Overpopulation

A common and urgent theme of twentieth century science fiction was concern over the rapid population growth of the human population. Narratives of overpopulation, and its impacts on family, society and humanity, abound. Here I take a look at these stories and consider how such concerns have propagated into the twenty-first century.

Population Pressure

Overpopulation came to the foreground in the dystopian New Wave novels of the late 1960s. Prominent amongst these were Make Room! Make Room! and Stand on Zanzibar, both of which focussed on the everyday trials and struggle for existence through vignettes of large casts of characters living in overcrowded cities.

Harry Harrison’s dystopian novel Make Room! Make Room! (novel, 1966) tells of a vastly overpopulated New York, in which the population are fed on soy-and-lentil steaks, and queue in line for water rations. Disorder and racketeering are rife, while multiple families share single room apartments. John Brunner’s Stand on Zanzibar (novel, 1967) also focussed on an overcrowded America, although it also addressed America’s relationship with Africa and south-east Asia in a projected 2010. Brunner’s United States is one in which capitalism is still the driving force, with major companies such as General Technics directed by decision-making computers. Eugenics boards get to decide the fitness of the few who are permitted to breed, and crowd pressure drives indiscriminate massacres when sanity snaps.

While Harrison and Brunner focussed on cityscapes and presenting many disparate viewpoints, the horizons in My Petition for More Space by John Hersey (novel, 1974 [1]) are much smaller. This is a short but haunting novel which is set entirely within a four-people wide but very long line of those waiting to present petitions to government, and in the petition hall. Throughout the long wait, the protagonist, Samuel Poynter, is forced to keep his world painfully narrow for the sake of sanity, forcing himself to concentrate only on his “touchers”: the attractive woman pressed against his front, the man against his back, and the two people to either side. Gradually, his world is forced to encompass the touchers of his touchers, but at the risk of an infectious sense of being overwhelmed. After waiting in line for four hours, the pressure of humanity around Poynter is palpable:

And all the while, fragmentary images of waiting humanity enter my distracted brain. I see a wart, a wen, a blackened tooth, a bent nose and a blue lip, a roll of fat at the back of a neck, a hairy ear, a satin cheek, greedy eyes, a too-neat pair of dark braids, a balding crown, a sag in a jowl, a pain-line at the edge of a mouth, a dimple, crow’s-feet, and pink wriggling veins—scraps of hope, bits of revealed struggle, signs here and there that it is already too late.

The protagonist’s request is a simple one, but ultimately futile in the face of the vast pressures around him. This is a world so overpopulated that each adult is entitled to just twelve by eight feet of floor space in communal sleeping halls, delineated by taped lines on the floor. The only green space is walled off and accessible only to the city mayor, while the majority spent more time in lines than anywhere else. While petitions are heard, there is little indication that they are listened to, or that there is any scope for change if they were.

Similar pressures for space drove a fiction of high population density megastructures, extending vertically into the sky, or below ground, as in High Rise by J G Ballard (novel, 1975), The World Inside by Robert Silverberg (novel, 1971) or Caves of Steel by Isaac Asimov (novel, 1953). Indeed such city-sized buildings became a ubiquitous feature of near-future cityscapes. Those cities themselves become nightmarish urban jungles, as in stories such as Robert Scheckley’s The People Trap (short story, 1955), Richard Wilson’s The Eight Billion (short story, 1965) or Rick Raphael’s Guttersnipe (short story, 1964).

A different but equally claustrophobic expression of such pressures can be found in the 1961 short story Tomorrow and Tomorrow and Tomorrow by Kurt Vonnegut [2]. This describes a world in which overpopulation is being driven not just by unlimited reproduction but also by development of an anti-aging treatment or anti-gerasone. While cities have expanded, they haven’t kept up. As a result, a small three-room apartment in New York houses not only 172 year old Harold Schwarz, known as Gramps, but all his descendants:

Emerald and Lou, coming in from the balcony, were obliged to take seats in the back row, behind Lou’s father and mother, brother and sister-in-law, son and daughter-in-law, grandson and wife, granddaughter and husband, great-grandson and wife and wife, nephew and wife, grandnephew and wife, great-grandniece and husband, great-grandnephew and wife, and, of course, Gramps, who was in front of everybody.

