World Population by 2100; UN Projections countered by IHME

By Rahul Vaimal, Associate Editor
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Global Population
Photo by San Fermin Pamplona from Pexels

A recent study published by an international team of researchers at the Institute for Health Metrics and Evaluation (IHME) on renowned medical journal weekly The Lancet suggests a tectonic shift in the global population within 2100. 

According to the report, the global population will reach 9.8 billion by 2100, which is 2 billion fewer than current UN projections leading to new global power alignments shaped by declining fertility rates and greying populations.

Key Findings 

By 2100, 183 of 195 countries unless they are highly influenced by a rush of immigrants, will fall below the required number of residents to maintain their population levels.

More than 20 countries including Japan, Spain, Italy, Thailand, Portugal, South Korea and Poland will only have 50% of their current population by 2100. While China, the most populous country in the world now, will only have 730 million people from 1.4 billion.

The greatest population burst is expected in Sub-Saharan Africa which will increase its population by 300% to reach three billion people. Nigeria alone will expand to almost 800 million in 2100, second only to India’s 1.1 billion.

“These forecasts suggest good news for the environment, with less stress on food production systems and lower carbon emissions, as well as a significant economic opportunity for parts of sub-Saharan Africa,” lead author Christopher Murray, Director of the Institute for Health Metrics and Evaluation (IHME) at the University of Washington.

“However, most countries outside of Africa will see shrinking workforces and inverting population pyramids, which will have profound negative consequences for the economy.”

The study suggested that high-income countries should opt for flexible immigration policies and social support for families who want children to sustain population levels and economic growth.

“However, in the face of the declining population there is a very real danger that some countries might consider policies that restrict access to reproductive health services, with potentially devastating consequences,” Mr. Murray warned.

More than 25% of the global population will be above 65 years

The study mentions that as fertility falls and life expectancy increases worldwide, the number of children under five is forecast to decline by more than 40 percent, from 681 million in 2017 to 401 million in 2100.

2.37 billion people, more than a quarter of the global population will be over 65 years old by 2100 with 866 million people being over 80 years.

“Societies will struggle to grow with fewer workers and taxpayers,” noted Stein Emil Vollset, a professor at the IHME.

The shrinking labor force 

The number of people of working age in China will plummet by 62 percent from about 950 million today to just over 350 million by the end of the century. The decline in India is projected to be less steep, from 762 to 578 million.

On the other hand, Nigeria will see it’s active labor force expand from 86 million today to more than 450 million in 2100.

These tectonic shifts will also reshuffle the pecking order in terms of economic clout, the researchers forecast.

New world order

The study projects that By 2050, China’s gross domestic product will overtake that of the United States only to fall back into second place by 2100. India’s GDP will rise to take the number three spot, while Japan, Germany, France and the UK will stay among the world’s 10 largest economies.

Brazil GP is projected to fall in ranking from eighth today to 13th, and Russia from the number 10 spot to 14th. Historical powers Italy and Spain meanwhile will decline from the top 15 to 25th and 28th, respectively.

“By the end of the century, the world will be multipolar, with India, Nigeria, China and the United States the dominant powers,” said Richard Horton, describing the study as outlining “radical shifts in geopolitical power.”

Populations Projections and Monopoly

Until now, the United Nations — which forecasts 8.5, 9.7 and 10.9 billion people in 2030, 2050 and 2100, respectively — has virtually had a monopoly in projecting the global population.

The difference between the UN and IHME figures hinges crucially on fertility rates. The so-called “replacement rate” for a stable population is 2.1 births per woman.

UN calculations assume that countries with low fertility today will see those rates increase, on average, to about 1.8 children per woman over time, said Murray.

“Our analysis suggests that as women become more educated and have access to reproductive health services, they choose to have less than 1.5 children on average,” he explained by email.

“Continued global population growth through the century is no longer the most likely trajectory for the world’s population.”

Institute for Health Metrics and Evaluation (IHME)

Founded in 2007 and supported by the Bill and & Melinda Gates Foundation, the IHME had become a global reference for health statistics, especially its annual Global Burden of Disease reports.

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