Absurdly Huge Population

The individual human being is unpredictable, but the reactions of human mobs, Seldon found, could be treated statistically. The larger the mob, the greater the accuracy that could be achieved. And the size of the human masses that Seldon worked with was no less than the population of the Galaxy which in his time was numbered in the quintillions.

— Narration, "Prelude" Second Foundation

It's the future— either close or distant. You have the ray guns, the jet packs, and the spaceships. But you need a way of making things seem more 'real', like society itself has deeply changed. How?

Up the number of people in the world by a couple billion, that's how! Despite Earth's population growth currently slowing down and estimated to peter out between the 9th to the 13th billion (barring unexpected circumstances) as developing countries go through the four stages of demographic transition, the concept of "Of course there will be more people in the future, duh!" is one that seems self-evident to many readers, and thus it's an easy way to get across how far into the future you are, with populations only growing bigger as the decades (and centuries and millennia) go on. These populations will often be so mind-bogglingly huge that they are unfathomable to our current worldview.

How such a large population came to be or is sustained, is rarely addressed, though there's sometimes an in-show explanation (often involving colonizing other planets and people expanding to fill the new living space). It's popular in space operas with their sprawling galactic superpowers.

This trope can easily collide with Science Marches On, since figures which match this trope in older fiction might have already been achieved in real life. Make Room! Make Room! has seven billion people on Earth^note Which we reached late October 2011, while Isaac Asimov's short story "The Winnowing" has humanity starving at six^note Of the 7.5 billion people of today, a little less than 800 million are starving, a number that's falling despite the increase in population; this leaves us with 6.7 billion people who have food on their plate. As of 2020 the Earth's food production is enough to feed 10 billion people — the bigger issue according to most experts is the distribution of that food.

Often overlaps with Overpopulation Crisis when the enormous population size causes problems, but settings can have huge populations without suffering negative consequences as well. Contrast Depopulation Bomb.

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Examples:

Asian Animation

• Dragon Ball: Inverted. According to Dragon Ball Minus, the Saiyan population was only a few thousand on their home planet before Frieza destroyed them. It implied because there was a warrior race constantly at war with other races and each other, it was difficult for them to increase their numbers.
• Planet Xing, the primary setting of Happy Heroes, has 60 billion inhabitants according to what Little M. tells Big M. in the first episode.

Fan Works

• Parodied in Plan 7 of 9 from Outer Space.
  "The outlook was grim, with doomsayers predicting the extinction of blondes, and a world populated by six and a half billion people where we'd all be forced to eat rice."

Film — Live-Action

• In The Fifth Element, the President of Earth mentions "some 100 billion of my fellow citizens", although these might not all be on Earth.
• Star Wars: Plays with the usual connotations of the trope in that the Star Wars setting as a whole takes place "A long time ago in a galaxy far, far away." Yet this is easy to mistake for taking place in the future with sci-fi tech and City Planets. One such is Coruscant, the capital of the Galactic Republic and later the Galactic Empire, has a population topping a trillion all by itself according to a reference book published prior to The Force Awakens's release. The entire galaxy has a million inhabited planets, according to some sources, so the galactic population could be a quadrillion. According to the original movie novelization, a million worlds is a tiny fraction of the galaxy, but it may be including the uninhabited planets as well.
• Soylent Green (and the Harry Harrison novel that inspired it, Make Room! Make Room!) have a 21st-century New York City populated by 35-40 million people (actual 2017 population estimate: 8.6 million). If that growth is representative of the rest of the planet, that means around 35 billion people live on Earth.