Gramps exercises tyranny over the entire clan, dictating sleeping and eating arrangements, and constantly shifting his favours and the promise of his inheritance. In an interesting and amusing twist, the entire family - with the exception of Gramps - is eventually arrested, finding themselves in a blissfully spacious prison, and Gramps is left in his still more spacious apartment, once more able to enjoy life.

Vonnegut was clearly interested in the topics of longevity and overpopulation, and its impact on society. Other short stories of his which explored the theme include 2 B R 0 2 B (1962) in which a person must volunteer to die before a birth is permitted, and Welcome to the Monkey House (1968) in which “ethical suicide” parlours are common and all adults take compulsory drugs that numb them from the waist down.

Make Room!

While many novels and stories have focussed on the state of humanity, and of human existence under such population pressures, a range of other writings, including films, have taken a more proactive approach and explored potential solutions to the overpopulation problem.

Echoing the theme of routine euthanasia in some of Vonnegut’s writing is Logan’s Run (film, 1976; dir. Anderson), which was based on a 1967 novel of the same name by William F Nolan and George Clayton Johnson. In both versions, human lifespan is limited by law - to 21 in the case of the novel and 30 for the film. The eponymous Logan is a Sandman, one of the enforcers tasked with tracking down “runners” - those who refuse to submit to their required suicide at the correct time. The ruthless Logan’s attitude gradually changes as he learns more of the runners’ beliefs and falls in love with a woman named Jessica.

In the film the reason for the enforced age-limit is the limited resources of a post-apocalyptic domed city, which forms a closed environment, and those reaching 30 are destroyed in an elaborate ritual known as Carrousel. However in the book, the rule results from massive overpopulation forming an inverted demographic, in which the vast majority of the world’s population are under twenty-one. A youth uprising, known as the Little War, places power in the hands of young people, and a quieter self-sacrificing movement which embraces euthanasia soon becomes law. Imposing the upper age limit has the twin effect of reducing the population directly and of reducing the number of fertile years available for reproduction, and so the number of births.

An equally horrifying solution to the population crisis is found in the film Soylent Green (1973; dir. Fleischer). This film was loosely based on Harrison’s novel Make Room! Make Room!, and takes its name from the soy-and-lentil steaks introduced there. However the film changes the story significantly, and introduces memorable scenes of the protagonist Detective Robert Thorn (played by Charlton Heston) clambering over people in hallways and on staircases as he investigates an assassination. This investigation reveals that a new type of protein food-stuff, the eponymous Soylent Green, cannot be derived from plankton as claimed. Instead the film ends with the horrified, wounded and desperate Thorn crying to a pressing crowd “Soylent Green is people!”

In fact, while at first sight this appears to be a solution to the problem of overpopulation, it merely perpetuates it, first sustaining the masses and then harvesting them - although like any other cycle it will lose resources as waste at every step and hence is ultimately doomed.

However despite these bleak horizons, another prominent strand of science fiction narratives took a more positive view of the ways forward. In these, overpopulation on Earth is a key driver that forces humanity to seek out its glorious futures in space. This is seen in the background of many of Robert A Heinlein’s novels. Protagonists Tom and Pat Bartlett in Time for the Stars (1956), for instance, were unplanned and grew up knowing that, as unplanned twins, they were both a social and tax burden to their family in the overcrowded world. Similarly Rod Walker, protagonist of Tunnel in the Sky (1955) is caught up in a lord-of-the-flies type situation while training for emigration from an overpopulated Earth.

