WEDNESDAY, July 15, 2020 (HealthDay News) -- The global population is anticipated to peak in 2064 and then decline to year 2100, according to a study published online July 14 in The Lancet.
Stein Emil Vollset, Dr.P.H., from the University of Washington in Seattle, and colleagues modeled the future population in reference and alternative scenarios as a function of fertility, migration, and mortality rates using novel forecasting methods.
The researchers found that in the reference scenario, the global total fertility rate (TFR) was forecasted to be 1.66 in 2100. The global population was projected to peak at 9.73 billion people in 2064 and decline to 8.79 billion in 2100 in the reference scenario. For the five largest countries in 2100, the reference projections were 1.09 billion, 791 million, 732 million, 336 million, and 248 million for India, Nigeria, China, the United States, and Pakistan, respectively. A shifting age structure was suggested in many parts of the world; by 2100, 2.37 billion individuals older than 65 years and 1.70 billion younger than 20 years were forecast. A total of 151 and 183 countries were forecasted to have a TFR lower than the replacement level by 2050 and 2100, respectively. From 2017 to 2100, 23 countries were forecast to have population declines greater than 50 percent in the reference scenario.
"Global population is likely to peak well before the end of the century," the authors write. "Given that we forecasted that societies tend towards a TFR lower than 1.5, once global population decline begins, it will probably continue inexorably."