9 October 2025. Population | Worldbuilding
Once the world’s population starts to decline, it will keep on falling // ‘No snitching, no pigs, no corpos’: living the biopunk life. [J2T #651]
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1: Once the world’s population starts to decline, it will keep on falling
Doing some demographics work for a client, I went back to an extract from a book, After The Spike, by the American economic demographers Dean Spears and Michael Geruso. It was on LitHub, which isn’t my usual go-to place for population research.
The article comes with a compelling graphic, showing global population over 8,000 years. And it looks like this—the “spike” of the book title.
Source: After The Spike
The data to the left of the dot is actual, if estimated, data, the line to the right is projected. And of course, all projected population data is largely dependent on your assumptions about fertility rates. This projection assumes a fertility rate of 1.6. This might seem low—replacement population rate is 2.1. But it’s the current fertility rate in the United States, which is not at the low end of current global fertility rates.
It seems that peak year for global births was in 2012, when 146 million were children were born worldwide. It has been falling steadily since.
But this is also a long-term trend:
The fall in global birth rates has lasted centuries. It began before modern contraception and endured through temporary blips like the post-World War II baby boom. For as far back as there are data to document it, the global birth rate has fallen downward—unsteadily, unevenly, but ever downward. So far, falling birth rates have merely slowed the growth in humanity’s numbers. So far.
At the moment, global population is continuing to grow, because the number of births still outstrips the number of deaths. That won’t last, and we will reach peak global population within a few decades. The only thing that divides demographers is how quickly this will happen.
The demographers at the UN believe it is most likely to happen in the 2080s. The experts at the International Institute for Applied Systems Analysis in Austria place the peak a little sooner in the same decade. The Institute for Health Metrics and Evaluation at the University of Washington projects a peak even sooner, in the 2060s.
Spears and Geruso are interested in what happens after this moment, whenever it comes. And the speed of the decline is striking:
We do not mean that humanity would stop growing, reach some plateau, and stabilize near our present numbers. Every decade after turning the corner, there would be fewer of us. Within three hundred years, a peak population of 10 billion could fall below 2 billion.
To get to this projection, the researchers haven’t made any outlandish assumptions. They have projected the current global fertility levels forwards:
The birth rate is below two in Mexico, Canada, Brazil, Russia, Thailand, and many other countries. The European Union as a whole is at 1.5. The two most populous countries, India and China, are both below two. A birth rate below two is found within each U.S. state; when looking only among U.S. Blacks, whites, or Hispanics; and in every Canadian province.
The piece tells some of this story anecdotally, through the eyes of a rural Indian woman called Preeti. They have chosen India because it is
India is in the middle of the world’s statistics: middle in income, middle in life expectancy, and middle in birth rates.
It’s also the world’s most populous country. What happens in India shapes what happens elsewhere. And it turns out that Preeti would like to have two children, and she’s not exceptional in this.
[E]ven back in 2020, those who had been to secondary school (a growing fraction of girls and women in India) averaged 1.8, which matches the average for all U.S. women in 2016. The hospital where Preeti gave birth is in an especially disadvantaged state of India. But young women there said that they want about 1.9 children, on average.
(Photo by rajat sarki on Unsplash)
What young women say matters here. I wrote about this here about a year ago, and the research suggests that what women say about the size of family they want is the best single predictor of family size.
It’s worth noting that relatively small changes in the distribution of children within families makes quite a big difference to the outcomes.
Source: After The Spike
On the left, a depopulation mix; on the right, a stabilisation mix. The difference is a relatively small shift from some women having less than two children to some having more.
Of course, as the futurist Ged Davis once remarked, “A trend is a trend is a trend until it bends.”
And you can’t look at this projection—even prediction—without considering the possibility that fertility levels might increase again, and climb past 2.1.
Version 1 of this is whether we might just see enough of a change to represent an uptick. They think this unlikely, partly because the long decline in fertility is long—it’s been going on for several hundred years.
