from
https://www.bloomberg.com/opinion/articles/2024-03-10/global-population-collapse-isn-t-sci-fi-anymore-niall-ferguson

Global Population Crash Isn't Sci-Fi Anymore
We used to worry about the planet getting too crowded, but there are
plenty of downsides to a shrinking humanity as well.

March 9, 2024 at 9:00 PM PST

By Niall Ferguson
Niall Ferguson is a Bloomberg Opinion columnist. He is the Milbank
Family Senior Fellow at the Hoover Institution at Stanford University
and the author, most recently, of “Doom: The Politics of Catastrophe.”

It’s getting lonely out there. Photographer: Greg Baker/AFP/Getty Images

We used to imagine humanity populating the universe. In Isaac Asimov's
Foundation (1952), mankind has established a vast multi-planetary empire
by the year 47000. “There were nearly twenty-five million inhabited
planets in the Galaxy,” Asimov wrote. “The population of Trantor [the
imperial capital] … was well in excess of forty billions.”

In Liu Cixin’s Three-Body Problem (2006), by contrast, we’re a cosmic
rounding error, bracing ourselves for the terrifying Trisolaran
invasion. As the trailer for the new Netflix series puts it: “They are
coming, and there is nothing you can do to stop them.”

BloombergOpinion
An (Almost) Inverted Yield Curve Is Worrying China
Beijing’s Pain Could Be Washington’s Gain
Trump’s Immigration Plan Would Revive America’s Dark Past
Now Biden Needs to Show His Moderate Side

When Asimov was born in 1920, the global population was around 1.9
billion. When he published Foundation, it was 2.64 billion. By the time
of his death in 1992, it was 5.5 billion, nearly three times what it had
been at his birth. Considering that there had been a mere 500 million
humans when Christopher Columbus landed on the New World, the
proliferation of the species homo sapiens in the modern era had been an
astonishing feat.

Small wonder some members of Asimov’s generation came to dread
overpopulation and fret about an impending Malthusian disaster. This led
to all kinds of efforts to promote contraception and abortion, as
described in Matt Connelly's Fatal Misconception: The Struggle to
Control World Population (2008). Among these was China’s one-child
policy, the harshest ever government intervention in human reproductive
behavior.

Superficially, these efforts were a complete failure. Frank Notestein,
the Princeton demographer who became the founding director of the United
Nations Population Division (UNPD), estimated in 1945 that the world’s
population would be 3.3 billion by the year 2000. In fact, it exceeded
6.1 billion. Today it is estimated to be more than 8 billion. In its
most recent projection, the UNPD’s median estimate is that the global
population will reach 10.4 billion by the mid 2080s, with an upper bound
of more than 12 billion by the end of the century.

Yet that seems rather a low-probability scenario. The European
Commission’s Centre of Expertise on Population and Migration projects
that the global population will peak at 9.8 billion in the 2070s.
According to the Institute for Health Metrics and Evaluation, an
independent research organization, it will peak at a lower level and
earlier still, at 9.7 billion in 2064.

The key word is “peak.” Nearly all demographers now appreciate that we
shall likely reach peak humanity this century. This is not because a
lethal pandemic will drive up mortality far more than Covid-19 did,
though that possibility should never be ruled out. Nor is it because the
UNPD incorporates into its population model any other apocalyptic
scenario, whether disastrous climate change or nuclear war.

It is simply because, all over the world, the total fertility rate (TFR)
— the number of live children the average woman bears in her lifetime —
has been falling since the 1970s. In one country after another, it has
dropped under the 2.1 threshold (the “replacement rate,” allowing for
childhood deaths and sex imbalances), below which the population is
bound to decline. This fertility slump is in many ways the most
remarkable trend of our era. And it is not only Elon Musk who worries
that “population collapse is potentially the greatest risk to the future
of civilization.”

Our species is not done multiplying, to be sure. But, to quote the UNPD,
“More than half of the projected increase in the global population
between 2022 and 2050 is expected to be concentrated in just eight
countries: the Democratic Republic of the Congo [DRC], Egypt, Ethiopia,
India, Nigeria, Pakistan, the Philippines and the United Republic of
Tanzania.” That is because already “close to half of the global
population lives in a country or area where lifetime fertility is below
2.1 births per woman.”

