Overpopulation Crisis

"Titan was like most planets: too many mouths, not enough to go around."

— Thanos, Avengers: Infinity War

The population of an area, whether it be a small region, a country, a planet, or a Galactic Superpower has grown so large it is causing problems. The result might be societal instability, war, ecological catastrophe, cannibalism... the specifics do not really matter — what matters is that there are too many people and it is causing problems. This is often a feature of a dystopia and Cyberpunk, and can be used as a form of Green Aesop about uninhibited growth in a finite area.

May be prevented or resolved through the use of Population Control, settling new, uninhabited places, or even good old-fashioned Depopulation Bombs if the powers that be feel it is the only way. If unhandled, the crisis can cause The End of the World as We Know It if it grows severe enough as riots run rampant for what resources remain.

This is one of the threats of the Explosive Breeder — even if it's not malicious, the sheer amount of offspring will eventually cause trouble if left unchecked. An Eco-Terrorist may resort to a Final Solution largely out of fear of a Malthusian crisis.

The idea of overpopulation is often used by proponents to justify genocidal policies, arguing that it is easier to reduce or control the population ("coincidentally", it's usually a specific population they personally dislike or don't care for) than to figure out ways to increase or share the resources available to everyone. Sufficed to say, depending on which population they decide must be culled, it can get pretty racist and classist.

The Earth-centric version of this trope is largely broken in contemporary and 20 Minutes into the Future stories due to technological and societal advancements in our real world: for example, if anything our industrialized farming and agricultural technologies lead us to over-produce food, and problems with starvation are more about political and economic questions of distribution (aka "who is permitted access to the food?") rather than "we do not have enough to feed everyone". Many nations have also started to project a population decline (and all the problems that brings) due to undergoing a demographic transition. However, this hasn't stopped people from using the idea of overpopulation as a bad faith argument for their own agendas (such as anti-immigration). See the Analysis page for more details about how the problems of "overpopulation" have many different causes.

---

Examples:

Anime & Manga

• In the Gundam franchise, this is the impetus behind building the Space Colonies in many shows: the Earth had become overpopulated, so enormous space stations capable of supporting billions of people are built in orbit. A few series have gone further and included a Mars terraformation project in addition.
• Tengen Toppa Gurren Lagann: Adai village has no ability to expand its pool of resources, and so limits its population to exactly 100. The village's leader presents this idea as religious dogma (from an ancient text no one can actually read), and enforces it by banishing someone whenever a birth brings things over the limit. Note that it's implied the village has done this for hundreds or thousands of years, but an indefinitely stable population would require a thousand or more people.

Comic Books

• Judge Dredd: Part of the reason the setting is so crime-ridden is that most of the planet was rendered uninhabitable by nuclear war, forcing people to live in the megacities. The only alternative consists of trying to live in the Cursed Earth, the radioactive Death World outside, which is basically suicide (though some hardier people and mutants manage to survive out there). Exacerbating the problem is the equally high population of Job Stealing Robots, which keeps unemployment rates soaring.
• In a '90s Silver Surfer arc, Death resurrected Thanos and tasked him with destroying half of the universe's sentient life in order to prevent a massive population crisis. Thanos demonstrated the problem to the Surfer by showing him the effects that overpopulation and a lack of natural resources had on an inhabited planet, and claimed that the rest of the universe would soon meet with a similar fate. This plot eventually led to The Infinity Gauntlet crossover, where Thanos used the Infinity Gems to accomplish Death's goal.

Fan Works

• The Great Alicorn Hunt: The idea of an overpopulation crisis is mocked when Luna and Twilight discuss the pony version of Malthus, whose predictions regarding overpopulation would have had them all starve to death eight hundred years before. Luna says that "he was a buffoon who insisted that we would all starve to death because Celestia and I 'let' Equestria's population grow too fast, and that our numbers would exceed our farmers' ability to feed us all." She then proceeds to point out that Malthus "did not account for our farmers learning new and better ways to grow; he did not account for our ability to get more out of less land, or that we would have more land, period. He certainly did not account for the fact that, as our prosperity grew, our birth rate declined... And even when the blessings of foals were abundant, we had more than a surfeit of food, and room, and love for all of them." However, she also confirms that they have several contingency plans just in case, with their Panacea plan (to create a cure for the process of decay with old age, letting ponies have far longer to create, innovate and generally improve, letting them spread out among the stars) being one of them.
• Rocketship Voyager is a Star Trek: Voyager fanfic written In the Style of a 1954 sci-fi magazine pulp, set in the far future of 2020. Earth is on the verge of famine with a population of over seven billion crammed into megacities. It's implied the Green Revolution never got started due to war and political conflict. The birth control pill has been invented but it had little effect on the morals of society, so there's increasing pressure for the aggressive colonization of Mars and Venus rather than adopt controversial measures of Population Control.

