The Lancet: Dramatic declines in global fertility rates set to transform global population patterns by 2100
Published March 20, 2024
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By 2100, 97% of countries will have fertility rates
below what is needed to sustain their population size.
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Originally posted by The Lancet (link is external).
By 2050, over three-quarters (155 of 204) of countries
will not have high enough fertility rates to sustain population size over time;
this will increase to 97% of countries (198 of 204) by 2100.
Pronounced shifts in patterns of livebirths are also
predicted, with the share of the world’s livebirths nearly doubling in
low-income regions from 18% in 2021 to 35% in 2100; and sub-Saharan Africa
accounting for one in every two children born on the planet by 2100.
In low-income settings with higher fertility rates,
better access to contraceptives and female education will help reduce birth
rates, while in low-fertility, high-income economies, policies that support
parents and open immigration will be vital to maintain population size and
economic growth.
Authors warn that national governments must plan for
emerging threats to economies, food security, health, the environment, and
geopolitical security brought on by these demographic changes that are set to
transform the way we live.
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The world is approaching a low-fertility future.
Although by 2100 more than 97% of countries and territories will have fertility
rates below what is necessary to sustain population size over time,
comparatively high fertility rates in numerous low-income countries,
predominantly in Western and Eastern sub-Saharan Africa, will continue to drive
population increases in these locations throughout the century. This
“demographically divided world” will have enormous consequences for economies
and societies, according to a new study published in The Lancet.(link is
external)
The research presents estimates from the Global Burden
of Disease, Injuries, and Risk Factors Study (GBD) 2021—a global research
effort led by the Institute for Health Metrics and Evaluation (IHME) at the
University of Washington’s School of Medicine—for past, current, and future
global, regional, and national trends in fertility and livebirths. In general,
countries need to have a total fertility rate (TFR) of 2.1 children per person
who could give birth, to sustain long-term generational replacement of the
population. The TFR of a population is the average number of children that are
born to a female over a lifetime, assuming childbearing at current fertility
rates throughout the reproductive years.
Using novel methods for forecasting mortality,
fertility, key drivers of fertility (e.g., level of education, unmet need for
modern contraception, child mortality, and living in urban areas), and
livebirths, the researchers estimate that by 2050, 155 of 204 (76%) countries and
territories will be below the replacement level of fertility. The number of
countries and territories below replacement level is predicted to further
increase to 198 of 204 (97%) by 2100. This means that in these locations,
populations will shrink unless low fertility can be offset by ethical and
effective immigration. The extent of low fertility may also be mitigated in
part by policies that offer greater support for parents.
The new fertility forecasts underscore the enormous
challenges to economic growth in many middle- and high-income countries with a
dwindling workforce and the growing burden on health and social security
systems of an aging population.
“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.”
The new study also predicts huge shifts in the global
pattern of livebirths from higher- to lower-income countries. In 2021, 29% of
the world’s babies were born in sub-Saharan Africa; by 2100, this is projected
to rise to over half (54%) of all babies, emphasizing the urgency for
improvements in access to modern contraception and female education in these
countries.
“We are facing staggering social change through the
21st century,” said senior author Professor Stein Emil Vollset from IHME. “The
world will be simultaneously tackling a ‘baby boom’ in some countries and a ‘baby
bust’ in the others. As most of the world contends with the serious challenges
to the economic growth of a shrinking workforce and how to care for and pay for
aging populations, many of the most resource-limited countries in sub-Saharan
Africa will be grappling with how to support the youngest, fastest-growing
population on the planet in some of the most politically and economically
unstable, heat-stressed, and health system-strained places on earth.”
“The implications are immense,” said co-lead author and
Lead Research Scientist from IHME Dr. Natalia V. Bhattacharjee. “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. 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.”
Declining fertility worldwide – only six countries
with fertility rates above replacement level in 2100
The global TFR has more than halved over the past 70
years, from around five children for each female in 1950 to 2.2 children in
2021—with over half of all countries and territories (110 of 204) below the
population replacement level of 2.1 births per female as of 2021. This trend is
particularly worrying for places such as South Korea and Serbia where the rate
is less than 1.1 child for each female. But for many countries in sub-Saharan
Africa, fertility rates remain high—the TFR of the region is nearly twice the
global average, at four children per female in 2021. In Chad, the TFR of seven
births is the highest in the world.
Over the coming decades, global fertility is predicted
to decline even further, reaching a TFR of around 1.8 in 2050, and 1.6 in
2100—well below the replacement level. By 2100, only six of 204 countries and
territories (Samoa, Somalia, Tonga, Niger, Chad, and Tajikistan) are expected
to have fertility rates exceeding 2.1 births per female. In 13 countries,
including Bhutan, Bangladesh, Nepal, and Saudi Arabia, rates are even predicted
to fall below one child per female.
