Study predicts 8.8b to inhabit earth in 2100

Earth will be home to 8.8 billion souls in 2100, 2 billion fewer than current UN projections, according to a major study published yesterday that foresees new global power alignments shaped by declining fertility rates and greying populations.

By century’s end, 183 of 195 countries — barring an influx of immigrants — will have fallen below the replacement threshold needed to maintain population levels, an international team of researchers reported in The Lancet. More than 20 countries, including Japan, Spain, Italy, Thailand, Portugal, South Korea and Poland, will see their numbers diminish by at least half.

China’s will fall nearly that much, from 1.4 billion people today to 730 million in 80 years.

Sub-Saharan Africa, meanwhile, will triple in size to some three billion people, with Nigeria alone expanding 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 significant economic opportunity for parts of sub-Saharan Africa,” lead author Christopher Murray, director of the Institute for Health Metrics and Evaluation at the University of Washington, said.

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

For high-income countries in this category, the best solutions for sustaining population levels and economic growth will be flexible immigration policies and social support for families who want children, the study concluded.

“However, in the face of 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,” Murray cautioned. “It is imperative that women’s freedom and rights are at the top of every government’s development agenda.”

Social services and health care systems will need to be overhauled to accommodate much older populations.

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.