In an article published in The Lancet medical journal earlier this week, experts now believe the global population will likely shrink from a mid-century peak, predicting not only major shifts in the global populace, but also in economic power. The prediction is for a steady decline in the total fertility rate (TFR) from 2.37 in 2017 to 1.66 in 2100, well below the minimum rate 2.1 considered necessary to maintain population numbers with rates plunging to around 1.2 in Italy and Spain, and as low as 1.17 in Poland. In the US, the TFR is predicted to steadily decline from 1.8 in 2017 to 1.5 in 2100. If the predictions are correct, globally the TFR will have plunged from 4.7 to 1.66 in only 150 years.
By the end of this century, the USA is forecasted to have the fourth largest working-age population in the world at around 181 million people, after India, Nigeria, and China, however, only with immigration sustaining the US workforce, with the largest net immigration in absolute numbers. Approximately half a million more people are estimated to immigrate into the USA in 2100 than will leave. However, the researchers warn that US liberal immigration policies have faced a political backlash in recent years (read Trump), threatening the country's potential to sustain population and economic growth.
As fertility rates fall and life expectancy rises globally, the number of children under 5 is forecasted to decline by 41% from 681 million in 2017 to just over 400 million in 2100, whilst the number of folks older than 80 years is projected to increase six fold, from 141 million to 866 million. Likewise, the ratio of the world’s adults over 80 years to each person aged 15 years or younger is predicted to rise from 0.16 in 2017 to 1.50 in 2100, in those countries with a population decline of more than 25%. Additionally, if labour force participation by age and sex stays in status quo, the global ratio of non-working adults to workers will increase to 1.16 in 2100 from around 0.8 in 2017.
The analysis stated that fertility rates in 183 of 195 countries will not be high enough to maintain current populations. The global population is forecasted to peak around 2064 at about 9.7bn people, then fall back to approximately 8.8bn by 2100 with 23 countries seeing populations shrink by more than 50%, including Thailand, Japan, Spain, and Italy. There will also be dramatic declines in working age-populations in countries such as China and India, which will hamper economic growth and lead to shifts in global powers.
The fall in fertility rates is being driven by improved access to modern contraception and the increased global education of girls and women.