The TFR in Western Europe is predicted to be 1.44 in
2050, dropping to 1.37 in 2100, with Israel, Iceland, Denmark, France, and
Germany expected to have the highest fertility rates at between 2.09 and 1.40
at the end of the century. Rates are projected to be much lower across the rest
of Europe and parts of Asia.
Most of the world is transitioning into natural
population decline (when the number of deaths exceeds the number of
livebirths); just 26 countries are still projected to be growing in population
in 2100 as livebirths continue to outnumber deaths, including Angola, Zambia,
and Uganda [1].
“In many ways, tumbling fertility rates are a success
story, reflecting not only better, easily available contraception, but also
many women choosing to delay or have fewer children, as well as more
opportunities for education and employment,” said Vollset.
Dramatic shifts in the patterns of births – with more
than half of livebirths occurring in sub-Saharan Africa by 2100
In the coming decades, the majority of children will
be born in some of the most resource-limited regions of the world, with over
three-quarters (77%) of livebirths expected in low- and lower-middle-income
countries by the end of the century.
Fertility decline for many countries in sub-Saharan
Africa is occurring at a slower pace, and the region is expected to contribute
to over half (54%; around 40 million) of the world’s livebirths by 2100, up
from around 41% in 2050, and around a quarter (29%) in 2021.
Much of the anticipated decline in the global share of
livebirths will be in the six other super-regions—falling, for example, in
South Asia—from around 25% (32 million) in 2021 to 17% (19 million) in 2050 and
7% (5 million) in 2100—but is forecasted to rise modestly in North Africa and
the Middle East (from 9% in 2021 to 11% in 2100) and the high-income
super-region (8% to 10%).
“A large challenge for countries in sub-Saharan Africa
with the highest fertility is to manage risks associated with burgeoning
population growth or risk potential humanitarian catastrophe,” said co-lead
author and Acting Assistant Professor from IHME Dr. Austin E. Schumacher. “The
huge shift in numbers of births underscores the need to prioritize this region
in efforts to lessen the effects of climate change, improve health care
infrastructure, and continue to reduce child mortality rates, alongside actions
to eliminate extreme poverty and ensure that women’s reproductive rights,
family planning, and education for girls are top priorities for every
government.”
Solutions for a demographically divided world
“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,” said
Schumacher. “Time is of the essence, as current efforts to manage population
growth will likely only be felt after 2050.”
The analysis suggests that concerted efforts to
fast-track access to modern contraceptives and female education—the two key
drivers of fertility—could help accelerate declines in fertility and reduce
birth rates in higher-fertility nations. For example, in sub-Saharan Africa,
projections estimate that achieving the UN Sustainable Development Goals for
universal female education or universal unmet need for modern contraceptives by
2030 would each result in fertility rates of 2.3 births per woman in 2050
compared with around 2.7 births if these targets aren’t met.
In the highest-fertility countries, the gains could be
even greater. In Niger, for example, the total fertility rate is predicted to
be five children for each female in 2050. But if the target of universal
education were met by 2030, the rate is projected to decline to 2.7 children
per female in 2050, while meeting universal contraceptive needs could lower the
rate to 4.3 children.
“In many ways, tumbling fertility rates are a success
story, reflecting not only better, easily available contraception, but also
many women choosing to delay or have fewer children, as well as more
opportunities for education and employment.”
“While achieving both universal targets in all
locations by 2030 is likely beyond reach, it’s clear that tackling the
population explosion in higher-fertility countries depends greatly on
accelerating progress in education for girls and reproductive rights.” said
Schumacher.
The study also examined the potential impact that
pro-natal policies designed to provide financial support and care for children
and families could have on increasing fertility rates in countries with
below-replacement fertility. Based on existing information from countries that
have already implemented such policies, the findings suggest that while pro-natal
policies will not boost fertility rates up to replacement level, they may
prevent some countries from dropping to extremely low fertility levels (with
just 30 countries and territories below a TFR of 1.3 in 2100 if pro-natal
policies are implemented compared to 94 under the most likely scenario). It
will be important for low-fertility countries to implement a combination of
policies that support those who wish to have children and offer additional
benefits to society such as better quality of life and greater participation of
women in the workforce, alongside open immigration policies.
“There’s no silver bullet,” said Bhattacharjee.
“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.
Sub-Saharan African countries have a vital resource that aging societies are
losing—a youthful population.”
