Reducing inequality could see world population fall to 6 billion

The global population will peak at 8.6 billion in 2050 and decline to 7 billion by 2100 if current trends continue. That is the projection of a model developed as part of an initiative from the Club of Rome non-profit organisation, and it is 2 to 3 billion less in 2100 than other recent forecasts.

This Earth4All model, created to explore which policies would deliver the most good for the majority of people, also suggests that if the world invested in a “Giant Leap” to reduce poverty and inequality, the world population would peak at around 8.5 billion people in 2040 and decline to 6 billion by the end of the century.

“Even if the numbers are not going to be as scary as some older forecasts, this does not mean that we don’t have a problem,” says Beniamino Callegari at Kristiania University College in Oslo, Norway, one of the authors of the Earth4All report.

A big fall in the world’s population will help alleviate environmental problems, but, by itself, won’t prevent us reaching tipping points where we risk destabilising Earth’s life-support systems, says team member David Collste at Stockholm University in Sweden.

“The population is not the only part,” says Collste. “It’s what people do, how they do it and how much they do it.”

A falling population will also decrease the proportion of working-age people, making it harder to finance healthcare and pensions. “The transition is not going to be easy, because it means a significantly older population,” says Callegari.

While these latest projections are the lowest ones yet, all recent global demographic projections suggest that the world population will start to decline by the end of the century as a result of people having fewer children.

“It would require a tremendous effort to overturn this,” says Callegari. Countries such as South Korea that are trying to stop their populations falling haven’t managed to do so, he adds.

The United Nations says the number of people in the world passed 8 billion sometime last year. It projects that the global population will grow to more than 10 billion before beginning to decline around 2100.

The UN’s forecasts are based on extrapolating existing trends in population numbers and don’t take into account the causal factors determining how many children people have or how long people live.

Independent groups that factor in the causal factors behind population trends have come up with lower estimates. For instance, Stein Emil Vollset at the University of Washington in Seattle has modelled population growth based on factors such as the level of education of women and access to contraception. In 2020, his team projected that the population will peak below 10 billion around the 2070s and fall to around 9 billion by 2100.

The Earth4All model is more complex and includes environmental, economic and social factors – such as food production, income, taxes, energy and inequality – and the feedback loops between these factors. It also incorporates the expected impacts of global warming and uses GDP per person as a proxy for educational attainment and access to contraceptives.

While Earth4All’s business-as-usual projection is well below the “most likely” projection from Vollset’s team, it is “within the range of our scenarios with faster progress in female education” with those who need contraception being able to access it, says Vollset.

To achieve its faster Giant Leap decline in the total number of people, the Club of Rome initiative is calling for a push to improve well-being for everyone on the planet.

This would involve: reducing poverty by investing trillions of dollars in green jobs and cancelling debt; reducing inequality by raising taxes on richer people; improving gender equality by ensuring more women get a better education; promoting diets that are healthier and greener; and electrifying everything that can be electrified and generating that electricity from renewable sources.

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