World population in 2100 could be 2 billion below UN projections
Earth will be home to 8.8 billion souls in 2100, 2 billion less than current UN projections, according to a significant study published Wednesday 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 -- could 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 almost that much, from 1.4 billion people today to 730 million in 80 years.
Sub-Saharan Africa, meanwhile, will triple in proportions to some3 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, in addition to significant economic chance for elements of sub-Saharan Africa," lead author Christopher Murray, director of the Institute for Health Metrics and Evaluation (IHME) at the University of Washington, told AFP.
"However, most countries beyond Africa will dsicover 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 financial growth will be flexible immigration policies and social support for families who want children, the analysis concluded.
"However, when confronted with declining population you will find a very real danger that some countries might consider policies that restrict access to reproductive health services, with potentially devastating consequences," Murray cautioned.
866 million people over 80
"It really is imperative that women's freedom and rights are at the top of every government's development agenda."
Social services and healthcare systems should be overhauled to support much older populations.
As fertility falls and life span increases worldwide, the quantity of children under five is forecast to decline by a lot more than 40%, from 681 million in 2017 to 401 million in 2100, the analysis found.
At the other end of the spectrum, 2.37 billion people -- greater than a quarter of the global population -- will be over 65 years old at that time.
Those over 80 will balloon from about 140 million today to 866 million.
Sharp declines in the number and proportion of the working-age population may also pose huge challenges in many countries.
"Societies will battle to grow with fewer personnel and taxpayers," noted Stein Emil Vollset, a professor at the IHME.
The number of people of working age in China, for instance, will plummet from about 950 million today to just over 350 million by the finish of the century -- a 62 percent drop.
The decline in India is projected to be less steep, from 762 to 578 million.
In Nigeria, by contrast, the active labour force will expand from 86 million today to a lot more than 450 million in 2100.
These tectonic shifts may also reshuffle the pecking order when it comes to economic clout, the researchers forecast.
A fresh multipolar world
By 2050, China's gross domestic product will overtake that of america, but fall back into second place by 2100, they predict.
India's GDP will rise to take the quantity three spot, while Japan, Germany, France and the UK will remain among the world's 10 major economies.
Brazil is projected to fall in ranking from eighth today to 13th, and Russia from the quantity 10 spot to 14th. Historical powers Italy and Spain, meanwhile, decline from the top 15 to 25th and 28th, respectively.
Indonesia could become the 12th greatest economy globally, while Nigeria -- currently 28th -- is projected to crack the top 10.
"By the finish of the century, the world will be multipolar, with India, Nigeria, China and america the dominant powers," said Richard Horton, describing the analysis as outlining "radical shifts in geopolitical power."
Until now, the US -- which forecasts 8.5, 9.7 and 10.9 billion persons in 2030, 2050 and 2100, respectively -- has almost had a monopoly in projecting global population.
The difference between the UN and IHME figures hinges crucially on fertility rates. The so-called "replacement rate" for a well balanced population is 2.1 births per woman.
UN calculations assume that countries with low fertility today will dsicover those rates increase, typically, to about 1.8 children per woman over time, said Murray.
"Our analysis shows that as women are more educated and have usage of reproductive health services, they want to have less than 1.5 children on average," he explained by email.
"Continued global population growth through the century is no longer the probably trajectory for the world's population."
Founded in 2007 and supported by the Bill and & Melinda Gates Foundation, the IHME had turn into a global reference for health statistics, especially its gross annual Global Burden of Disease reports.
