World population likely to
shrink after mid-century, forecasting major shifts in global population and
economic power
From The
Lancet
July 15, 2020 – With widespread,
sustained declines in fertility, the world population will likely peak in 2064
at around 9.7 billion, and then decline to about 8.8 billion by 2100 -- about 2
billion lower than some previous estimates, according to a new study.
Improvements in access to modern
contraception and the education of girls and women are generating widespread,
sustained declines in fertility, and world population will likely peak in 2064
at around 9.7 billion, and then decline to about 8.8 billion by 2100 -- about 2
billion lower than some previous estimates, according to a new study published
in The Lancet.
The modelling research uses data from
the Global Burden of Disease Study 2017 to project future global, regional, and
national population. Using novel methods for forecasting mortality, fertility,
and migration, the researchers from the Institute for Health Metrics and
Evaluation (IHME) at the University of Washington's School of Medicine estimate
that by 2100, 183 of 195 countries will have total fertility rates (TFR), which
represent the average number of children a woman delivers over her lifetime,
below replacement level of 2.1 births per woman. This means that in these
countries populations will decline unless low fertility is compensated by
immigration.
The new population forecasts contrast to
projections of 'continuing global growth' by the United Nations Population
Division, and highlight the huge challenges to economic growth of a shrinking
workforce, the high burden on health and social support systems of an aging
population, and the impact on global power linked to shifts in world
population.
The new study also predicts huge shifts
in the global age structure, with an estimated 2.37 billion individuals over 65
years globally in 2100, compared with 1.7 billion under 20 years, underscoring
the need for liberal immigration policies in countries with significantly
declining working age populations.
"Continued global population growth
through the century is no longer the most likely trajectory for the world's
population," says IHME Director Dr. Christopher Murray, who led the research.
"This study provides governments of all countries an opportunity to start
rethinking their policies on migration, workforces and economic development to
address the challenges presented by demographic change."
IHME Professor Stein Emil Vollset, first
author of the paper, continues, "The societal, economic, and geopolitical
power implications of our predictions are substantial. In particular, our
findings suggest that the decline in the numbers of working-age adults alone
will reduce GDP growth rates that could result in major shifts in global
economic power by the century's end. Responding to population decline is likely
to become an overriding policy concern in many nations, but must not compromise
efforts to enhance women's reproductive health or progress on women's
rights."
Dr Richard Horton,
Editor-in-Chief, The Lancet, adds: "This important research
charts a future we need to be planning for urgently. It offers a vision for
radical shifts in geopolitical power, challenges myths about immigration, and
underlines the importance of protecting and strengthening the sexual and
reproductive rights of women. The 21st century will see a revolution in the
story of our human civilisation. Africa and the Arab World will shape our
future, while Europe and Asia will recede in their influence. By the end of the
century, the world will be multipolar, with India, Nigeria, China, and the US
the dominant powers. This will truly be a new world, one we should be preparing
for today."
Accelerating decline in fertility worldwide
The global TFR is predicted to steadily
decline, from 2.37 in 2017 to 1.66 in 2100 -- well below the minimum rate (2.1)
considered necessary to maintain population numbers (replacement level) -- with
rates falling to around 1.2 in Italy and Spain, and as low as 1.17 in Poland.
Even slight changes in TFR translate
into large differences in population size in countries below the replacement
level -- increasing TFR by as little as 0.1 births per woman is equivalent to
around 500 million more individuals on the planet in 2100.
Much of the anticipated fertility
decline is predicted in high-fertility countries, particularly those in
sub-Saharan Africa where rates are expected to fall below the replacement level
for the first time -- from an average 4.6 births per woman in 2017 to just 1.7
by 2100. In Niger, where the fertility rate was the highest in the world in
2017 -- with women giving birth to an average of seven children -- the rate is
projected to decline to around 1.8 by 2100.
Nevertheless, the population of
sub-Saharan Africa is forecast to triple over the course of the century, from
an estimated 1.03 billion in 2017 to 3.07 billion in 2100 -- as death rates
decline and an increasing number of women enter reproductive age. North Africa
and the Middle East is the only other region predicted to have a larger
population in 2100 (978 million) than in 2017 (600 million).
Many of the fastest-shrinking
populations will be in Asia and central and eastern Europe. Populations are
expected to more than halve in 23 countries and territories, including Japan
(from around 128 million people in 2017 to 60 million in 2100), Thailand (71 to
35 million), Spain (46 to 23 million), Italy (61 to 31 million), Portugal (11
to 5 million), and South Korea (53 to 27 million). An additional 34 countries
are expected to have population declines of 25 to 50%, including China (1.4
billion in 2017 to 732 million in 2100; see table).