She continues, “There is very real concern that, in
the face of declining populations and no clear solutions, some countries might
justify more Draconian measures that limit reproductive rights. It is well
established that nations with strong women’s rights are more likely to have
better health outcomes and faster economic growth. It is imperative women’s
rights are promoted and protected and that women are supported in having the
number of children they wish and pursuing their careers.”
The authors note some important limitations, including
that while the study uses the best available data, predictions are constrained
by the quantity and quality of past data, which was especially limited during
the 2020–2021 pandemic period. They also note that past trends are not
predictive of what will happen in the future, and that these fertility
forecasts rely on accurately forecasting each of the potential drivers of
fertility into the future.
Writing in a linked Comment, Gitau Mburu, James
Kiarie, and Pascale Allotey, of the World Health Organization, who were not
involved in the study, said “Fertility is an issue that concerns multiple
stakeholders and disciplines. Scientific predictions and policy discourses are
essential as we all search for answers. Accurate communication will facilitate
better understanding of the issue and informed decisions. Declining TFRs will
challenge the global community and could prompt innovations that assist us in
achieving sustainable development in the long term.”
NOTES TO EDITORS
The labels have been added to this press release as
part of a project run by the Academy of Medical Sciences seeking to improve the
communication of evidence. For more information, please see:
http://www.sciencemediacentre.org/wp-content/uploads/2018/01/AMS-press-release-labelling-system-GUIDANCE.pdf(link
is external) if you have any questions or feedback, please contact The Lancet
press office pressoffice@lancet.com
The study was funded by the Bill & Melinda Gates
Foundation. The paper was conducted by the GBD 2021 Fertility and Forecasting
Collaborators and researchers at the University of Washington, Seattle, USA.
Quotes from Authors cannot be found in the text of the
Article but have been supplied for the press release. The Comment quote is
taken directly from the linked Comment.
[1] There is around a 30-year gap between the time
when TFR falls below the replacement level (2.1) and when the natural rate of
population increase turns negative (i.e., the number of deaths will exceed the
number of livebirths).
For interviews with Article authors, please email the
IHME media team at media@healthdata.org.
Tables: Total fertility rates in 2050 and 2100
Top 10 country fertility rates (worldwide - 2050)
1.
Niger (Western sub-Saharan Africa) 5.15
2.
Chad (Western sub-Saharan Africa) 4.81
3.
Somalia (Eastern sub-Saharan Africa) 4.30
4.
Mali (Western sub-Saharan Africa) 4.21
5.
South Sudan (Eastern sub-Saharan Africa) 4.09
6.
Burkina Faso (Western sub-Saharan Africa) 3.76
7.
Afghanistan (North Africa and Middle East) 3.34
8.
Samoa (Oceania) 3.18
9.
Benin (Western sub-Saharan Africa) 3.12
10.
Tonga (Oceania) 3.04
Top 10 country fertility rates (worldwide - 2100)
1.
Samoa (Oceania) 2.57
2.
Tonga (Oceania) 2.45
3.
Somalia (Eastern sub-Saharan Africa) 2.45
4.
Niger (Western sub-Saharan Africa) 2.24
5.
Chad (Western sub-Saharan Africa) 2.15
6.
Tajikistan (Central Asia) 2.13
7.
Israel (Western Europe) 2.09
8.
Egypt (North Africa and Middle East) 2.05
9.
Zimbabwe (Southern sub-Saharan Africa) 2.01
10.
South Sudan (Eastern sub-Saharan Africa) 1.98
Lowest 10 country fertility rates (worldwide) – 2050
1.
South Korea (High-income Asia Pacific) 0.82
2.
Puerto Rico (Caribbean) 0.84
3.
Taiwan (Province of China) (East Asia) 0.90
4.
Serbia (Central Europe) 1.01
5.
Ukraine (Eastern Europe) 1.01
6.
Andorra (Western Europe) 1.02
7.
Saint Lucia (Caribbean) 1.04
8.
Bhutan (South Asia) 1.07
9.
The Maldives (Southeast Asia) 1.07
10.
Kuwait (North Africa and Middle East) 1.07
Lowest 10 country fertility rates (worldwide) – 2100
1.
Bhutan (South Asia) 0.69
2.
The Maldives (Southeast Asia) 0.77
3.
Puerto Rico (Caribbean) 0.81
4.
Nepal (South Asia) 0.82
5.
South Korea (High-income Asia Pacific) 0.82
6.
Saint Lucia (Caribbean) 0.87
7.
Taiwan (province of China) (East Asia) 0.90
8.
Cabo Verde (Western sub-Saharan Africa) 0.91
9.
Djibouti (Eastern sub-Saharan Africa) 0.95
10.
Bosnia and Herzegovina (Central Europe) 0.95