Films — Live-Action

• In Avengers: Infinity War, it's revealed that overpopulation and the subsequent abuse of natural resources led to the destruction of Titan and the death of all its people... except for Thanos. His desire to save the rest of the universe from suffering the same fate as Titan has motivated his actions in the Marvel Cinematic Universe ever since, and in Infinity War, his plan is to finally gather all the Infinity Stones and use their combined power to simultaneously wipe out half the universe's population. He ultimately succeeds.
  • We learn that Thanos had taken Gamora from her homeworld as a child after executing half the planet's population, but small visual details in Guardians of the Galaxy (2014) show that Gamora is now the last survivor, meaning Thanos' "grand plan" was a failure even then.
  • Avengers: Endgame shows that it backfired hard. Five years after the Snap, instead of teeming with life, from the brief shots we see of New York and San Francisco, indicate that the Earth left behind has stagnated at best, and is rotting at worst (and the space-based Avengers (Captain Marvel, Rocket Racoon, Nebula), state that the rest of the universe is no better, if not worse, off) — and that's on top of the wave of terror Thanos unleashed on his way to claim the Stones. Whales are returning to the Hudson River, and depopulated areas have been claimed by nature, but these small improvements pale in comparison to crumbling societies and despairing and barely-functional populations across the universe.
• In Conquest of Space, this is given as a reason for the mission to Mars: to get its resources to prevent an overpopulation crisis on Earth. It depends on Artistic License - Astronomy since in reality, Mars is a cold and barren rock, whereas the Mars in the film has soil that a seed from Earth can sprout in.
• Elysium: Among the problems that plague the dystopian Earth of the future is overpopulation, along with high crime, poverty, and medicine being restricted to the rich on Elysium. At the end of the film, all of Earth's people are approved as Elysium citizens and so can receive medicine, but the director admitted afterward that this was an Esoteric Happy Ending that would only worsen the overpopulation problem (though it does seem like contraception may also be provided).
• In Godzilla: King of the Monsters (2019), Emma Russell, the human who frees King Ghidorah, believes that the Earth is overpopulated with humans leading to depletion of resources and pollution, and feels that releasing the monsters will help restore the earth to its natural green state. Of course, none of the protagonists support her eco-radical theory about releasing the monsters to restore balance to the ecosystem and environment, as King Ghidorah is even more destructive than the humans.
• The Big Bad Ensemble of Grimsby justify their plans to create a virus that is fatal to humans in order to curb overpopulation. They also believe the virus can kill off the "stupid" people who are a waste of space as all they ever do is eat and reproduce.
• Rampage (2009) has Bill Williamson, an angry and highly intelligent man working a low-paying job as an auto mechanic, go on a killing spree upon his hometown of Tenderville, Oregon and he uses this trope as his Casus belli to justify his killings.
• An overpopulation-induced resource crunch is stated in the introduction of Serenity (2005) to have prompted the settlement of the star cluster the Firefly franchise takes place in, and led to Earth becoming Earth That Was.
• A central theme in Soylent Green. Earth is so overpopulated that the only way to feed the people (other than the wealthy who can afford normal food) is through a product called Soylent Red and Yellow, which is made from processed plankton, and even that is in short supply. A new product called Soylent Green comes at the market and in the film's climax it turns out that the oceans are dead, have been for some time, and Soylent Green is made of people.
• Spider-Man: No Way Home: This is what the botched memory erasure spell threatens to inflict on the MCU. Since Peter's last-second alterations caused the spell to end up being "everyone who already knows Peter Parker is Spider-Man should still remember", this ends up attracting literally everyone who knows from the infinite number of timelines in the multiverse towards the Marvel Cinematic Universe.
• Z.P.G. (short for "Zero Population Growth") features a world so overcrowded that having babies is banned for thirty years on pain of death. The plot involves a couple having a baby in secret and having to flee.