More specifically, and looking at more recent data:
Since 1950, there have been twenty-six countries, among those with good enough statistics to know, where the number of births has ever fallen below 1.9 births in the average woman’s full childbearing lifetime... A 0-for-26 record does not mean that things couldn’t change, but it would be reckless to ignore the data.
We also know that a number of governments with a commitment to ideas of the “traditional family” have thrown all sorts of incentives at people to try to increase fertility rates, with no success.
If a reversal happens, it will be because people decided they wanted to reverse it and then worked to make it happen, not because automatic stabilizers kicked in.
Spears and Geruso give do some consideration to the idea that people might have larger families in the future for the same reason that they did in the past—as a form of social insurance. But that also implies that some kind of disaster might have happened in the meantime, which will also have reduced the population.
In general, then, they think it’s much more likely that global population will decline after it has peaked, rather than stabilising at some lower level. This is because any kind of stabilisation implies an increase in fertility levels in the absence of a shock.
Usually this is discussed in terms of economics—even at the simple level of social care, our economies are built on growing populations, not shrinking ones. But the cultural effects seem likely to be more profound. As a species, we only started living in countries with ageing populations a couple of decades ago, and already we seem to have politics dominated by the interests of the elderly. My client was a children’s charity, and on the other hand, if families are choosing to have fewer children, children will be given much more attention. This seems quite a destabilising dynamic.
2: ‘No snitching, no pigs, no corpos.’
Ian Green’s book Extremophile is a sustained exercise in world-building. It’s set in a future Britain - time undefined, but it feels as if it is sometime in the second half of the 21st century. Climate change has got worse—‘stopping Hull from flooding 15 years ago “wasn’t economically sensible”’—and neoliberalism has morphed into a full blown corporate state.
For Green, this is something of a departure, since he’s best known for his The Gauntlet trilogy of fantasy novels. The world he describes here is best described, I think, as ‘biopunk’: people can do, and do do, all sorts of physical and biological manipulation, and not always with the consent of the people involved, which as it turns out is quite an important plot point. But write what you know, as the saying goes, because it turns out that Green has a Ph.D. in clinical epigenetics, so he’s able to write about the biohacking at the heart of the story with some expertise.
For the purposes of Just Two Things, I’m more interested in the world building aspects than lit crit. But from the point of view of a reader, I should say than once I got my head into the story, and the bits of plot are done that are needed to get the characters into one place, it is a page turner, and that the narrative surprises--there are a few--make sense in the context of the story. But there won’t be any spoilers here.
(H/t, incidentally, to Paul Raven, who recommended the book on his blog months ago.)
Let me, instead, sketch out the world. Climate change has got worse, and governments have shrunk. To the extent that government works at all, it works in the service of a collection of anonymous corporations whose interests are protected by aggressive intellectual property legislation and their own privately maintained police forces. In the countryside, many people live in ‘corpo-towns’ maintained by the corporations. (For those outside of their protection, ‘corpo’ is a term of disdain, or abuse.) There’s a large active underclass that looks after itself outside of the mainstream economy, living in places that are in a kind of liminal space, a nomansland, between city and country. Violence is never far below the surface.
AI manages a lot of services, and security, and confusing it about who you are as you go across town is an important part of surviving in this world.
These outsiders have some well protected autonomous spaces in the city--the social life in the thriving and heaving semi-legal space below Smithfield’s Meat Market is lovingly detailed and becomes an important plot point later in the story. In that space ‘party rules’ apply:
no snitching, no pigs, no corpos, and don’t be a c*nt.
In this grim future, politics comes colour coded:
The punks and the kids say you are Green or Blue or Black. Greens want to save the world - go to the marches, make your own toothpaste. There are hard Greens (direct action, like the Heavy Crew with their hammer and sword) and soft Greens (grind your own quinoa, lament the death of the theatre). Blues don’t give a f*ck as long as there is profit - the sea will rise, but if you’ve got money there is always higher ground. Blacks know that the world is f*cked and you need to either have a good time or find a bath and a toaster.
