We now know that the human population has already expanded beyond the capacity of earth’s sustainable resources. It matters that future generations have an acceptable quality of life and that the human race, through uncontrolled growth, does not destroy the one home it inhabits.
1973: Four billion
When I was a student in Oxford in the early 1970s, I spent a little time studying demography. In the year when I wrote an essay on this subject (1973), global population was estimated to be around four billion, having grown by around one billion since 1960. A frighteningly steep upward curve in numbers was already in evidence.
When asked by my tutor why I had chosen this option, I replied: “Because people matter.”
2023: Eight billion
As we entered 2023, the United Nations Department of Economic and Social Affairs had recently announced that the world’s total population had reached around eight billion people, having doubled in the previous 50 years. The UN called for solidarity in advancing sustainable development for all, but there was little or no discussion in the media about the burgeoning population being itself one of the biggest threats to human life on the planet, nor that we could be heading for 10 billion people by the late 2050s, as Population Matters, a UK based charity supported by Sir David Attenborough and other distinguished patrons, has shown.
Can technology keep pace with population growth?
My studies had introduced me to the theory of Thomas Malthus, an English cleric who, in 1798, predicted that unchecked, population would always grow exponentially. By contrast, Malthus argued, food production could grow only linearly. He concluded that lack of resources, primarily food, would therefore ultimately limit population growth.
As time passed, it became generally accepted that, since the industrial revolution, Malthus’s theory had lost its validity. His critics pointed out that expansion of agriculture, new technologies, rising economic growth per capita and globalisation had largely enabled food supplies to keep pace with population growth at global level.
However, this assumption is now being sorely put to the test by the fall-out, in terms of disruption to food supplies, from the Ukraine war, as well as increasing floods and famine, largely due to climate change. It also implicitly ignores the fact that rising standards of living are placing an intolerable burden on the global environment.
According to One Planet, a UN-supported multilateral network, our global footprint is already about one and half times the Earth’s total capacity to provide renewable and non-renewable resources to humanity.
Is the rate of population growth slowing down?
Detractors of Malthus can also point out that, following a peak of 2.2 per cent in the early 1960s, the annual growth rate of global population has started to decline. This means that for decades, the world population has technically no longer been growing exponentially. The time gaps between each successive billion people have been relatively stable, with around 12-13 years for each additional billion to arrive between 1973 to 2023. This reflects the fact that today, two-thirds of the global population live in a low fertility context, where lifetime fertility is below 2.1 births per woman.
Late 2050s: Ten billion?
However, the latent continuing linear growth in population still represents a grave threat to sustainability. According to Population Matters, although the growth rate is now less than one per cent per year, because our total population is more than three times larger than in 1950, the absolute annual global increase is more than 60 million people per year. The UN estimates that we will reach nine billion people in 14 years’ time in 2037 and 10 billion by 2058. It foresees the overall global figure peaking at around 10.4 billion in the 2080s.
The consequences of this are explained succinctly in the book Ten Billion, by scientist Stephen Emmott: “In short, as population increases, and as economies grow, stress on the entire system accelerates sharply.”
Climate change is of course closely linked to population growth, as increasing consumption tends to increase emissions of harmful greenhouse gases. At the same time, conventional food production is set to decline, because of climate change, desertification and water stress. The loss of bio-diversity, eco-systems and forests could also pose a threat to human survival. Meanwhile more and more people are exposed to climate-related risks, especially in poorer regions, leading to increased migration pressures.
Radical solutions are clearly needed to these complex and serious issues in order to maintain global sustainability.
Greener, leaner life-styles
Of course, the environmental impact of life-styles in higher income regions is far greater than in poorer ones. Those of us in richer countries need to consume less and conserve more. We urgently need governments to mandate sustainability strategies as integral in food, energy, transport and all other areas of economic and social policy.
Education of women
Lower-income countries in particular, need help to support education for women. In Bangladesh (pop.179 million) for example, improved women’s education and government-sponsored family-planning programmes have resulted in a dramatic decline in women’s fertility since 1985, from 5.5 to 2.1 births per woman at the present day. The UN advocates that “all population policies must have reproductive rights at their core, invest in people and planet, and be based on solid data.”
Malthus had a point
We need to come to terms with the fact that our still rapidly growing population poses a threat to human survival. Malthus is proving right after all, in his understanding that, no matter how large the resources and how advanced the technologies, with only one planet, they are still finite.