One Finite Planet

Peak Child: When, and what does it mean?

Current Update: July 22nd, 2021

First Published:

Table of Contents

Globally, the when is now. Although locally, experiences differ by location.

Data now clearly confirms that globally, the world has returned to 'peak child', a precursor to a likely return to peak population, following three centuries of a population explosion.

Reaching peak child again means we could again be a mature species, will soon return to existing in balance with nature and other living things. Perhaps even stop displacing other species?

Globally, the when is now. Although locally, experiences differ by location.

Data now clearly confirms that globally, the world has returned to ‘peak child’, a precursor to a likely return to peak population, and the end of three centuries of a population explosion.

Reaching peak child again means we could again be a mature species, will soon return to existing in balance with nature and other living things. Perhaps even stop displacing other species?

Don’t Panic.

There are at least 3 reactions to hearing the planet is reaching peak child:

  • It can’t be real, as population is still growth is still spiralling out of control.
  • This is a problem because falling fertility rates are a threat to the survival of our species.
  • Oh no, economic disaster! If this is true, then customer bases will stop growing, ending our perpetual exponential economic growth.

If you are in the “it can’t be real” group, then this page should provide the evidence that ‘peak child’ is now real, but does not mean the challenges of population are all solved.

For anyone in the “peak child is a problem” group, I fully understand. You may already see peak child is real, and more concerned about falling fertility rates that you ever were about over population. I recommend the page “Optimum Population: birth control in nature” for why rates are falling, and are unlikely to fall too far. However, as it took me 7 years to realise even the obvious observations of that page, allow time for it to make sense. This current ‘peak child‘ page also looks at consequences, and how population has been stable for most of human history.

The economics of why ending population growth means more wealth for most people is explored in pages such as “Wealth & Happiness Vs Population“, but in summary, peak child is good news for personal wealth and happiness, despite some economists being hooked on the continuation of Ponzi schemes.

What is ‘Peak Child’?


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.

‘Peak Child’ is not the same as peak population, and can occur even when a population is still growing. Realising we are at key child was a key step in the path to my current understanding of population.

The transition to peak child would normally occur, as is the case currently, as a population growth period is approaching its end.

While peak child can occur anywhere up to one lifetime (between 0 and approximately 80 years) prior to peak population, it would typically occur around 1/2 of a lifetime prior to peak population, depending on the severity of population correction required.

Understanding that we are at peak child, even though not yet peak at population, was step 3: “it is better than it looks” on my journey to understanding population trends.

The exact definition of ‘peak child’ varies from source to source, due to one nuance: ‘What counts as a child?’ From birth, until what age, should count in the total for ‘peak child’? In different articles, different ages are chosen. It can be children in the first year of life only, children zero to five years old, or even all children under the age of 18. Which ‘upper limit’ is chosen can make a difference to when ‘peak child’ occurs, and to when.

Reaching peak child is determined by combination two factors:

  • Births per woman‘, which as a global average has been falling since 1960, being at or below the level for population stability, which is between 2.2 and 2.4.
  • Child and adolescent mortality, which determines the percentage of those born, who live to have the opportunity to have their own children.

Peak Child, Planning and The Ripple Effect.

Reaching ‘peak child’, allows a society can plan for a maximum number of newborn children year after year, meaning that child birth facilities may continually be upgraded and improved, but they will no longer need to continually be expanded.

Once there has been ten years at ‘peak child’ stability, the number children of all ages up to 10 will reflect the peak level. From that point forward, instead of always expanding facilities all, we can concentrate on improving all facilities, not just for newborns, but for all primary school students.

Twenty years after reaching ‘peak child’ then number of all children would then be stable, and schools, colleges and universities, can all focus on being able to support a static number of young students going forward.

For a given country, reaching peak child means the number of schools can remain static and no longer need to handle expansion. Facilities for each demographic over time will also reach their peak requirement, unless changes to immigration or trends take place.

This effect of stability takes a lifetime to ripple through all age groups.

Peak Child Vs Peak Population.

At a global level, due to the absence of immigrants to the Earth from other planets, ‘peak child’ is a precursor to peak population. If ‘peak child’ is sustained until all people were born during a time of peak child, then the global population must reach a plateaux.

With ‘peak child’ occurring at 2020, it logically could take another lifetime until all age groups were born at those ‘peak child’ numbers. Until that time, which would be around 2100, since the elderly would be those bone in lower than ‘peak’ numbers, the number of people dying would be too few to balance those being born, so the population continues to grow.

As discussed below, it is logical humanity will progress from peak child to peak population, and it could happen long before 2100.

Global Peak Child vs National Peak Child.

At the national level, ‘peak child’ only means that for every country where the number of children is still increasing, there is another country balancing the numbers.

In practice, there are counties such as the USA, Canada, Australia and even the UK, where, despite birth rates that should result in population decrease, immigration numbers result in population increase. Then, there are countries, almost always poor economically, where birth rates alone still result in population increase.

For any individual country, the link between the number of children and ‘births per woman’ is weakened due to immigration and emigration. For example, even with a ‘births per woman below 2.0’, the population could grow due to immigration, which is the reality for the USA, and many other countries with high net immigration. A growing population will result in an ever increasing number of children, even if the birth rate is not driving the increase, as with the US currently.

So peak child is at this time a global phenomenon, affective global society and the global economy, but with individual countries still dealing with internal circumstances.

Peak Child Is Natural, Normal, And Now Follows Not A ‘Boom’ in Births, But Reduced Deaths.