Huge shifts in global age structure --
with over 80s outnumbering under 5s two to one
As fertility falls and life expectancy
increases worldwide, the number of children under 5 years old is forecasted to
decline by 41% from 681 million in 2017 to 401 million in 2100, whilst the
number of individuals older than 80 years is projected to increase six fold, from
141 million to 866 million. Similarly, the global ratio of adults over 80 years
to each person aged 15 years or younger is projected to rise from 0.16 in 2017
to 1.50 in 2100, in countries with a population decline of more than 25%.
Furthermore, the global ratio of
non-working adults to workers was around 0.8 in 2017, but is projected to
increase to 1.16 in 2100 if labour force participation by age and sex does not
change.
"While population decline is
potentially good news for reducing carbon emissions and stress on food systems,
with more old people and fewer young people, economic challenges will arise as
societies struggle to grow with fewer workers and taxpayers, and countries'
abilities to generate the wealth needed to fund social support and health care
for the elderly are reduced," says Vollset.
Declining working-age populations could
see major shifts in size of economies
]The study also examined the economic
impact of fewer working-age adults for all countries in 2017. While China is
set to replace the USA in 2035 with the largest total gross domestic product
(GDP) globally, rapid population decline from 2050 onward will curtail economic
growth. As a result, the USA is expected to reclaim the top spot by 2098, if
immigration continues to sustain the US workforce.
Although numbers of working-age adults
in India are projected to fall from 762 million in 2017 to around 578 million
in 2100, it is expected to be one of the few -- if only -- major power in Asia
to protect its working-age population over the century. It is expected to
surpass China's workforce population (where numbers of workers are estimated to
decline from 950 million in 2017 to 357 million in 2100) -- rising up the GDP
rankings from 7th to 3rd.
Sub-Saharan Africa is likely to become
an increasingly powerful continent on the geopolitical stage as its population
rises. Nigeria is projected to be the only country among the world's 10 most
populated nations to see its working-age population grow over the course of the
century (from 86 million in 2017 to 458 million in 2100), supporting rapid
economic growth and its rise in GDP rankings from 23rd place in 2017 to 9th
place in 2100.
While the UK, Germany, and France are
expected to remain in the top 10 for largest GDP worldwide at the turn of the
century, Italy (from rank 9th in 2017 to 25th in 2100) and Spain (from 13th to
28th) are projected to fall down the rankings, reflecting much greater
population decline.
Liberal immigration could help sustain
population size and economic growth
The study also suggests that population
decline could be offset by immigration, with countries that promote liberal
immigration better able to maintain their population size and support economic
growth, even in the face of declining fertility rates.
The model predicts that some countries
with fertility lower than replacement level, such as the USA, Australia, and
Canada, will probably maintain their working-age populations through net
immigration (see appendix 2 section 4). Although the authors note that there is
considerable uncertainty about these future trends.
"For high-income countries with
below-replacement fertility rates, the best solutions for sustaining current
population levels, economic growth, and geopolitical security are open
immigration policies and social policies supportive of families having their
desired number of children," Murray says. "However, a very real
danger exists that, in the face of declining population, some countries might
consider policies that restrict access to reproductive health services, with
potentially devastating consequences. It is imperative that women's freedom and
rights are at the top of every government's development agenda."
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. They also
note that past trends are not always predictive of what will happen in the
future, and that some factors not included in the model could change the pace
of fertility, mortality, or migration. For example, the COVID-19 pandemic has
affected local and national health systems throughout the world, and caused
over half a million deaths. However, the authors believe the excess deaths
caused by the pandemic are unlikely to significantly alter longer term
forecasting trends of global population.
Writing in a linked Comment, Professor
Ibrahim Abubakar, University College London (UCL), UK, and Chair of Lancet
Migration (who was not involved in the study), says: "Migration can be a
potential solution to the predicted shortage of working-age populations. While
demographers continue to debate the long-term implications of migration as a
remedy for declining TFR, for it to be successful, we need a fundamental
rethink of global politics. Greater multilateralism and a new global leadership
should enable both migrant sending and migrant-receiving countries to benefit,
while protecting the rights of individuals. Nations would need to cooperate at
levels that have eluded us to date to strategically support and fund the
development of excess skilled human capital in countries that are a source of
migrants. An equitable change in global migration policy will need the voice of
rich and poor countries. The projected changes in the sizes of national
economies and the consequent change in military power might force these
discussions."
He adds: "Ultimately, if Murray and
colleagues' predictions are even half accurate, migration will become a
necessity for all nations and not an option. The positive impacts of migration
on health and economies are known globally. The choice that we face is whether
we improve health and wealth by allowing planned population movement or if we
end up with an underclass of imported labour and unstable societies. The Anthropocene
has created many challenges such as climate change and greater global
migration. The distribution of working-age populations will be crucial to
whether humanity prospers or withers."
The study was in part funded by the Bill
& Melinda Gates Foundation. It was conducted by researchers at the
University of Washington, Seattle, USA.
No comments:
Post a Comment