Literature

• In Aeon 14, the Sol system's government resorted to extrasolar colonization beginning in the 2100s to try and deal with population-induced resource strains, hence the colony ship Intrepid around which the series revolves. Even so, it's mentioned once in the early books that the Sol system's population in 4123 is now so high that they're in danger of mining out the entire Sol system within the main characters' (admittedly hundreds of years long) lifetimes. The advent of Faster-Than-Light Travel in the 5,000 year Time Dilation-induced Time Skip between books 3 and 4 takes the strain off, but also causes a partial collapse of civilization and loss of much knowledge because interstellar warfare is now practical and humanity no longer has to be as efficient with its resources.
• In "Billennium" by JG Ballard, the world population is over 20 billion, most of the planet is used for agriculture, roads are permanently filled with crowds of pedestrians so that people have to weave through a Mobstacle Course every time they want to cross the street, and each person is limited to four square metres of living space, with plans to reduce the allocation even further.
• Referenced in A Christmas Carol, when Scrooge says that the poor should die in order to "decrease the surplus population." At the time this was written, overpopulation fears were often cited to justify the mistreatment of the poor.
• Dark Life: Though the increase demand for land is actually cause by sea levels rising rather than a population boom, but the effect is basically the same. Most people live in one or two room apartments crammed into buildings, Space is considered a status symbol (there are even waiting lists to move to apartments that are both more spacious and higher up) and story focus on the small group of people who had colonize the sea floor in an attempt to reclaim the land lost to the sea.
• Ender's Game: Due to overpopulation, most of Earth's nations have enforced laws stating families are to have no more than two children. However, a few nations such as Poland openly flout the law, with many large families but the consequence being that only the first two children are eligible for public education and benefits. The protagonist, Ender, is a rare example of a state-approved Third, as the International Fleet authorized his parents to have another child because they recognized military potential in their first two. Since Peter and Valentine were examined but rejected for various reasons (Peter for being too aggressive, Valentine as too pacifistic), the military hopes Ender might be a balance of their traits.
• Overpopulation problems are a recurring theme in many of Robert A. Heinlein's novels, to which the solution is often Faster-Than-Light Travel:
  • When the Howards' families return to Earth at the end of Methuselah's Children they find that the planet has become so crowded that there's literally no room left for them, fortunately one of the Howards has invented FTL and offers it freely. Still, in the distant sequel Time Enough for Love Lazarus Long mentions in one of his stories that at one point Earth's government declared everyone over 70 to be legally dead in an attempt at population control.
  • Tunnel in the Sky: China apparently conquered Australia and paved over the entire continent to make room for its growing population before the Portal Network was developed, now they chuck hordes of settlers to new worlds through the gates.
  • Starship Troopers: Rico is assigned a class essay on how war is always the result of overpopulation, from the Crusades to the current Bug War. And that humanity doesn't dare institute Population Control, lest some other species like the Bugs expand first and wipe them out for more real estate.
  • Farmer in the Sky: The Earth has so many people that everyone on the planet is put on strict food rationing. It's the major reason why the protagonists decide to emigrate to Ganymede (one of Jupiter's moons). Late in the novel one of the characters says that Earth's overpopulation will inevitably lead to a nuclear war within 40-70 years.
  • Time for the Stars. The family of the twin protagonists live just above the poverty line because their birth raised them above the tax threshold. It's mentioned that the Earth barely has enough food to feed its population of five billion despite colonising the solar system, melting the Greenland icecap, putting a lake in the Sahara and farming the steppes.
• Industrial Society and Its Future: This is one of many modern problems that Kaczynski blames on the system.
• In Daniel Quinn's Ishmael (1992), the title character (an intelligent ape) says that world population will increase as long as food production increases. A crisis like this will inevitably happen unless food production is cut down to a more natural scale, even though it means people in poorer areas will starve.
• In Known Space, Earth is so crowded that picking pockets isn't illegal — how could it be enforced?
• Make Room! Make Room! is set on an overcrowded future Earth. American ports are swamped by shiploads of starving Asian refugees; a wealthy man's mistress is allowed to pour the juices from his steak on her oatmeal as a special treat. Set in 1999 when the world population is an unmanageable 7 billion.
• In "The Marching Morons" by Cyril M. Kornbluth, Barlow, a real-estate salesman and conman from 1988 (the story itself was written in 1951), is awoken from accidental suspended animation centuries into the future and discovers an overpopulated world of 5 billion "morons", where the average IQ is 45. A small population (3 million) of intellectuals are forced to work around the clock to keep society from collapsing, while also trying desperately to keep the "morons" from having enormous families, which is essentially impossible, as every basic human drive is based around procreation. Barlow, using his experiences in selling worthless properties to suckers, ends up proposing a Final Solution by tricking the majority of humanity into killing themselves through a phony planetary colonization scheme, but doesn't realize until it's too late that instead of rewarding him, the elite intends to send him to his death right alongside his victims, since they blame him for the dismal future as a representative of the past.