(The asterisks are mine, by the way: being cautious about web filters.)
Into the middle of all of this, Ian Green pitches Charlie and Parker, who get by in the same way as everyone else in this world--by hustling, sometimes around the edges of the law. Parker runs a well-dodgy website that dispenses astrology, while Charile is an accomplished biohacker, which sometimes brings its own problems, from clients who haven’t quite got the upgrade they were expecting. But there’s definitely money in this, because in this future world, everyone is augmented. An ‘extremophile’ is defined in an epigraph as
Noun. BIOLOGY - an organism that thrives in extreme environments.
This all makes sense, and it also makes sense that the music scene that Charlie and Parker are part of is a kind of DIY electro-thrash scene where the performers of the music are also the fans, and gigs and events are impromptu and more or less shared by word of mouth, like a cross between 1975-era punk and early electro. Charlie and Parker (yes, I think I can see what Green might have doen there) met at a gig and now play together in a band called HORSE THEORY.
‘Mantra: PHILOSOPHY, says an epigraph. ‘When the horse you are riding dies, get off it.’
A world with this much inequality is going to have some eco-terrorists, and the eco-terrorists here are magnificent.
The Heavy Crew. The hardest of the hard Greens... The team who took the climate movement’s mantra of non-violence, looked at the world around them, and said hey, f*ck that. The Heavy Crew who sank four whalers with drones off the coast of Norway, the Heavy Crew who f*cked the Magnus pipeline with a decade of pipe bombs. The Heavy Crew who burned every luxury car in Berlin in a single night.
And for various reasons, Charlie and Parker, and some of their friends, are hired for a job by The Heavy Crew because they have some particular skills when it comes to disruption. The brief for the job is simple enough:
Kill the Ghost, steal a flower, save the world.
It sounds easy enough, but the Ghost is the head of AETOS DIOS, a notorious bio-manipulation company, with no ethical limits. The flower is the intellectual property of one of the heavily guarded corpos. The saving the world bit is easier. And then the plot kicks in. And it’s a roller coaster.
From a worldbuilding point of view, the reason the world works is because of the detail that surrounds it. Just one example of that here: what you need to do in practice not to be tracked by the city security AI:
So we’re on the Overground and only one change to Highbury and Islington on spoofed IDs, facemasks pulled up as if the smog/pollen/bird flu was a worry, walking with shitty pseudo limps with our ID-matched insoles. Everything is run by the transport Als, of course - no ticket inspectors, just linked systems tagging where you start and end, what you get up to in between. As soon as you get within a few hundred feet of a Tube station it’ll clock you (long before, if you are in Zone 1 where the infrastructure is more reliable)...
Skip a fare or try and cheat it and the Al will track you to the ends of the earth, but we don’t do that. The spoofed IDs are linked to prepaid travel cards. Only commit one crime at a time, my dad used to say.
Other writing: Salut Folk
I write about folk music for a modest music site, and that used to struggle by on Typepad, mostly because although Typepad was visibly dying on its feet from lack of investment, it was a lot of hassle to move it. But Typepad was abruptly closed with a few weeks notice at the end of September, and so we ended up shifting it—and its 18 year back catalogue—to Wordpress, now re-launched there as Salut Folk.
The flexibility of Wordpress means that we’ve been able to give the site more of a magazine feel, and the particular template we’re using lets us show some of the back catalogue as well. One of my recent pieces there was about the great British bass player Danny Thompson, who had been the backline for countless British folk musicians, from Pentangle to John Martyn to Martin Simpson, while continuing to play jazz, his first love, and experiment with world musics as well. (Thompson died at the end of September.) And since it’s the weekend, here’s Thompson playing with Martin Simpson.
j2t#651
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