World population would reach 8.5 billion in the 2050s and then decline

Just at the end of last year the world population surpassed 8,000 million people and a recent study predicts that it will reach 8,500 in the next 30 years.

A new analysis suggests that the world's population could peak at just under 9 billion people in 2050 and then start to decline.

The new projection is significantly lower than several leading demographic estimates, including those from the United Nations. The researchers go further and say that if the world makes a "giant leap" in investment in economic development, education and health, the world population could peak at 8.5 billion people by mid-century.

For the new projections from the Earth4All initiative researchers for the Global Challenges Foundation, a new system dynamics model, Earth4All, was used to explore two scenarios of this century.

In the first scenario – Too little, too late – the world continues to develop economically in a similar way to the last 50 years. Many of the poorest countries rise out of extreme poverty. In this scenario, the researchers estimate that the world population could peak at 8.6 billion in 2050, before falling to 7 billion in 2100.

In the second scenario, called the Giant Leap, the researchers estimate that the population will peak at 8.5 billion people around 2040 and decline to around 6 billion by the end of the century . This is achieved through unprecedented investment in poverty alleviation - particularly in education and health - along with an extraordinary shift in policies on food and energy security, inequality and gender equality. In this scenario, extreme poverty is eliminated within a generation (by 2060), with a marked impact on global demographic trends.

The authors argue that other prominent demographic projections often downplay rapid economic development.

“We know that the rapid economic development of low-income countries has a huge impact on fertility rates. Fertility rates decline as girls access education and women become economically empowered and have access to better healthcare,” says Per Espen Stoknes, Earth4All project manager and director of the Center for Sustainability at the School of Norwegian business.

High population does not destabilize the planet

The team also looked at the connection between population and the overreach of planetary boundaries, linked to Earth's carrying capacity. Contrary to popular myths, the team found that population size is not the main driver of exceeding planetary boundaries, like climate change. Rather, it is the sky-high levels of material footprint among the world's richest 10% that are destabilizing the planet.

“The main problem of humanity is the luxury consumption of carbon and biosphere, not the population. The places where populations are increasing the fastest have extremely small environmental footprints per person compared to places that peaked in population many decades ago,” said Jorgen Randers, one of Earth4All's lead modelers and co-author of The Limits to Growth.

According to the team's demographic projections, the entire population could achieve living conditions above the United Nations minimum level without significant changes in current development trends, provided resources were distributed equally.