• In Fred Hoyle's October The First Is Too Late, a time-traveller from the future explains that civilisations have risen and collapsed half a dozen times since the present day; each time, the civilisation was brought down by overpopulation leading to war.
• The Ant's plot to kill the dinosaurs in Of Ants and Dinosaurs is kicked off when the dinosaurs refuse to get their population under control.
• In the backstory of the RCN series, Earth was so overpopulated that it started shipping people to offworld colonies without their consent, which eventually led to a galaxy-wide war that ended in a new dark age and Earth being so thoroughly bombarded with asteroids that the continents were rendered unrecognizable. Adele once wryly observes that, technically, Earth got what it wanted.
• In Stand on Zanzibar by John Brunner, the world is so overcrowded that people with minor birth defects can't get permits to breed.
  • In The Sheep Look Up by the same author, the problem manifests as extreme pollution.
• In The Starchild Trilogy, the population of Earth has reached the thirteen billion mark, and the only thing which has prevented chaos and a massive die-off is the dictatorial control of the powerful computer known as "The Plan of Man".
• In The Three Stigmata of Palmer Eldritch, all the planets of the solar system have been colonized, but Earth is still so overpopulated that the government has had to institute a draft to get people moving to the colonies fast enough. Life on the colonies isn't terrible, but it's harsh enough that volunteers don't begin to keep up with Earth's needs. Deferments are available for those with sufficiently important jobs, but this just adds an extra fear to the fear of losing your job.
• In "Tomorrow and Tomorrow and Tomorrow" by Kurt Vonnegut, overpopulation is connected to the invention of a medicine called anti-gerasone, which stops the aging process and people no longer die of old age and related diseases as long as they keep taking it. It is cheap and easily obtained, made from mud and common flowers. The world now suffers from severe overpopulation, lack of living space and shortages of food and resources.
• Three of George R. R. Martin's Tuf Voyaging stories (''Loaves and Fishes", "Second Helpings" and "Manna from Heaven") chronicle Haviland Tuf's encounters with the people of the planet S'uthlam. Their religion has the doctrine that all life is sacred and that humans should, therefore, breed as much as possible.^note And part of that is the belief that every child they have could potentially be the next great genius, and it's their duty to help bring that about. As a result, their planet is dangerously overpopulated. The government repeatedly tries to seize Tuf's Lost Technology bio-warship to use in conquering other planets and relieving population pressure, he tries to appease them by providing new food sources and the third and last time he adds a Sterility Plague to the new crops.
• In The Vazula Chronicles, the triple kingdoms are becoming increasingly overcrowded, and Tilssted is starting to encroach into the kelp farms to the north, even though much of the merpeople's technology depends on kelp leaves. Merletta wonders if dry land holds knowledge or resources that could help with the crisis. In A Kingdom Restored, she learns how the triple kingdoms have traditionally dealt with the problem — by inciting a war between the cities to cull the population.
• In the Warrior Cats prequel series Dawn of the Clans, the series starts with the Tribe of Rushing Water suffering from overpopulation: the Tribe has grown too big to survive on the amount of prey that their environment can provide, and cats are starving to death. Their leader has a vision of new lands teeming with prey, and half the Tribe leaves, eventually becoming the forest Clans, while the other half remains in their mountain home and is able to support themselves better with fewer mouths to feed.
• The setting for The White Men, is a dystopian future version of Denmark, which underwent such a crisis and transformed into a fascist state where the State Sec, the titular "White Men", kills off anyone who they deem unfit to live, which includes the handicapped and chronically-ill, people who commit any sort of crime, even minor ones, anyone who reaches the age of 65, and even students who fail to pass their exams with a high enough grade. Throughout the story, it becomes evident that even if these draconian and inhumane policies were at some point necessary to solve the crisis, that is definitely not the case anymore, as the country currently teeters on the edge on of a serious underpopulation crisis, and it is obvious that the fascist government only still upholds them as a means of controlling the leftover population through the fear they instil in them.
• Isaac Asimov wrote "The Winnowing", where six billion people on the planet has led to widespread famine. While that prediction has shown to be wrong in Real Life, at the time of its writing, it was definitely an example of this trope. Subverted in the same story, since the World Food Organization seems to have the resources on hand to provide adequate food to the world but would rather just kill off the poorest areas (and have coerced a scientist into helping them).
• This was the main theme in many of William R. Catton's writings, including his books Overshoot (1980) and Bottleneck (2009).
• In Worm, the predecessors of the Entities experienced cycles of overpopulation followed by wars over the remaining resources which would push them to near-extinction. Realizing that the cycle was unsustainable as the nutrient sources were depleting faster each time, they devised the plan to leave their homeworld and infest other planets. Their descendants are aware that even this is a temporary solution, as eventually there will be no new planets to feed on and are trying to find a solution.