Literature

• The Millennial Project: Colonizing The Galaxy in Eight Easy Steps considers the intellectual consequences of living in a society where there are "5 billion billion people". While there would be many problems, such a society could invest vast intellectual resources solving those problems.
• Isaac Asimov
  • Foundation Series:
    • A basic premise in this series is that only the actions of large populations can be predicted because individual reactions are far too random to accurately model with mathematics. The setting describes twenty-five million inhabited planets in the galaxy, with a total population extending from quadrillions to the quintillions. While the series as a whole qualifies, the lower bound would mean the average inhabited planet doesn't: "100 quadrillions" gives each planet a population of 4 billion.^note This is roughly double the Earth's population circa 1950s. It didn't reach the four billion population mark until two decades later. This shows that even when trying to demonstrate an obscenely huge population, at the galactic scale you end up at a fairly reasonable number.
    • "The Psychohistorians": Based on the Encyclopedia Galactica entry on Trantor, the planet is the capital of the Galactic Empire and the population is in excess of 40 billion. It is also fed by the daily combined output of 20 farm planets.
    • "The General": The planet Trantor, capital of the Galactic Empire, is populated entirely of government administrators, and their population is said to be 40 billions, requiring the combined output of twenty farm planets. This is Trantor after decaying to only the core galactic worlds, though citizens believe themselves to represent the Empire's peak because they have grown so large.
    • Foundation's Edge: The exposition given at the start of chapter 5, "Speaker", says that the planet Trantor's population was capped, by law, at forty-five billions of people. However, this means that if Trantor had a surface area equivalent to Earth, then the vast City Planet had a population density comparable to half that of Alaska's largest city.
  • "The Last Question": Just before the end of the universe, it is populated by "a trillion, trillion, trillion" people, spread all over the universe.
  • "2430 A.D.": The last zoo is being shut down to provide Earth with a perfect, stable society... no animals, no plants except for edible plankton, and as many humans as the planet can support - fifteen trillion.
• Aeon 14: The colony ship GSS Intrepid around which the story revolves has a population/crew of millions all on its own, and individual space stations with populations in the hundreds of billions are described: a 9th millennium 1600-kilometer space station with 150 billion residents is seen as only mildly impressive by protagonist Tanis Richards, who is from 42nd century Earth when the Sol system had probably tens of trillions of people and had stripped Uranus and Neptune of their atmospheres and mined or combined almost every rock in the system for living space and resources.
• Robert Silverberg's novel The World Inside is set on Earth in the year 2381, when the population of the planet has reached 75 billion people. Population growth has skyrocketed due to a quasi-religious belief in human reproduction as the highest possible good. Most of the action occurs in a massive three-kilometer high city-tower called Urban Monad (Urbmon) 116. Most of humanity lives in these mammoth thousand-floor skyscrapers arranged in "constellations", where the shadow of one building does not fall upon another. The population is supported by the conversion of all of the Earth's habitable land not taken up by Urbmons to farmland.
• Discussed in Stand on Zanzibar (written in 1968, set in 2010). With the world population reaching seven billion^note  one of many surprisingly accurate predictions in the book, society is definitely beginning to feel the stress of the huge population, but, as pointed out in the comment that gave the book its name, you could still fit them all, standing shoulder to shoulder, on the island of Zanzibar.
• In The Starchild Trilogy by Frederik Pohl and Jack Williamson, the population of Earth has reached the thirteen billion mark.
• Kris Longknife: The sequel series starting with Emissary reveals that the Iteeche Empire's core worlds are insanely overpopulated and has been for centuries, to the point where the Imperial planet's sea level has dropped by an amount visible from orbit due to. The Imperial Planet alone has roughly 150 billion inhabitants, which means living space is at a premium and, when combined with Iteeche Honor Before Reason attitudes, means life is not nearly as valued as it is by humans, at least by the noble classes: they behead people for minor offenses, their current civil war is destroying fleets hundreds and thousands of ships strong on both sides, and as we learn in Admiral, if the rebels gain space superiority over the Imperial Planet, they'll nerve gas the whole thing from orbit and resettle it with their own civilians to try to erase any trace of the preceding dynasty (this has happened at least four times in the past).
• Several of the short stories collected in "Welcome to the Monkey House" by Kurt Vonnegut (including the titular story) involve a future where the population of Earth has reached over 17 billion and suicide is actively encouraged by the government.
• While never outright stated, Red Queen implies that this is what becomes of the world in the distant future. In the third book, King's Cage, Mare reads a journal mentioning the Lakelander War, which killed 500 thousand Silvers and 50 million Reds, with twice that number of the wounded (so in total more than 150 million people affected). The war involved Norta, which covers the Northeastern United States, and Lakelands, which covers the East Central States and Canada east of Lake Superior. The total population of those regions is, as of 2016, less than 130 million. And this happened after another catastrophe struck the world, which presumably submerged New York and other areas and led to the dearth of space to live on.
• Italian sci-fi novel Le meraviglie del Duemila ("The marvels of 2000"), written in 1907, predicted that by the early 21st century population increase would need a revolution in food production (e.g., most food coming from the sea) to feed everybody. The world population predicted for the year 2000 was a whopping... wait for it... 2.2 billion people, or about 1/3 of what the actual population would be. To be fair to the author, the prediction was consistent with the growth rate observed in the 19th century^note Human population grew 50% between 1800 and 1900, from one billion to 1.5 billion people; a population of 2.2 billion is very close to a further 50% growth... it's just that Real Life was bolder than his imagination.
• In Larry Niven's Known Space setting, Earth has a population of eighteen billion in the age of Beowulf Shaeffer, and societal rules have adapted accordingly. This is dwarfed by the Puppeteers who, as we find out in Ringworld, have a population of one trillion — although this is a couple of centuries after Beowulf's setting. The Puppeteers' absurd population is a significant problem for them, and required them to terraform four other worlds to serve purely for food production while repeatedly moving their planet away from its sun to manage the immense amounts of waste heat that they produce.
• A variation set in the past occurs in The Deadly Mission of Phineas Snodgrass, Frederik Pohl's parody of Lest Darkness Fall and other Giving Radio to the Romans stories. Phineas Snodgrass time-travels to Ancient Rome to introduce modern medicine early. This results in a population explosion that breaks 20 billion by the year 200, a quarter trillion by the year 300, and people calculate that by 1962 (the year the story was written) the whole mass of Earth would be made of people. The solution to overpopulation is to invent time travel and kill Snodgrass before he can "help" the past.
• In The Eleventh Commandment by Lester del Rey a secret agent of the (human) Martian government visits Earth, which is ruled by a universal Catholic Church, already has a population of more than 11 billion, and is exhorted to have more— contraceptives are forbidden. The agent attributes this to religious prejudice, but discovers that the Church knows that an atomic war in the past can threaten the destruction of the human race through mutations unless they breed enough to swamp it out.

