Article - S037

Human proliferation in perspective

Published on News24: 15 March 2018

Conspicuously absent in the Paris Climate Accord is any mention of human overpopulation. Surely the time has come for humanity to openly acknowledge that environmental decline is linked directly to our species’ unrelenting proliferation around the world.

Understandably, the subject of human population growth is highly contentious but, considering our civilisation could face unfathomable hardship or even extinction by the end of this century, it’s a subject we’re going to have to confront – sooner rather than later.

Exponential growth

It is estimated that in 50 000 BC the population of Homo Sapiens was around 44 000 individuals. By 1 AD it had risen to approximately 200 million. From there it grew steadily up until the beginning of the industrial revolution, after which our population rocketed from 1 billion in 1800 to 7,5 billion in 2018.

The exponential human population growth curve shown below resembles that of a cryptocurrency, although our curve isn’t expected to level off or tumble any time soon – not through voluntary means anyway.

(Refer to Graphic #1 at end of article) 


To fully appreciate the sheer magnitude of our human population, we need to compare it with the populations of other terrestrial megafauna (land mammals exceeding 40kg in mass).

For illustrative purposes, equate the human population of 7,5 billion to the height of the Himalayan Annapurna III peak – 7 500 metres. Then, consider the population sizes of other megafauna.

(Refer to Graphic #2)


Environmental displacement

Now, consider the fact that just 250 years ago, most wild megafauna species still numbered in their tens if not hundreds of millions around the world – even large ones. For instance, estimates put the African elephant and rhino populations at 30 million each, and the American bison population at 60 million prior to mankind’s prolific rise.

Thus, since ±1780 AD, the population of African elephants has declined by almost 99% (1 in 100 still exists); rhinos by 99,9% (1 in 1 000 still exists), and ‘pure’ American bison by 99,975% (1 in 4 000 still exists). In stark contrast, the populations of humans and our domesticated species have risen by over 600% – meaning that at least seven individuals exist now for every one that existed in 1780.

Simply put, since the start of the industrial revolution, soaring human and livestock populations have displaced almost all the world’s wild megafauna to the point of being classified as either vulnerable, endangered or even extinct.

Our civilisation’s unremitting seizure of wilderness area for urban expansion, development, transport infrastructure, pastureland and agriculture, has left nothing but fragmented enclaves for all the world’s remaining megafauna to exist.

And it isn’t just wild megafauna that’s been affected by this displacement phenomenon … it extends right across the full spectrum of our planet’s plant and animal kingdoms, including those in our oceans.

This fundamentally contradicts the notion put forward by leading environmental agencies that clean energy, reduced consumption and technology alone can lead to a long term sustainable future for other megafauna species.

The sad truth is, there’s almost no space left on Earth for wild megafauna to regain even a fraction of their original numbers … certainly not while our population continues to grow, and our agricultural footprint continues to spread.

Proliferation set to continue

According to the following UN population graph, our human population is projected to reach 9,3 billion by the year 2050, assuming a medium fertility rate; and possibly even 10,6 billion assuming a high fertility rate.

(Refer to Graphic #3)


This forecast population growth will undoubtedly further exacerbate the environmental displacement trend by threatening the world’s last remaining wilderness areas and wildlife.

The bulk of this population growth is set to take place in developing nations as shown in the following BBC world population graph.

(Refer to Graphic #4)


The combined population of developing nations is projected to rise from 6 billion today, to 8 billion in 2050, and then to over 9 billion by 2100 (assuming the medium fertility rate used by the UN).

On the African continent alone, the human population is forecast to grow from 1,25 billion today, to 2,5 billion in 2050, and then to 4,2 billion by 2100 – as depicted in the UN graph below.

(Refer to Graphic #5)


With so many of Africa’s rainforests, savannahs, lakes and megafauna species already threatened across the continent, one has to ask how they will survive the doubling of the human population over the next 32 years … and then the almost doubling again over the 50 years that follow after.

Carbon footprint inextricably linked to population growth

Although a handful of sceptics dispute that manmade CO2 emissions are linked to climate change, no one can dispute that CO2 emissions are directly linked to human population growth – as shown in the following dual-axis graph.

(Refer to Graphic #6).


Considering how closely linked our population growth and CO2 emissions are, it’s difficult to imagine how humanity can adequately reduce its carbon footprint without a monumental global initiative to at least stabilise our population growth and follow the UN’s ‘low fertility’ curve.

There’s no doubt that the roll-out of renewable energy and carbon-neutral technologies will have an impact, but to believe that they alone will be sufficient to meet the highly optimistic CO2 emission reduction targets recommended in the Paris Accord is simply reckless.

The following graph published by The Guardian emphasises just how drastic the CO2 emission cuts need to be to give our civilisation a 50% chance of not exceeding the critical 2°C global average temperature increase limit … beyond which lurks an unknown degree of climate anarchy and environmental catastrophe.

(Refer to Graphic #7)


Consider that by 2100, annual carbon emissions will need to be reduced to a level last seen in 1850 … with a consumer-driven human population between 6 and 15 times larger than it was in 1850. 

The unfortunate reality is that unchecked population growth will undermine even the most sincere and radical efforts of nations to achieve the Paris Accord’s CO2 emission cut recommendations.

Step aside rats

If the size of our human population hasn’t quite sunk in yet, consider that there are approximately seven billion rats living on Earth. Human beings now outnumber rats by half-a-billion. (Spare a thought for the three Northern White Rhino left on Earth…)

If we’re not prepared to draw the population plateau somewhere, our species will continue to proliferate until such time as we experience an involuntary and unprecedented population correction – most likely caused by mass-starvation resulting from climate change-induced environmental collapse.

Time is of the essence for the human race to acknowledge the seriousness of the fast-approaching apocalyptic fate that awaits every single one of us. Thus, we must not hesitate to initiate the conversation regarding the stabilisation and gradual reduction of the human population to a point where it harmonises with the sustainable carrying capacity of our planet.

Only through constructive dialogue can we devise innovative and socially acceptable ways to minimise population growth, by encouraging a global movement towards smaller families and reducing the incidence of unplanned pregnancies.

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Graphic #1

Human Population Growth Curve

Graphic #2

Population Size Comparison Table

 Key: m – Metres; cm – Centimetres; mm – Millimetres 

Graphic #3

UN Human Population Growth Projections

Graphic #4

Population Growth Projection (Developed vs Developing Regions)

Graphic #5

UN Population Growth Projections for Africa and Europe

Graphic #6

World Population vs CO2 Emissions Growth Curves

Graphic #7

CO2 Emission Cuts Required as per Paris Climate Accord

Key: CO2 emissions since 1850 (red); exponential growth (blue); cuts to hit climate target (dashed).