Humanity has just experienced a population explosion, but it was not due to a boom in births, but instead a reduction of infant mortality. Animals that reproduce in numbers which allow for predation can experience population booms when there are less predators, we largely defeated the diseases ‘preying’ on our young, and this for humanity, it was just like that.

Normally sustained population growth results from evolution that enables displacing other species and reducing the populations of other species, as a result of that evolution. In fact, during the explosion, humans have improved farming and now have our chosen food sources outcompete other organisms, providing for increased population, but the increase in population was in response to reduced deaths, and our improved food production limited the impact, even though the result has still not been sustainable, which suggests we have been battling overpopulation.

Clearly our a new, ongoing ‘optimal’ population is possible, when that is reached birth-rates should again result in stability.

Humanity has spend most of the 300,000 year history at some population plateaux, even though we have a history of moves to a higher plateaux which result in brief burst of growth. The overall graph would have steps, with the top of each step representing stability, with a similar child population year after year. Every species existing in a finite environment can only increase in population by displacing other species, and eventually, it becomes problematic to keep eliminating other species, or you run out of species to displace.

Long term population growth is not the normal state for any species, and while humans have just experienced a population explosion over the recent three centuries, peak child is a result of humans adjusting birth-rates to return to population stability.

These is a problem that our entire economic system evolved during the explosion, and now also requires adjustment to deal with the end of the population explosion ,as countries such as Japan have learnt and China is poised to learn, but as a return to a historical normal, we can adjust and individuals will benefit as a result.

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

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

The great Hans Rosling.

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.

Ourworldindata: Interactive

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.

Peak child is a key indicator of population growth trends, and understanding the concept of ‘Peak Child’ is critical to and journey to understanding what is happening with population. While is seems hard to believe the world has reached peak child, it seems equally hard to believe this target has been reached without the world 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 relief for those fearing global warming, extinctions, and reduction in income inequality that results from population growth. While there are adjustments required, only billionaires looking to increase wealth at the expense of larger population 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’.

Normally, even where there is population growth, it is so gradual that the number of children year after year will show no noticeable change, even over a century.

Population growth of the recent explosion would carpet the entire surface of the Earth with humans within a few thousand years, and humans have existed for at least 300,000 years, so for almost all of those 300,000 years, humans have existed in a state of ‘peak child’. Prior to reducing infant mortality, there were more children per family, but as these were offset by child deaths, the population was stable. It has never been a problem existing in a state of peak child previously, or we would be extinct. It will, hopefully and most likely, not be the last peak child either, although perhaps the next population explosion will only 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 is not only fear of change, but also reflects that many economic indicators are tuned towards perpetual growth of either tax revenues , or the results of only the largest companies. Yet some of the best performing economies are either already post population growth (e.g. Germany), or at the stage where their only growing population demographic at this time, is the retiree group (e.g. China). In reality, any system that requires perpetual growth for prosperity has the characteristics of a Ponzi scheme.

Japan has suffered from a “crash” resulting from economic indicators that fail following “peak child”, and China appears poised for a similar crash. 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 with sufficient 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 less 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?

The elusive ‘peak child’ has now been reached, so what now for future population? Whatever you wish to believe, there is a school of thought and material available to support that view.

Consider 2050. We already know the expected population for every age group over 30, as they have already been born. For the next few decades we know most of the story with population, but as each decade passes, there is another 10 years of population at a size yet to be determined.

Each of the three possible reasons why we are at peak child leads to a school of thought as to what will happen in the longer term with population. I suggest which option people choose to believe is heavily impacted by confirmation bias. Either:

  1. Population will keep growing for ever, and ‘peak child’ is an abnormality that will come to an end.
  2. Humanity will remain at this ‘peak child’ level for decades to come, resulting in population growth slowing to zero in coming decades.
  3. 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, awill now stabilize, for now at least population growth population growth is headed towards zero, although it could still take time to get there.

Longer Term There Are Three Possibilities, Confirmation Bias Impacts Beliefs.

1. Population Growth Will Return.

Simple maths, plus history of the last 2,000 years makes it very clear that the population growth rate of the last 2 or 3 hundred years is an exception, but for those who believe the Earth is only 6,000 years old, or like to ignore mathematical analysis of the time prior to records of population, it can be believed that while this does not happen long term for other living things, significant population growth is normal for humans.

With the mindset that population growth is normal for humans, comes the ideology that the factors that brought the reduction in birth rates must be overcome, so that growth can be restored. This mindset is strongly is promoted by those that profit from farming humans, and there is significant campaigns to promote this position. Move over big tobacco and big oil, we also have big population.

If this vision of the future is realised, despite the Earth being finite, there is be no limit to the human population.

2. Population Growth Will Head Towards Decades Of Stability With Births At Remaining At Reached Peak Child.

Taking more complete account of human history reveals that specific recent factors or not, population levels normal show remarkable stability.

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.

3. Birth-Rates And Population Will Fall Until Humanity Achieves A Sustainable ‘Normal’ Population, As Large As Sustainably Possible.

This model, follows not only human history but also other examples of population in nature, and proposes that the observed population stability, arises from the fact that the maximum sustainable population normally remains stable for long periods of time.

Under this model, which is explored in more detail in the topic ‘optimum population‘, it is possible that the current global population is unsustainable and in response the birth-rate may fall even further.

With this model, the global population may peak below even 9 billion.

The risks in future predictions.


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.


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.


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.


In Progress and Future Updates:

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