Live-Action TV

• Aftermath: The episode "Population Overload" explores exactly this, when the population of Earth spontaneously doubles overnight. At first humanity tries to cope by rationing resources and rapidly expanding construction, but eventually society breaks down, resulting in huge population movements and an eventual Depopulation Bomb.
• The Outer Limits (1995):
  • In "Manifest Destiny", Earth is severely overpopulated and other planets are being terraformed and colonized as a result.
  • In "Stasis", Earth's severe overpopulation results in its resources being significantly depleted.
• Overpopulation is one of the factors that jumpstarts the plot in Terra Nova (the other one being extreme pollution) - the plot being "send some humans through a wormhole to an alternate Earth resembling the Cretaceous Period."
• The premise of Torchwood: Miracle Day is that people have stopped dying. Governments do the math and realise that the world population level is going to rise to unsustainable levels within a few years.
• In the Anvilicious Star Trek: The Original Series episode "The Mark of Gideon", the crew visit a planet which is so overpopulated that even the president's office has a crowd of people milling around in the background. The people of the planet believe "all life is sacred" and reject birth control. They also have medicine so advanced that people never get sick and live to a very old age.

Music

• Pink Floyd's early single "Point Me at the Sky" suggests this scenario for 2005.
  ''If you survive
  Till Two Thousand and Five,
  I hope you're exceedingly thin;
  For if you are stout,
  You will have to breathe out
  While the people around you breathe in.

Mythology and Religion

• The OT III doctrine of Scientology — one of the most well-known elements of it due to being famously illustrated by South Park — says that humans are the end result of galactic conqueror Xenu dealing with an overpopulation crisis 75 million years ago across 76 planets, each with an average population of 178 billion. Countless aliens were gathered, frozen, and compacted into singular bodies as a means of addressing it.

Newspaper Comics

• Calvin and Hobbes: One infamous Sunday strip had Calvin deliver a report on overpopulation where a pair of deer shoot an office worker to help curb the population and prevent famine, in a ghoulish inversion of a common (and accurate) justification for deer hunting. Unsurprisingly, this results in yet another note from school being sent to Calvins parents.

Tabletop Games

• In Homeworlds, a star system is overpopulated if it contains more than three pieces of the same color. Players can declare a "catastrophe" at an overpopulated system, destroying all the pieces in the overpopulated color. If a star in the system matches the overpopulated color, the star itself is destroyed. If that star is the system's only star, the whole system is destroyed.
• Warhammer 40,000
  • Of the Imperium of Man's many, many problems, this is surprisingly not one of them. Yes, many worlds house billions of people in Hive cities, but this is actually encouraged. Most of the logistics and spacing problems are handwaved (e.g. many worlds resort to recycling the dead into edible material), but it recognizes keeping people suppressed, indoctrinated, and packed like sardines is a very efficient way to manage very large populations. It's something of a joke that the Imperium is short on everything but people, and human labor, press-ganged or volunteered, is a major driver of the Imperium's military and industrial forces.
  • Later Edition show that many Hives are supported by other worlds in their system. This is actually played straight on Earth, where the population is so massive that there simply isn't enough food or jobs to go around.
  • Also averted with the Orks. Humanity is the most populous species behind only the Orks, and they manage to support their population by bringing their ecology with them to keep themselves fed, and the occasional mass migration. Also, they have a strong population control in the form of constant violence aimed in all directions.

