child’ as an abnormality, and expect population growth should resume.

The likelihood of alternative possible population futures.

1. In reality, a return to 20th century growth rates is not possible, but many still want it.

Before exploring the topic of population, I had assumed that the time I was living though must be typical, and that population growth as had been experienced must be normal. In fact, without really thinking about it, I simply assumed all species must always experience population growth, not realising the opposite is actually true.

The history of population during the last 12,000 years makes it very clear that the population growth rate of the last 2 or 3 hundred years was exceptional. The fact that ‘peak life on Earth‘ was 500,000 years ago and ever since the overall trend is for gradually less and less total life, makes it very clear that it is impossible for all species to be experiencing population growth. Rather, it means the increase in population of any species would always be counterbalanced by a decrease in the population of other species.

The evidence than the growth seen during the population explosion was growth beyond normal, unsustainable, and required decrease in population of many other species is very clear.

Perhaps those who believe the Earth is only 6,000 years old, or believe the scientific records are ‘just theories’ could retain my original beliefs when presented with this information, but otherwise that main reason for not coming to this thinking would be that, as was the case with myself not long ago, people have not seen the evidence.

The total amount of life on Earth is not increasing, so if our population increases, the population of other creatures decreases, and there has to be a limit.

All current data makes it clear that even one more doubling of the Earth’s population would be problematic, and two or three generations at 20th century growth rates would possibly triple the world’s population, which is unthinkable. The impact on the environment and other species would be catastrophic.

Clearly, that 20th century rate of growth could not continue even beyond one more generation.

Fortunately, current global birthrates suggest a return to population growth of the mid 20th century are not going to happen any time soon, but all it would take is a small increase in the number of children in the average family. In most countries, there is nothing, nor even any information campaign to ensure this dangerous outcome is avoided. In fact, in some countries, there are active campaigns for increasing birthrates, and this is not just restricted to the countries with the lowest birthrates. Australia, with the highest population growth rate in the OECD, has had governments with funded programs to increase population growth:

When introducing the baby bonus scheme in 2002, treasurer Peter Costello famously encouraged Australians to “have one for mum, one for dad and one for the country”. Costello would be happy to know as the baby bonus generation grows up, there will be a record number of Australians coming of age in the next decade.

Peter Costello’s ‘baby bonus’ generation grows up

Misguided advocacy for population growth is common, and a threat, but in the short term, growth rates have almost zero chance or likelihood of any return to growth-rates of the population explosion, with the possible exception of ‘immortality’.

2. Decades of population stability having now reached peak child.

Taking more complete account of human history reveals that specific recent factors or not, population levels normally show remarkable stability, however, on that basis these do not seem normal times.

When I first began this webpaper in 2019, this section stated:

With this model, working on the basis that human population trends towards reproducing at ‘replacement rate’ and population stability, assumes decades of remaining at the current peak child level, the global population will reach around 11 billion, and remain at that level until the balance is again disrupted.

Now, just three and a half years later, much has changed. With countries such as China having reach peak population far earlier than expected due to population growth rates dropping below replacement level. While if birth rates had remained at levels reported in 2019, a global population reaching 11 billion would be possible, but births rates continued to fall.

In 2019 my most likely outcome for “option 3: Birth rates fall until a new lower sustainable population”, predicted a peak population of 9 billion.

Now, I see that 9 billion peak population as the prediction even if birth-rates stabilise now. If birth rates do now stabilise, potentially the population could then stabilise at a level between 8 and 9 billion.

Even 8 billion people on Earth is proving a challenge for any form of stability. Although, numerically, population will likely be relatively stable for decades, it is very likely that birth rates will continue to fall, and very little else will experience stability.

Relative stability of total population number the is almost certain over the next few decades, but birth-rate stability for the next few decades seems highly unlikely.

3. Birth-Rates and Population will fall until humanity achieves new, lower, stable population level.

In a population where the individual lifespan is around 80 years, even a zero birthrate only sees population decline by 25% over 20 years, and zero births at all does not seem likely. Significant population decline would take decades, and in the next few decades it is likely a lot will change. Both human history and other examples of population in nature, suggest population stability is the normal, so a new population stability should arise.

