Peak Child: When, and what does it mean?

Peak child is a key indicator of population growth trends. The first point about ‘Peak Child’ is to understand this key concept. The second point about Peak Child is the rather amazing fact that the world may have already reached peak child. This is a truth so contrary to preconceptions that even after seeing the data, it still seems hard to digest. The implications include the future of investments, economics, global warming, and how we picture the future of humanity.

Whilst long term population growth is not the normal state for an species, humans have experienced a population explosion over the most recent few centuries such that our entire economy requires adjustment to deal with the end of the population explosion.

What is ‘Peak Child’.

Peak Child is when the number of children has reached the maximum number it will reach, and is step 3 the journey to understanding population.

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“.

At a global level, due to the absence of immigrants to the Earth for other planets, ‘peak child’ is a precursor to peak population. For the global population to reach a plateaux, first number of newborn children must plateaux. Ten years later, the number of 10 year old reaches a peak. Twenty years later, the number of twenty year old people reaches the highest number it will ever reach, etc., until within a lifetime or about 80 years, no age group is increasing in population any more.

‘Peak Child’ can occur anywhere between 0 and 80 years (up to approximately 1 lifetime) prior to peak population, and more typically would occur approximately at 1/2 of one lifetime before any peak population level.

Globally, peak child is determined by the ‘births per woman’, which as a global average has been falling since 1960.

For an 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. A growing population will give birth to more children than ever before, even without a birth rate that itself drives that increase.

The exact definition of ‘peak child’ varies in 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 only, children zero to five year 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.

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.

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

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. He stated the world is at peak child in 2014, when the ‘births per woman’ was at 2.5. Now, in 2019 it still marginally abover 2.4, and the magic number, thought to be ‘between 2.4 and 2.2’, will be reached at the earliest by 2020, and at the latest by 2034. So for ‘peak child’ to have been already reached in 2014, it definitely have to include all children under 18. Overall, you could argue that Hans was a little early, but not very early. We are basically now at peak child.

How did we get here: the global drop in births per woman.

This arrival at ‘peak child’ is the culmination of 60 years of continuously falling rate of ‘births per woman’, which has fallen from 5 as a global average around 1960 when the population growth was out of control, to just over 2.4 today. Hans Rosling is the expert on the maths of how we got to here, and he has many theories on why the population has moved to a new stability, as do so many others, but one of the best theories is this: it is in human nature to reproduce at close to a stable population.

Throughout human history, for all but the period for 1500-2000, humans reproduced at rate just slightly above a stable population. In Hans Rosling’s words ‘they died in balance’, but that required reproduction in balance with the number of children who would survive. As medicine in improved, survival improved, and birth rates fell. One theory would be that it took time and created a population explosion as humans adjusted, but we have now adjusted to a ‘new normal’ where very few children die before adulthood.

OK: So Why do we still have Population Growth?

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.

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.

The Gap: Another 3 Billion?

At the time of writing the world population is over 7 billion. If the projections follow the path calculated by the late great statistical and medical researcher Hans Rosling and others, ‘peak child’ will not mean the end of population growth until there are 11 billion people on Earth. There are other estimates both slightly lower and slightly higher, but these are the agreed estimates at this time. Even more disturbing for the overpopulation ratio, is that the environmental impact per person will likely increase on average as more of the world becomes developed.

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

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’. 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, peak child did mean more births, but these were offset by child deaths. Given it is 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. These is largely a fear of change, with many economic systems currently still tuned for the population explosion. Yet some of the best performing economies are either already post population growth, or at the stage where their only growing population demographic at this time, is the retiree group.

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’.

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

That ‘peak child’ has either already been reached, or even by the most pessimistic readings will soon be reached on current trends, confirms a trend of reduction in population growth. How long this trend will continue is not clear, but the trend seems unlikely to end prior to some fall from our current population.

That is, there could be a population decline for some time, but all evidence from nature would be that this would be a correction before population again stabilises as throughout nature all species that are not subject to competition from a new species achieve a stable level of population.

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 birthrates 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 because the 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.

Can the population grow higher than estimates? Unlikely. 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.

8 thoughts on “Peak Child: When, and what does it mean?

Add yours

  1. “At the time of writing the world population is over 3 billion.”
    When was this written, 1950? that’s when the population was about 3 billion, it’s almost EIGHT BILLION NOW!!!
    We are far beyond anything near sustainable & being DEPENDENT upon DECLINING OIL, COAL & NATURAL GAS, our ability just too feed ourselves is in decline & it will get worse.
    We should have started decades ago, like in 1920 to STOP GROWING & stabilize it at ONE billion.
    Instead our RULERS FORCED us to keep having children & continue to do so.

    I also fear we are out of time for a painless reduction in our numbers, too many religious & uneducated people, too many people without access to sex education, birth control & the MORONS in control of many of our states is again BANNING ABORTIONS! “They” our RULERS, want to FORCE US TO KEEP BREEDING SO “THEY” CAN PROFIT!
    Their are too dam stupid & greedy to realize that they cannot profit on a DEAD PLANET!


  2. The 3 billion was a typo. A pretty bad typo, but the section heading says ‘another 3 billion’ and later text says ‘growth until there are 11 billion’ so there were hints it was a typo.

    Beyond the typo, well said. I agree. Maybe we disagree on details, but that we should have started back in 1920, instead of starting, and too slowly, in 1960. Yes, yes. And that now we are overpopulated and that it is a huge problem.

    Still, the number of children being born today is no longer driving growth, and now our problem is dealing with the backlog.

    This entry is an exploration of ‘peak child’, what ‘peak child’ means, and why ‘peak child’ alone does not stop population growth for many years to come. You have me thinking though, and I will soon explore what is needed to stop population growth right now. I suspect it would be something like a global 1 child limit, but desperate times call for desperate measures, and these are desperate times.


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