Three quarters of all countries will have shrinking populations by 2050: Study

By the end of the 21st century, the population of nearly every country will be shrinking, according to a new study released Wednesday. 

In half of all the world's countries, the fertility rate is already too low to maintain their population sizes, according to data collected by hundreds of international researchers and reported in The Lancet. By 2050, the population of three quarters of all countries will be shrinking, which will increase to 97% of countries by 2100. 

The information is an update to the Global Burden of Disease study by the US-based Institute For Health Metrics and Evaluation (IHME) set up at the University of Washington by the Bill and Melinda Gates Foundation. Researchers looked at global data on births, deaths and what drives fertility to forecast the future for the world's population. 

Researchers also predict a massive social change will happen as a result, since rich nations are expected to have fewer babies and developing nations are expected to see a bigger boom comparatively, according to the study.

The world's population is shrinking, according to researchers.  (iStock)

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Birth rates are expected to slow even in low-income settings that typically have higher fertility rates due to better access to contraceptives and female education, according to the data. In contrast, in low-fertility, high-income economies, policies that "support parents," as well as "open immigration" will be "vital" to maintaining population size and economic growth.

"There’s no silver bullet," co-lead author and Lead Research Scientist from IHME, Dr. Natalia V. Bhattacharjee, said, according to The Lancet. "Social policies to improve birth rates such as enhanced parental leave, free childcare, financial incentives, and extra employment rights, may provide a small boost to fertility rates, but most countries will remain below replacement levels."

"And once nearly every country’s population is shrinking, reliance on open immigration will become necessary to sustain economic growth," she added. "Sub-Saharan African countries have a vital resource that aging societies are losing—a youthful population."

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Co-lead author and Acting Assistant Professor from IHME, Dr. Austin E. Schumacher, warned The Lancet that "time is of the essence" in taking action, "as current efforts to manage population growth will likely only be felt after 2050."

Sub-Saharan Africa will account for one in every two children born on the planet by 2100.  (iStock)

"These profound changes in future fertility reveal a clear demographic divide between the impacts on many middle-to high-income nations versus many low-income locations that requires national governments to implement safe and beneficial policies to help support conditions that can increase birth rates in some regions and lower them in others," he said. 

Fertility rates are expected to increase in sub-Saharan Africa, accounting for one in every two children born on the planet by 2100. The only countries expected to have fertility rates higher than the replacement level of 2.1 births per female by the turn of the century are Samoa, Somalia, Tonga, Niger, Chad and Tajikistan. 

Bhattacharjee added that the implications of the predicted population change are "immense."

"These future trends in fertility rates and livebirths will completely reconfigure the global economy and the international balance of power and will necessitate reorganising societies," he said. "Global recognition of the challenges around migration and global aid networks are going to be all the more critical when there is fierce competition for migrants to sustain economic growth and as sub-Saharan Africa’s baby boom continues apace."

Kendall Tietz is a Production Assistant with Fox News Digital.