World population in 2100 could be 2 billion below UN projections
More than 20 countries will see their numbers diminish by at least half.
According to a major study published by renowned medical journal The Lancet on Tuesday (14 July), Earth will be home to 8.8 billion people in the year 2100, two billion fewer than current UN projections.
The study, titled Fertility, mortality, migration, and population scenarios for 195 countries and territories from 2017 to 2100: A forecasting analysis for the Global Burden of Disease Study, came to that conclusion based on a combination of the impact of declining fertility and ageing populations.
It speculates that more than 20 countries – including Japan, Spain, Italy, Thailand, Portugal, South Korea and Poland – will see their population diminish by at least 50% by the end of the century.
China, the country with the highest population in the world, is expected to fall from 1.4 billion people to 730 million in the space of 80 years.
Across the world, the number of people over the age of 80 will increase from about 140 million now to 866 million, according to the study conducted by the University of Washington.
Lead author Christopher Murray, from the University of Washington, spoke about the effects of this potential change, saying: "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.
"However, most countries outside of Africa will see shrinking workforces and inverting population pyramids, which will have profound negative consequences for the economy."
The full report can be seen here.