The Population Bomb Revisited
Are there too many of us now? Will there be too few in the future?
Population is a Hot Topic Again
A surprising set of op-eds on the “baby bust” set me thinking about two books recently read with friends through our book club, and then searching the shelves for two older classics focused on human numbers. Taken together, these present a wide range of perspectives on population. How can we sort through these different points of view? To begin, here is an overview of those sources
While many pundits worry about possible social and economic disruptions that might result from declining birth rates, the op-eds that got me started on this essay take this concern to a new level. They revive and moralize on an old term, Anti-Natalism, and consider the baby bust a serious social threat.
The two classics sounded the opposite alarm. Paul Ehrlich’s The Population Bomb, and The Club of Rome’s The Limits to Growth took very different approaches, but both agreed that the exponential growth in population happening in the 1960s and 1970s was unsustainable.
The first book club title was Factfulness by Hans Rosling and others. It presented quite graphically the wide range in standard of living in different countries around the world, and how few live at the highest level. The second was Juan Du’s The Shenzhen Experiment on the causes and impacts of rapid urbanization and industrialization in China during an era that included the one child policy that will shape Chinese demographics for the rest of the century.
So where are we in terms of human numbers and well-being on the Earth now and in the future?
Family size, lifestyle, personal choice, and all the other factors affecting the topic of population make this a hot-button and easily politicized topic. But this is a science site, so before treading too closely to the edge of politics and policy, let’s start with some numbers and put them in the context of older theories and traditional demographics.
The Baby Bust and Population Trends
The baby bust is definitely real, although that name immediately puts a negative spin on it. Birth rates are falling everywhere, have been for decades, and are below replacement (two children born per woman) in many countries.
As birth rates continue to fall, population is projected to peak sometime in this century. Most estimates predict a maximum of 10-11 billion people between 2060 and 2080. Demographics is an incredibly complicated field, but in the last essay posted here, even a simple statistical extension of the current rate of decline in birth rates led to a predicted peak population of just under 10 billion around 2060.
Declining birth rates and peak populations reflect a complex social phenomenon that approaches the status of a physical law: the demographic transition. This is a nearly universal pattern of declining death rates followed by declining birth rates over time, driven by technological, economic, and social change, leading to a relatively stable number. Most discussions of this transition highlight the critical importance of the educational and social status of women.
Malthusians and Cornucopians
The demographic transition was not on the horizon when Thomas Malthus penned his eponymous theory. In 1798 he proposed that human population must necessarily outstrip the capacity of the Earth to feed us all and that starvation and famine would lead to plagues, war, and social chaos that together would set the upper limit on human numbers.
In the second half of the 19th century, he seemed to be right, as only natural fertilizers were available for agriculture, and food production was not keeping pace with population, even in wealthier countries like Malthus’ England.
If Malthusians see only disaster ahead, Cornucopians argue that whatever challenges we face, human ingenuity will find a solution – that there are no limits.
In the 20th century, first the invention of the Haber-Bosch process for producing nitrogen fertilizer and then the green revolution that matched fertilizer, irrigation, and improved practices with high-yield varieties of grains were classic Cornucopian events. Global grain yield per acre in some developing countries increased three-fold from 1960 to 2015, and even India, with a history of recurring famines, produced surpluses for export – at least temporarily.
These two innovations, along with many others, now support a population of 8 billion. It is argued that without them, 4 billion would have been the Malthusian maximum.
Whether this has been good or bad for the Earth is too complex a question for such a short essay, but score two for the Cornucopians.
Population and Famine
Famine has stalked humanity throughout our history. One source lists more than 75 events even after the invention of the Haber-Bosch process in the early 1900s. Documenting famine is a difficult task as reports are often suppressed in the affected country, and losses due to malnutrition are even more difficult to quantify, as they are often recorded as disease-related.
While weather and plant diseases play a role in famine, the largest events appear to be triggered by failed social policies – or war and social chaos - as Malthus might predict.
The Irish tragedy of the 1840s and 1850s was one of the most severe in terms of the fraction of the total population affected with perhaps 1 million out of 8 dead, and another 2 million+ forced to emigrate. This famine can be laid, at least partially, at the feet of a callous disregard for distribution of food surpluses according to need.
China has been particularly hard hit by famine with 7 events and perhaps 100 million deaths since 1876. The largest documented famine ever recorded occurred in China during the Great Leap Forward from 1958-1962, with estimates as high as 55 million lost to starvation.
Juan Du’s book credits Deng Xiaoping with leading and driving the rapid cultural change fostered by urbanization and industrialization, and stresses that he was motivated in large part by the desire to end the cycle of famine in the country. The one-child policy was initiated in 1984 as part of this set of policies. Harsh and controversial measures were used in its enforcement, but a discussion of those is best left to other venues.
On our topic, the outcome was a very rapid drop in births in China, and, by 2020, nearly zero population growth. As this small generation passes through their reproductive years, the population of the country might decline by as much as 300 million. The policy was abandoned in 2010, but birth rates continue to decline and current efforts by the government to increase family size have been largely unsuccessful.
The Classic Books and the Pro-Natalists
Authors of those two classic books mentioned above would see the current, largely voluntary (one child policy excepted) “baby bust” as a very positive and unexpected development.
Ehrlich, writing in the mid-1960s, basically said that it was all over - that we couldn’t feed the world even then, and that by 1980 or so, mass starvation, famine, disease, social chaos, and warfare would be the world’s lot. Massive pollution of air and water (DDT, smog, fertilizer runoff, etc.) would lead to shortened life spans and greatly reduced quality of life, and disaster would strike both the developed and “underdeveloped” worlds. His very Malthusian view saw no role for technological innovation to solve any of these problems.