Video Games

• In Black & White 2, it's not the population itself so much as population density that causes problems. Your citizens will become unhappy if there is insufficient housing or food resources, or if their housing is too tightly packed (e.g. "skyscrapers", really tenements, are efficient with space but bad for happiness, while mansions with lots of space between them make for happy citizens but require lots of building room; villa clusters are generally the best choice).
• The Ark in Brink! is a City on the Water which was originally designed to host a population of 5000, but an influx of refugees due to global warming caused its population to swell to 45000. As a result, many of these refugees were forced to live in poorly designed and shoddily constructed shantytowns, and many feel resentment toward The Founders, Ark's original inhabitants who live in safety and luxury.
• In Civilization V every city has an assigned number representing its population. Densely populated cities will produce more research and are able to work more tiles and specialist spots. They also produce more unhappiness which, if left to fester will severely decrease your nations growth and golden age frequency. If your citizens are unhappy enough, civil wars might break out.
• Crusader Kings II:
  • Played with for nomads such as the Khazars and Mongols. The Nomad government form has a special resource called "population" and get bigger armies and increased income the longer it is allowed to grow. Once it reaches 90% of maximum, they gain access to the unique "Nomad Invasion" casus belli which allows them to conquer entire de jure kingdoms from other realms. This essentially means overpopulation is good for the nomads and bad for everyone else (since their cavalry- and horse archer-heavy armies can be difficult to counter).
  • The "Prosperity" measurement added in The Reaper's Due measures wealth and population of a province. Higher Prosperity increases your tax income and can unlock additional holding slots in a province, but also increases the province's vulnerability to epidemics. It also has an opposite form, "Depopulation".
• Mass Effect:
  • Even after the development of Faster-Than-Light Travel, it's noted In-Universe that in the late 22nd Century, Earth is still vastly overpopulated, with over 11 billion humans and an unknown number of aliens living on the planet, and dealing with problems caused by environmental damage which peaked a century ago. Earth's overpopulation and pollution is mocked by many aliens in the series, as an indication of humanity's inability to get its own "house in order", so to speak. A possible origin for protagonist Commander Shepard is to have grown up in a gang of orphan criminals in a polluted megatropolis on Earth.
  • Drell society collapsed into warlordism due to the overpopulation of their homeworld, which they were unable to escape due to having no element zero. The hanar took pity on them and brought many of the survivors to their own homeworld Kahje as a Servant Race.
    Shepard: Why was your race going extinct?
    Thane: Overpopulation. That must sound trite to you. Humans developed mass effect drive before the problem became acute. Our homeworld, Rakhana, had few resources. We hadn't even developed fusion power when the soil began to fail from overuse and pollution. The hanar found us a century ago. They sent hundreds of ships. Evacuated thousands of us. Billions more had to be left behind.
    Shepard: What's the state of Rakhana now?
    Thane: Do you read your philosophers? A man named Thomas Hobbes? "When all the world is overcharged with inhabitants, then the last remedy of all is war, which provideth for every man, by victory or death." As Rakhana died around them my people slaughtered each other for mouthfuls of water. Crumbs of food.
  • After being uplifted from their homeworld to fight rachni, the krogans found little opposition that would keep their natural birthrate in check, often overpopulating planets in just a few generations. The salarians responded by devising a genophage which would make only one in a thousand krogan births viable. It would supposedly revert krogans' birthrate to what it was back on Tuchanka with all the fatality rates taken into account, which was sustainable... But the krogans saw the genophage as a particularly cowardly act of genocide, and turned to mercenarism to cope with their natural Blood Knight tendencies... which put their species at actual risk of extinction.
  • The salarians themselves narrowly averted an overpopulation crisis very early in their society's development. Salarians are haplo-diploid egg layers; females lay eggs at regular intervals, with unfertilized eggs hatching into males and fertilized eggs hatching into females. This led to problems very much like those seen on Earth and Rakhana because of how quickly they reproduced. The salarians solved the problem by only allowing ten percent of all eggs to be fertilized, keeping their reproduction growth at a stable level. The quickness with which all salarians accepted this solution is why they expected the krogan to have the same reaction to the Genophage.
• Inverted in Pharaoh, and Emperor: Rise of the Middle Kingdom where underpopulation is a much bigger problem: due to the game mechanics, huge populations are easier to maintain by keeping the population happy in attractive, high-density housing rather than vast slums (the basic hut holds 5-20 people, the best high-density housing holds 80). Yes, the people consume more, but the higher population means more people to produce goods at a much faster rate than consumed.
• Eternal Evil have the Bad Ending depicting humanity's population, as warned by the Vampire Lord, eventually going out of control to beyond 14 billion, and mankind's damage to the environment beyond repair. It leads to a massive power struggle and depopulation, with 43 million people surviving in the aftermath of the 2104 war. You're a human-turned-immortal vampire at this point and you get to witness the downfall of humanity, as predicted.
• Lysandre in Pokémon X and Y is a Mad Scientist, Eco-Terrorist, and Misanthrope Supreme who seeks to prevent fighting over resources with a Final Solution using the Ultimate Weapon to kill everyone but Team Flare.
• In Stellaris: Population can cause no shortage of problems if not handled.
  • As the population working your Empire's jobs increases, the demand for consumer goods and amenities increase. Both are produced by specific jobs which means you need to set aside a subset of your population and economy to keep the rest of the population happy as failing to do this will lower the planet's stability, which lowers production on top of the risk that the unhappy population will turn to crime to get what they want.
  • Overcrowding (as in, too many people, not enough housing) will eventually also erode the stability of the planet, but unless your entire Galactic Superpower is bursting to the brim, the people will generally just move to greener, more spacious pastures. Of course, no one says you have to give the people what they want - if you want to maintain the planet's stability through force, that's perfectly doable
  • Overcrowding is, however, dwarfed by the damage that having too few jobs for a population can present. People without a home generally tend to make do with what they can, but if they don't have a job, they will near invariably turn to a life of crime to keep themselves fed. The game warns you when there's a substantial risk of this and prompts you to give special benefits to the unemployed (Increasing the strain on your ressources) or risk the increased crime (reducing the output of the planet). You can avoid this completely by enacting a policy of civil welfare - which increases population happiness as well as preventing the unemployment crime, but welfare does not come cheap either.

