Last month, while the world was distracted by a stray missile landing in Poland, Donald Trump announcing another presidential attempt, and NASA returning to the moon, humanity passed a significant milestone right here on Earth. The global population clocked over eight billion.
Twelve thousand years ago, there were fewer people on the planet than now live in Sydney. In 1922, there were a quarter as many humans as there are now – we’d made it to two billion. Despite countless calamities, twelve years ago there were seven billion of us. That sounds like an exponential curve – and in nature that’s normally a sign of something being seriously wrong – but demographers point out that the population growth rate has been falling slightly since the 1960s.
Still, cities have never occupied as much territory as they do now, and the strain on our fellow species is unprecedented, as humanity demands an ever-greater share of what remains of a limited pool of resources.
So, what is the ‘carrying capacity’ of our world, in terms of homo sapiens? And how many of us might there be?
Nine, ten?
By 2037, the United Nations is expecting nine billion humans to be living on the planet, but based on current trends, demographers say there will never again be more children alive than there are right now, with fertility rates falling across the world.
At the same time, longer human lifespans mean that forecasters are anticipating a peak of ten billion or more before numbers start to creep back down.
Population density varies massively, with 1,315 people per square kilometre in Bangladesh, and an incredible 8,000 people per square kilometre in Singapore (that’s 2,000 times as dense as Australia). Across the board though, fewer babies are dying, more women are being educated and surviving pregnancy, and technological innovations are extracting more food from less surface area.
Simultaneously, deserts are expanding, global fish populations are crashing, pollution is worsening, and waste of all kinds is growing out of control.
Population growth across the planet is far from uniform, with India set to take over from China as the most populous country in the next few months. Other fast-growing population centres include Pakistan, the Philippines, and five countries in Africa; all places in the firing line of a rapidly warming world, while the populations of a number of ‘first world’ countries are already in retreat.
As has often been noted, humanity theoretically grows and kills enough food to feed itself, but problems of inequity and distribution continue to mount, raising the spectre of unprecedented famine, along with record human population.
Considering technological change, it also seems likely that there will be less and less work for a growing human population to do, and little enthusiasm among most governments to get their people off the growth and consumption merry-go-round that fuels the profits of the world’s corporations.
An ageing and growing human population, living within a threatened biosphere, means fewer taxes to pay for multiplying problems, both within countries and externally, as inequities fuel wars and revolutions. Disease is likely to be a growing problem, particularly for the poor. Ecological collapse appears to be around the corner in many parts of the globe, and the nuclear threat remains with us too.
The meaning of life?
Meanwhile, and in spite of everything, for the great majority of human beings, reproducing remains the central priority. Children are the principal source of joy, meaning, hope and comfort in old age, for almost everyone.
The selfish gene doesn’t care if it’s living in a Petri dish – its goals are more shortsighted than that, and for most of human history that has served us well, as we’ve learned to live in the most inhospitable corners of this planet, and adapted to our own destructions and stupidities as well, at least in the short term.
The fact remains, however, that despite the efforts of a few billionaires to reach beyond this world, there are limits to growth, and human population, and these are not just physical.
As we expand, we are an increasingly lonely species, crowding out our fellow life forms from the only biosphere we know. We have less time and space for other earthlings, and we hunger to replace them with virtual equivalents.
Wild animals are steadily being swapped for animal slaves, and plants (which created the conditions for us and all other animals to exist on this planet) are too often honoured only for their short-term human uses.
As our numbers grow, an epidemic of mental illness swallows the young. Diversity in all its forms is under threat. The places that our ancestors loved are being destroyed to create energy and homes for more humans.
One question is never answered as we multiply: How much is enough?
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