One Finite Planet

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Peak Child: When, and what does it mean?

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Why Population growth even before the explosion?

Throughout history, although no other species on Earth has experienced such long term overall population growth, even before the recent population explosion, the human population kept slowly growing.

Yes, we recently had an unprecedented population explosion, driven by is hidden by by the near elimination of previously tragic infant mortality, but against the background of long term growth, many of us never didn’t even realise their was an explosion.

But what drove population growth even before the explosion? What will now happen as the explosion ends?

Read More »

Population Explosion: What happened to get to 8 Billion people?

Humanity has just experienced a population explosion. Whether you believe we are overpopulated or not, the facts are that we have just had a population explosion.

Over two centuries of population peaking at 50x higher than the long term population growth, and peaking at 100x higher during the baby boom.

Yet the explosion occurred with women having less babies than ever before, even during the baby boom, and is ending all by itself.

So what caused the boom, why a population explosion when birth rates are falling? Will our population grow until we are living life like battery hens?

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Paradox Resolved: Educating women didn’t end the Population Explosion.

Surprisingly, humanity is at ‘peak child‘ and looks to be heading to population stability and perhaps even ‘leaving peak population‘ and correcting to a lower population.

We still have an overpopulated planet, following the population explosion, but the explosion is ending, due to ‘births’ per woman falling from over 6 prior to 1900, and to around 2.3 in 2021.

There is much confusion over why birth-rates are falling, with “education of women” often mistakenly given as an explanation, but no, the Taliban are not onto something, and rather than this or other common coincidence theories, it seems far more likely people are motivated to have the number of children that are appropriate for the situation.

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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.

Return to peak child means we could either return to the gradual growth levels of prior to the industrial revolution, or become a mature species, and exist in balance with nature and other living things. Perhaps even stop displacing other species?

Peak Child: When, and what does it mean?

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.

Return to peak child means we could either return to the gradual growth levels of prior to the industrial revolution, or become a mature species, and exist 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:

  1. This ‘peak’ can’t be real, because population growth is still spiralling out of control! Growth must stop NOW!
  2. Peak child is a threat because falling fertility rates are a threat to the survival of our species.
  3. Oh no, economic disaster! If this is true, then customer bases will stop growing, ending our perpetual exponential economic growth.

If you are in group #1: “It can’t be real”, then this page should provide good news with the evidence that ‘peak child’ is now real but bad news in that not all challenges of population growth are yet solved.

For anyone in the group #2: “Peak child is a threat”, I recommend the page “Optimum Population: birth control in nature” for exploration on why birth rates are falling and are unlikely to fall too far. However, as it taken me 7 years to realise even the obvious observations of that populations of other species are stable over the long term, allow time for it to make sense. This current ‘peak child‘ page also looks at consequences, and how population has been relatively stable for most of human history.

For anyone in group #3, despite some economists being hooked on the continuation of Ponzi schemes, meaningless economic activity and advocating for population growth, the statistics, as explored in pages such as “Wealth & Happiness Vs Population“, all show economies with lower population growth deliver far better outcomes for their citizens.

Perhaps it is time to be adults and realise that the best growth from now is no longer about an increase in size, especially when taking into account we exist on a planet where the peak amount of all life was 500 million years ago, and the sum of all life is slowly declining. Only be reducing other populations of other life can we increase our population.

No one should panic, as peak child is good news for personal wealth and happiness, and for the planet, and is only a return to the normal rate of population growth for humans.

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, and we largely defeated the diseases ‘preying’ on our young, and this for humanity, was just like experiencing less predators.

The total amount of all life on Earth is declining from ‘peak life‘ around 500 million years ago, not increasing.

Even if humans do not destroy the planet, the total amount of life on Earth will reduce until no complex life remains in as little as 25 million years.

Because the total amount of life on Earth is not increasing, sustained population growth for humans requires continually displacing other species and reducing the populations of other species. In fact, humanity has our own form of societal evolution that has enabled displacing other species even before the population explosion. Farming improved, and our chosen food sources have been assisted to outcompete other organisms, which provides for the increased population.

However, unlike population growth prior to the explosion, which was driven by advances in society, population, during the explosion primarily increased due reduced deaths, particularly reduced chid deaths. There were still advances and improved food production may have supported the population explosion, but the result is so far unsustainable, which suggests overpopulation.

Either further advances are required to catch up with our population, or a reduction in population is required to restore sustainability, or some combination of both. What is needed is a new sustainable ‘optimal’ population. Stable population alone is not enough.

Humanity has spent most of the 300,000-year history are relatively static population, with population increases periodically in response to new advances. The overall pre-history graph would most likely have steps, with the top of each step representing stability, and long periods of ‘peak child’ while on each step. At least, this is what we observe with other species. Every species existing in a finite planter that has passed ‘peak life‘ and total amount of all life is slowly decreasing, can only increase in population by displacing other species. For humans, eventually it becomes problematic to keep eliminating other species, as there is a limit to the other species it is possible to displace and maintain the ecosystem.

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.

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?

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:

Australian government concern for the planet is not limited to emissions.

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:

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.


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.


  • 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