Isaac Asimov and Arthur C Clarke both assumed overpopulated Earths in the background of their fiction, including the afore-mentioned Caves of Steel and other Robot stories from Asimov, and examples such as Imperial Earth (1975) by Clarke. It motivated the advertising campaigns driving emigration to Venus in The Space Merchants (1953) by Kornbluth and Pohl. It also formed the apocalyptic backdrop to Edmund Cooper’s story of space emigration The Tenth Planet (1973), amongst too many others to mention. Nor have such discussions been limited to fiction. Asimov classified overpopulation as a catastrophe of the fifth class in his 1980 book of essays A Choice of Catastrophes along with other disasters resulting from resource depletion or human technologies. Overpopulation is also one of the key drivers discussed in the early chapters of Gerard K O'Neill's influential book The High Frontier (non-fiction, 1977), which argued the case for space colonisation.

As others pointed out, extra-planetary emigration is hardly likely to be a long term solution to the problem. Robert Silverberg described an over-population (and religion) driven emigration to the stars in his 1967 novel To Open the Sky, amongst other stories. However in his 1958 short story No Way Out [3], he asked the question of its sustainability. In this story, the Secretary General of the United Nations meets with representatives of human settlements on Mars, Venus and Jupiter’s moon Callisto. In four generations, two billion people have been offloaded to these colonies, and terraforming of Ganymede and Titan are underway, but Earth continues to have more than nine billion, rising exponentially and the colonies refuse to take more. The three representatives are taken on a tour of overcrowded Earth but it’s ultimately counterproductive:

“We're deeply moved and highly sympathetic to your plight,” he. said. “We're filled with pity: the pity we'd have for an idiot who, when given a loaded gun, proceeded to blow his brains out.”

“What’s that? McClellan asked, astonished.

“Earth is vastly overcrowded; agreed. We knew that before we undertook your tour. Has it occurred to you that we haven’t grown overcrowded—and won't?“

“We have small worlds,” said Ludwig, the Callistan. “If we allowed ourselves to breed at Earth’s rate…”

“Exactly,” said Rockwood. The Venusian scowled. “We of the Outworlds have seen the inescapable need for certain self-restrictions, basing our ideas on your mistakes. And we're damned if we'll let you upset our way of life because you're too foolish to admit the existence of limitations.”

Unsurprisingly, the Colonies hold firm in their ban on emigrations, leaving the Secretary General with a dilemma.

Other stories have a similar theme - a recognition that the capacity of colony worlds to absorb excess population will inevitably fall short of the unshackled reproductive capacity of Earth, and that resistance is likely from populations generations removed from Earth loyalties. Indeed, Kim Stanley Robinson echoed the same arguments in the well-known Mars Trilogy (novels, 1992-1996) when Mars begins to resist further immigration.

However even the futures envisioned in stories such as No Way Out now appear over-optimistic. Moving as many as a billion people in a century would require transportation of almost twenty-eight thousand a day for the whole of that period, implying huge, reliable, reusable and immensely powerful spacecraft and terraforming technologies that far exceed any we can currently envisage. Interstellar options, or even interdimensional or time-travel alternatives, as envisaged in other stories, would suffer similar problems of volume. And, as Silverberg pointed out, this was still a mere drop in the ocean compared to the population growth rate.

 A Catastrophe Averted?

If overpopulation was such a pressing issue in the minds of writers in the second half of the twentieth century, many of whom envisaged dates early in the twenty-first, why aren’t we now living in the nightmare dystopia envisioned?

Well, in some sense we are. The numbers envisioned by authors such as Harrison, Nolan and Vonnegut were in the range of seven to eight billion humans on Earth. The actual figure is now 8.2 billion according to most estimates. The cramped living conditions and quality of life in many poor cities around the world is very different to that envisaged as “the American Dream”, even if it doesn’t reach the extremes of Make Room! Make Room!

UN, World Population Prospects (2024) – processed by Our World in Data

However, while the total population has risen to levels which horrified science fiction writers in prospect, the distribution of that population is perhaps different. Many of the fictions written in the 1960s and 70s imagined population growth in the United States of America which scaled in proportion to that of the species as a whole. In fact, while the world population has more than trebled since 1950 (a factor of 3.25 by 2023 according to UN statistics), the population of the USA has only doubled (a factor of 2.2) in the same time period. The population of the UK has only slightly increased (a factor of 1.4) and the trend towards flattening population growth is similar in most developed countries. The majority of growth being in less developed countries, where the average consumption of resources per individual is lower, has offset the anticipated effect of growth in urbanised, high intensity and consumption-driven environments.