Live Action TV

• In the Doctor Who story "Colony in Space", Earth's population in the 25th century is said to be one hundred thousand million (or one hundred billion).
• In the Outer Limits episode "Demon With a Glass Hand", we learn that by 2964 Earth will have 70 billion people.

Tabletop Games

• Warhammer 40,000: Hive cities often reach the tens of billions in population, the vast majority of which are impoverished scavengers feeding on the refuse of the upper atmospheric spires where the nobility lives. The Imperium of Man even outright states in regards to its Forever War with the rest of the galaxy: "We count the lives of planets, not men" — implying the Imperium has grown so vast the population changes so rapidly that when you finished counting, you'd have to restart again — and a callous disregard for the individual humans they send into the meatgrinder.

Video Games

• Escape Velocity: Nova: All the Auroran capital worlds have populations in the high tens of billions (Heraan approaches 90 billion residents) stuck in large Arcologies due to industrial pollution making the surface uninhabitable.
• In StarCraft, Earth's population is around 23 billion by 2301.
• In Galactic Civilizations a planet's population is limited only by the number and quality of farms can be built on it. Earth has a potential population of 50 billion. Colony Ships and troop transports transfer population in units of a million, and the basic ships can carry 500 of those units.

Web Comics

• Schlock Mercenary:
  • The Sol system has a population greater than a trillion in the 31st century, Earth alone hosts 200 billion people, 4.62 billion of whom are concentrated in the capital megalopolis of Dom Atlantis. The footnote explains that plentiful energy, cities measured in cubic kilometers, and hyper-advanced "agriculture" mean that they can fit all these people while taking up less than ten percent of the planet's surface, including the seas.
    Footnote: There are other ways to fit 200+ billion people on a planet, but this is one of a very few ways to pull it off while still having it be useful as a planet.
  • The Espererin home system is said to be home to uncounted billions of espees. The narrator adds that they are literally uncounted.

Web Original

• Discussed by Isaac Arthur, who points out that most settings actually invert this, having populations that are far too low in comparison to the total amount of potential living space, some examples being Trantor and Coruscant. Mathematically, if Earth's land area were completely covered in one city and each person had a generous 10,000 square feet/929 square meters, you could fit 546 billion people on Earth without stretching resources. Scale that up with fusion power, towers reaching all the way into space and subterranean settlements, and you can actually fit a quadrillion people on Earth, and do so without causing Gaia's Lament, since you can also have plenty of room for country-sized nature preserves. The only real limiting factor on a planet's population is the waste heat generated from all those people, which could also be dealt with given the right technology.
• Played with in Orion's Arm. The population of "baseline" (not substantially genetically modified) humans falls from 15 billion to 2 billion between 2400 and 2900 A.D., and are considered an Endangered Species in the very far future (c. 10,000 - 20,000 A.D.). However, in that same far future, our genetically modified descendants number in the hundreds of thousands of billions.

Western Animation

• In one episode of Futurama, it is mentioned that the population of Earth in the year 3000 is 40 billion.

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