The Club of Rome took a very different tack. Limits to Growth (and follow-on volumes) integrated population, resources, pollution, and economic well-being into a model that projected a peak in population sometime in the 21st century, followed by a decline driven by falling standards of living and quality of life. Their most optimistic scenarios began with stabilization of population and then added investments in resource reuse and pollution reduction to maintain sustainability.
However different their methods, both of these sources emphasized the unsustainable nature of continued population growth.
On the other hand, while several reputable sources describe the possible economic, labor and lifestyle disruptions that might accompany a continuing decline in birth rate, some see it as a serious existential threat.
I had not heard the term “Anti-Natalist” before, although it has a long history. A recent summary describes adherents as believing that human (or even animal) reproduction is bad or immoral, as life entails misery and eventual death.
There is now a “Pro-Natalists” camp that extends the Anti-Natalist label well beyond its historical meaning to anyone who wants to have 2 or fewer children. “Workism” is a newly coined, pejorative term applied by Pro-Natalists to those who find satisfaction primarily in their careers. Lifestyle choices that may lead to the formation of non-conventional families with few or no children are the target for these writers.
And this is not a judgement-free zone. Much like the Chinese one child policy, the goal seems to be to put social goals ahead of personal choice in terms of family formation.
What To Make of All This
Beyond political philosophy, all sources agree that any actual decline in total human numbers is decades away. Even one “Pro” writer noted that there will be more than 8 billion of us well beyond 2100, and that number might fall to 2 billion only as much as 300 years from now. Hard to predict what the world will be like in 2300.
Ehrlich’s Malthusian predictions have not come true yet, and the Club of Rome’s most optimistic scenarios seem to be the path we are on – so far, but neither would see stable to declining human numbers as a negative.
Caring for a larger, aging generation seems to be the most humanitarian concern on the list of baby-bust writers, but I wonder if there is an under-appreciation here of the effort and expense that goes into raising children. Perhaps with more small and alternative families, there might be more time and resources available to respond to the needs of that older generation, not less.
So perhaps there are more pressing issues than a possible decline in human numbers by 2300. We might put preparing coastal cities for rising sea levels, or feeding 10+ billion people in 2080 higher on the list of priorities.
Finally, we might focus some of this discussion on the fact that the vast majority of people in the world today live well below the standards of the developed countries, and that there is no way we can provide that level of well-being for 10 or even 8 billion people. The Roslings make this point very clearly in Factfulness.
A more equitable distribution of wealth, a higher general standard of living, and a reduction in the human footprint on the Earth and its climate system might all be more achievable with either a stable or slowly declining population.
And, given the ubiquitous nature of the demographic transition, maybe a stable population is just the logical and expected outcome when men, and especially women, have the economic and social support that allows them to choose how they will form and grow their families.
Sources
A shoutout first to the PALS book club for stimulating discussions and new sources, including:
Rosling, H., A. Ronnlund and O. Rosling. 2018. Factfulness. Flatiron Books.
Du, J. 2020. The Shenzhen Experiment. ProQuest Ebook Central.
The two classic books are:
Ehrlich, Paul. 1968. The Population Bomb. Ballantine Books, and
Meadows, D, D. Meadows, J. Randers and W. Behrens. 1972. The Limits to Growth. Universe Books.
The follow-ons include Meadows, D, D. Meadows, J. Randers. 1992. Beyond the Limits. Chelsea Green Publishing Company
Recent articles from conventional sources on the drop in birth rates include:
https://www.brookings.edu/articles/us-births-are-down-again-after-the-covid-baby-bust-and-rebound/
https://www.nytimes.com/interactive/2023/12/30/upshot/2023-year-in-review.html
Two recent analyses on demographic trends from the Pew Foundation are:
Some background on pro- and anti-natalism can be found here:
https://en.wikipedia.org/wiki/Antinatalism
https://en.wikipedia.org/wiki/Natalism
Some recent writings on Anti-Natalism:
https://www.nytimes.com/2024/01/31/opinion/birth-rates-baby-bust.html
https://www.nytimes.com/2024/02/02/opinion/anti-natalism.html
That this is currently a hot topic can be substantiated with a web search using either pro- or anti-natalism as key words.
The figure on change in total fertility rate was redrawn from:
https://commons.wikimedia.org/wiki/File:Total_Fertility_Rate_for_6_Regions_and_the_World,_1950-2100,_UN2022.svg Licensed under Creative Commons
Data by country and region from 1960 on can be found here:
https://data.worldbank.org/indicator/SP.DYN.TFRT.IN
Figure on future human numbers is modified from
https://ourworldindata.org/population-growth
see also:
https://en.wikipedia.org/wiki/Population_growth
The figure on the demographic transition is modified from:
https://upload.wikimedia.org/wikipedia/commons/8/8c/Demographic-TransitionOWID.png Licensed under Creative Commons
The web page on this topic is:
https://en.wikipedia.org/wiki/Demographic_transition
Information on the Green Revolution and estimates of population supportable without nitrogen fertilizers are included here:
https://en.wikipedia.org/wiki/Green_Revolution
The figure on numbers supportable with and without nitrogen fertilizers is from:
https://ourworldindata.org/grapher/world-population-supported-by-synthetic-nitrogen-fertilizers Licensed through Creative Commons
Data on famine fatalities are extracted from:
https://en.wikipedia.org/wiki/List_of_famines
and more background information is here:
https://en.wikipedia.org/wiki/Famine
More on the Chinese famine During the Great Leap Forward can be found here:
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1127087/
Background on the Irish Famine is here:
https://en.wikipedia.org/wiki/Great_Famine_(Ireland)
The graph on birthrates in China is here:
https://en.wikipedia.org/wiki/One-child_policy#/media/File:Birth_rate_in_China.svg Licensed through Creative Commons