The reasons for this demographic shift are well understood: the increased cost of raising children in an industrial nation, the provision of social security nets so parents are no longer dependant on their surviving children, the introduction of reliable contraception techniques, and - above all - the improved education of women - are all correlated with falling birth rates. The more modest population growth seen in industrialised countries has been compensated for by improvements in diet, in agricultural productivity, and - to some extent - a reduction in per-capita consumption relative to projections. While population continues to rise in many parts of the world, ongoing campaigns to educate, industrialise and improve healthcare in the developing world are likely to spread the same economic and social pressures that have reduced birth rates elsewhere.

This does not mean that overpopulation is a concern entirely of the past.

While the majority of the stories I have discussed here were written between 1950 and 1980, the same concerns continued to be articulated in different ways. Overpopulation narratives towards the end of the twentieth century and continuing into the twenty-first have typically reframed the problem in terms of the related issue of global climate change. I’ve discussed both stories of flooded worlds and stories of parched worlds in past entries of this blog. In both cases, population density is just one more factor in a world which has depleted its resources and simply cannot sustain the same mass of humanity. Mass population movement, such as that seen in John Lanchester’s The Wall (novel, 2019), overpopulation concerns and stories of tight population control are common in the context of ecological SF and climate fiction, or cli-fi. As in many works of the mid twentieth century, a readjustment in world population numbers is seen as an inevitable part of the consequences of climate disaster, but usually (although not always) cast as natural or inevitable rather than politically enforced. While the first hints of these environmental concerns were visible in the overpopulation fiction of the twentieth century, as for example in Hersey’s jealously walled-in Green, the focus has changed.

The idea of what a sustainable population looks like has also changed. Just to take a very recent example, The Scientists Book of the Dead by Gregor Harman appeared in the May/June 2025 edition of Analog Science Fiction and Fact. This novelette imagines a future in which, as a result of conflict, “the number of humans on the face of Gaia had dropped from an oppressive nine billion to a sustainable two hundred million”, and North and South America are returned to wilderness reserved. Even then, the story focuses on a plan to further reduce the population to a carefully selected twenty million - enough to curate Planet Earth without burdening it. As always in such stories, the question of who will survive, who will pick those survivors and by what criteria form the crux of the drama. 

In a real sense then, the last fifty years has seen a shift from a focus on what environment can do to humans - the line-sickness of Hersey and violence of Brunner - to what humans can do to environment. The idea of a planet B, of mass space colonisation as a solution to population growth, has been demonstrated to be hollow and unsustainable. Instead, education and scientific techniques have averted much of the disaster once imagined, but raised the prospect of still greater, and worldwide, disasters still to come.

Overpopulation fiction is an example of an extrapolation from trends in science fiction which has not played out as envisioned. While I often focus on science fiction predictions or concepts that have directly influenced, or been influenced by science, this topic falls into a greyer area. Certainly the narratives discussed here were influenced by scientific analysis of demographic data at the time, but it is hard to say to what extent science fiction - particularly blockbuster films such as Logan’s Run and Soylent Green - influenced subsequent developments. In this case it is likely that other, unanticipated, trends counterbalanced those foreseen. 

As always, science fiction reflects the concerns of its time. The pace of urbanisation and industrialisation in the mid-twentieth century triggered societal concerns which led to visions of high density housing as a form of urban purgatory. At a time when space travel seemed to open endless new horizons, overpopulation provided one more justification for the vast expenses and complexity of that endeavour. And as the devastating possibilities of climate change loom large over us all, climate fiction has absorbed overpopulation as just part of its more complex cause.

In truth, we do not know how many human beings the planet is capable of supporting, and in what conditions. It is almost certainly more robust than some writers anticipated, and more vulnerable in ways other than those anticipated. The worst dystopias have been averted. Others may take their place. Either way, the topic stands as an interesting insight into preoccupations in the cities of the 1970s and as a reminder - sometimes, despite the warnings of science fiction’s thought-experiments, things work out better than expected.