Webcomics

• The fear of this — and the damage it could to the planet — is the primary motivation of Malthus, co-leader of the Light Demons, in White Dark Life. As such, he seeks to kill most of the planet's population to ease the strain on the environment.

Western Animation

• In Brickleberry, Steve creates an adorable and marketable hybrid species of rabbit and squirrels called Squabbits to attract tourists. Problem is, not only does the species breed even faster than its progenitors, it's also virtually unkillable, causing a massive population boom that devours almost all plant life in the park and soon turns the Squabbits carnivorous with a preference for human flesh. The rangers manage to defeat the horde by feeding them Pamela Anderson (who was there as part of a PETA protest), who turns out to be so riddled with toxins and disease that every single Squabbit dies a horrific and agonizing death.
• In the Ed, Edd n Eddy episode "Flea-Bitten Ed", the Eds agree to clean up Rolf's farm animals. Ed suffers a severe allergic reaction to the rabbits and loses track of two rabbits, who start multiplying through rapid reproduction and overwhelm the Cul-de-sac in the end. The Eds got out lucky by managing to escape to the roof (with a TV and couch) and the episode ends with Eddy screaming at the other kids suffocating from the rabbit flood to shut up so he can watch TV.
• In the Futurama episode "The Birdbot of Ice-Catraz", a wildlife preserve of penguins on Pluto gets covered in liquid dark matter that drastically increases their egg production (and the males started laying eggs, too), leading to them overpopulating and an Animal Wrongs Group deciding to give them a Mercy Kill to save them from a slower, more excruciating death when they exhaust their food supply.
• The South Park episode "Goobacks" depicts the world in 3045 as suffering from overpopulation to the point that people are time-travelling back to the present day to find jobs and a better life.
• Hell itself is suffering from overpopulation in Hazbin Hotel. The current solution to the problem is an annual "cleanse" where angels from Heaven massacre as many demons as they can in a set amount of time. Charlie, the Princess of Hell, wants to create a humane alternative to the problem by opening a hotel to rehabilitate sinners so their redeemed souls can go to Heaven.