However, what I did not realise on first publishing this webpaper in 2019, was that humans have developed societal evolution, which has resulted in an accelerating rate of change in who humans are and breaks from what is normal elsewhere in nature being applicable. Stability and ‘optimum population‘, no longer necessarily applies if the species, as with the case with humans, is itself changing.

Under this model, which is explored in more detail in the paper on optimum population responses, if the current global population remains unsustainable then in response the birth-rate may fall even further.

A stable population level could be achieved at 7 billion, but it seems unlikely there will be any real stability, with global population likely to then continue to fall gradually towards an even lower target if nothing significant interferes, but most likely, something will interfere.

4. Humanity reduces age related mortality rates.

Solving child mortality rates played the major role in triggering the population explosion. There were not more births, just less deaths. Now we are adjusting to this lower level of deaths though birth-rates seen as impossibly low even one century ago.

There is another step possible: age related mortality rates.

Most life on Earth does not age, as it consists of single cell organisms, that do no create new cells as offspring, but divide into two cells, both of which are in some respects still the parent cell. Ageing can be seen as a disease:

• Aging as disease (paper by Gunnar de Winer: National Library of medicine).
• Is Aging a Disease? Biodemographers’ Point of View (paper by L. A. Gavrilov and N. S. Gavrilova⁾
• Is Aging A Disease? (American council on science and health)
• Why ageing should be classified as a disease (The conversation, 2019)

Those are some sample articles, and it is a significant topic in its own right, but in summary, it possible that a second step, reducing age related mortality, could also be possible. The ethical implications are enormous, but so are the implications for population, and for birth rates.

Assigning a probability to this factor only makes sense when combined with a time frame. Within 100 years, I would regard this as quite likely, providing nothing seriously derails humanity in the interim, which could be even more likely.

The risks in future predictions.

Disasters?

Population numbers being significantly lower than projections, is likely only to occur following disasters. Disasters, do not only kill people, they also lower the carrying capacity of the Earth. A disaster that kills half the human population could result in a planet that, for a significant period, can only support half the previously population level. Further, society would likely be so disrupted by such an event that many systems simply fail, leaving the survivors without sewage, power, farming etc. Without all these systems, the Earth could feel more overpopulated than ever. So a disaster that decimates the population may make things better several hundred years later, but by the time things have recovered, the population could simply double again, with birth-rates like the 1960s capable of doubling the population in 30 years.

Climate change is one such potential disaster, but hopefully it can be averted. If fact, climate change and most other threatening disasters are all threats that arise due to Earth being above the carrying capacity.

Short of a disaster, the population cannot rapidly shrink. Remember the population pipeline. This year, the average elderly person do die would have been born 80 years ago when the world population was much smaller. To keep births to a level that only replaces a far smaller generation is a change that cannot happen that quickly.

Interference.

Some of the most influential people in the world benefit economically from population growth, and then there are others easily recruited to supporting population growth.

Even if some new social movement starts to reverse the trend of slowly decreasing birth numbers, the world dealing with environmental impact of the number of people we have will likely curtail any such movement.

Key to understanding what will happen with future birth rates is understanding what has happened that has caused rates to fall. In my opinion, many current theories do not stand real scrutiny, but even if these theories are correct, they also predict the trend in declining rates to continue. How far rates will decline depends on what theory you believe as to why rates declined, and I discuss that in leaving peak population.

Conclusion.

Peak child is here. It marks a significant change, and while there being a similar number of children year on year is a return to normal, for a world where generations have known nothing but unsustainable exponential population growth, some people will resist the change.

Updates.

• 2024 Feb 26 : Update in progress.
• 2022 October 28: Updates for newer information and clarity, particularly ‘what next?’.
• 2021 July 22: Added ‘Don’t panic, with link to updated “Wealth & Happiness Vs Population“
• 2021 Nov 20: Update & Analysis: Peak Child From 2017 Confirmed By Birth Records.
• 2019 Jan 12: First Draft.

In Progress and Future Updates:

• none outstanding