Not many people foresaw the global fertility collapse. Nor did just
about anyone expect it to happen everywhere. And I can’t a single pundit
predicting just how low it would go in some countries. In South Korea
the total fertility rate in 2023 is estimated to have been 0.72. In
Europe there is no longer a difference between Roman Catholic and
Protestant countries. Italy’s current TFR (1.21) is lower than England’s
(1.44). Nor is there a difference between Christian and Islamic
civilizations — those great historical entities whose clashes the
historian Samuel Huntington worried about. The US total fertility rate
is now 1.62. The figure for the Islamic Republic of Iran is 1.54.

Outside of Africa, a Shrinking Planet
Among selected countries, only Democratic Republic of Congo had a
birthrate above replacement level of 2.1 live births per woman in 2023

Source: United Nations Population Department

The timing of this huge demographic transition has varied, to be sure.
In the US, the TFR fell below 2.0 in 1973. In the UK, it happened a year
later; in Italy in 1977. The East Asian countries were not far behind:
In South Korea TFR was above 2.0 until 1984; in China until 1991.
Fertility remained higher for longer in the Muslim world, but it fell
below 2.0 in Iran as early as 2001. Even in India the TFR has now fallen
below 2.0.

Only in the countries of sub-Saharan Africa does fertility remain well
above the replacement rate. In the DRC, for example, the average woman
still bears more than 6 children. But there, too, fertility is expected
to plummet in the coming decades. The global TFR, according to the
UNPD’s medium-variant projection, will fall from 2.3 in 2021 to 1.8 in
2100. The differences in estimates of when we reach peak humanity
largely hinge on how quickly demographers think family size will shrink
in Africa.

A Global Baby Bust
Total fertility for selected countries, in average live births per woman

Source: United Nations Population Department

Note: Projections start in 2023

What are the drivers of the great fertility slump? One theory, according
to a thought-provoking 2006 paper by Wolfgang Lutz, Vegard Skirbekk and
Maria Rita Testa, is that “societies progress up the hierarchy of needs
from physical survival to emotional self-actualization, and as they do
so, rearing children gets short shrift because people pursue other, more
individualist aims. … People find other ways to find meaning in life.”
Another interpretation (see for example this paper by Ron Lesthaeghe)
gives the agency to women, emphasizing that fertility drops as female
education and employment rise.

Over the past century, beginning in Western Europe and North America, a
rising proportion of women have entered higher education and the skilled
labor force. Improved education has also given women greater autonomy
within relationships, a better understanding of contraception, and
greater input into family planning. Many have opted to delay becoming
mothers in order to pursue their careers. And the opportunity cost of
having children increases as women’s wages rise relative to their male
partners.

Another way of looking at the problem is that, after its initial
kids-in-cotton-mills phase, the industrial revolution reduced the
importance of children as a source of unskilled labor. As countries
develop economically, families invest more in their children, providing
them with better education, which increases the cost of raising each
individual child.

Cultural change has also played a part. One study estimated that roughly
a third of the decline in fertility in the US between 2007 and 2016 was
due to the decline in unintended births. My generation — the baby
boomers — were more impulsive and indeed reckless about sex. By
contrast, according to the psychologists Brooke Wells and Jean Twenge,
millennials have fewer sex partners on average than we did. A 2020
analysis of responses to the General Social Survey revealed higher rates
of sexual inactivity among the most recent cohort of 20- to 24-year-olds
than among their predecessors born in the 1970s and ‘80s. Between
2000-02 and 2016–18, the proportion of 18- to 24-year-old men who
reported having no sexual activity in the past year increased from 19%
to 31%.

The fact that the declines in sexual activity were most pronounced among
students and men with lower incomes and with part-time or no employment
suggests that declining sexual activity is economically determined.
However, other possible explanations include the “stress and busyness of
modern life,” the supply of “online entertainment that may compete with
sexual activity,” elevated rates of depression and anxiety among young
adults, the detrimental effect of smartphones on real-world human
interactions, and the lack of appeal to women of “hooking up.”