Real Life

• The concern for overpopulation is Older Than Feudalism, having been raised by Plato and Aristotle in the fourth century BC. Note the world population was then around two hundred million, or about the same as present-day Nigeria. To be fair, they were writing from overcrowded Athens.
• Around the turn of the 19th century, Thomas Robert Malthus warned about overpopulation in his book An Essay on the Principle of Population. Overpopulation became a concern during the Victorian era, with proposed solutions tending to be of the Kill the Poor variety. Malthus' theories were cited to justify Britain allowing the Irish Potato Famine to go on.
• There was another overpopulation scare in the Cold War era, spurred by the 1968 book The Population Bomb. The population of Earth was rising and there would soon be too many people to sustain. Even at the time, the claims in the book were questionable, since it depended on unrealistic projections and ignored real-world demographics. Since then technology has marched on along with society and not only is the population growth slowing down, but we also produce more food than ever and the percentage of people living in extreme poverty has never been as low as of this writing.
• Although the idea of the entire Earth becoming overpopulated has been largely discredited. Localized overpopulation has still been a common concern; Many cities are struggling under the increased traffic that increased population brings because the original city was built in such a way that roads that formerly allowed for horse-drawn carts now need to support the eighteen-wheeler trucks and the vast numbers of cars needed to support the population. Add in a need to dig up roads to perform sewer/cable/pipeline maintenance and you have the city equivalent of growing pains.
• Some have argued the Black Death was, in part, the symptom of an overpopulation crisis in the early 14th century. Much of the farmland in Europe had been used up, and many peasants had already suffered crippling famine in the decades before. The death toll was high because many peasants were already weakened by malnutrition. The Black Death may have helped end feudalism since the surviving peasants had enough bargaining power to demand higher wages.
• Some have argued the Rwandan Genocide may have been, in part, a Malthusian crisis. Rwanda by the early nineties had an incredibly high population density. Much of the farmland had been used up and living standards had been in decline for several decades. Jared Diamond reported that some Rwandans defend the genocide as an act of population control.
• Natural historian Sir David Attenborough is controversially an avid proponent of population control for the sake of the environment, although his proposals are more on the benign side, being limited to furthering sex education and access to contraceptives in developing countries.
• China's successful One Child Policy was a result of this belief. However, due to the culture having it where the males of the family took care of their parents in their elder years, this policy had the side effect of Chinese families killing newborn daughters or putting them up for adoption in the West, causing a massive imbalance of males to females in the general population. In 2015 the policy was lifted to a two-child limit and was lifted to a three-child limit in 2021. Ironically, despite lifting the limit, now people don't want to have kids, because of...
• The demographic transition, the real-life inversion of this trope. After The Baby Boom of the mid-20th century, birth rates proceeded to collapse in the world's wealthier countries to around replacement level (2.1 children per woman) or below. The reason for this can be summed up thusly: between urbanization, the spread of contraception, widespread education (especially for women), old-age pensions, bans on child labor, advances in health care and life expectancy, the obsolescence of massive armies in the face of Mutually Assured Destruction, the mechanization of agriculture, and the rise of a post-industrial, knowledge-based economy that needed specialized workers as opposed to a large pool of laborers, it was no longer necessary or even desirable to have a large family as opposed to just one or two kids who parents could devote their full attention to. The world's industrialized nations were the first to experience the demographic transition in the '70s and '80s, but it has since either happened or started to happen everywhere on Earth, from Latin America to the Middle East.
• Another inversion of this trope is the Cornucopian thesis, which states large populations, rather than creating resource crises, can produce more potential innovators who can engineer solutions to potential shortfalls in commodities. Julian Simon, an economist and believer in human ingenuity, publically bet Paul Erlich that between 1980 and 1990, the price of certain metals would fall. Julian Simon was proven correct because there were innovations that made the use of these metals less important.
• In many parts of the world, especially the former Soviet bloc and East Asia, populations are beginning to stagnate or have even gone down. The book Empty Planet: The Shock of Global Population Decline by Darrell Bricker and John Ibbitson outlines a possible future where this trope gives way to the mid-21st century to an Underpopulation Crisis, one that they imagine will be marked on the one hand by higher wages and living standards for workers and reduced inequality but on the other by labor shortages, inflation, and strained pension systems.
• Stephen Emmott warned that reducing demographic pressure on the environment could be done by urgently consuming fewer raw materials.
• Economists like Amartya Sen argue that while famines are often blamed on drought or overpopulation, oftentimes political systems can determine whether a food shortage becomes a famine. In colonial systems or autocracies without any accountability, a famine can occur if the ruling elite has no incentive to feed the population, or more sinisterly if the government is downright hateful to its subjects and wishes to starve them. The Raj periodically had famines because the British government was reluctant (at best) to help its non-white subjects, but independent democratic India hasn't had any massive famine in times of drought because local governments are more willing to intervene on behalf of the population.

---