Flooded Future World

I've been to the year 3000
Not much has changed but they lived underwater

— Busted, "Year 3000"

A time in the future where, for whatever reason, the Earth has become entirely or partially flooded by rising seas.

This kind of setting can be brought about by various reasons, although most involve some kind of natural or unnatural disaster. In modern fiction, this often takes the form of a Green Aesop about Global Warming, as potentially catastrophic rise in sea levels are a very real danger of greenhouse conditions melting the polar ice caps and sending their meltwater into the ocean. In more fantastical settings, this may occur in the wake of The Great Flood if the waters never recede.

The severity of the flooding often varies between works. More downplayed examples restrict the flooding to coastal areas and plains; these may become great drowned morasses or be entirely covered by wide shallow seas, leaving highlands and mountains above the waves, although usually still humid and swampy. In more extreme examples the entire planet can become covered by a pole-to-pole ocean, occasionally with a few islands poking through to mark the peaks of mountain ranges. However, works employing this angle tend to exaggerate the extent to which this can occur — if all the ice on the planet were to melt, this would "only" release enough water to flood most coastal plains and lowlands; covering all continental masses would require a lot more water than exists on Earth today, liquid or frozen alike, and while there have been times in the distant past when Earth's ice caps melted completely — most of the Mesozoic, for example — there was still plenty of dry land.

In more downplayed settings, humanity may be able to scrape along in the drowned lowlands, sometimes inhabiting the higher reaches of buildings or natural formations poking above the waterline, or may retreat altogether to higher ground. Sometimes, civilization might endure under a sort of natural siege, relying on elaborate levees and seawalls to preserve itself. In the most intense cases of global flooding, survivors will often be forced to live on rafts, ships, and other waterborne vehicles drifting along the currents, although luckier sorts may be able to hold on in a City on the Water or an Underwater City. Either way, humanity will likely develop into highly nautical societies. Survivors will typically have to deal with intense resource scarcity, since all the stone and metal and forests are at the bottom of the sea, and remaining artifacts and technology will be rare and precious commodities. This often leads to a full-on Scavenger World if they come to rely on gathering flotsam or diving to submerged ruins for artifacts and materials. Particularly unlucky ones might also get Sea Monsters in the bargain. In cases where islands or other emerged lands exist, they'll either be the main refuge of society or semi-mythical promised lands that the seabound survivors yearn to find.

A Sunken City or several is a common visual element. Depending on the severity of the flooding, these may be present as mazes of half-drowned buildings along the coasts, sometimes draped in plant life or inhabited by Disaster Scavengers, or as fully submerged ruins on the ocean floor.

Subtrope of After the End, Global Warming, and Single-Biome Planet. In regards to Apocalypse How, these events are of planetary scale but their level of disruption varies between works. Remaining civilization may be prone to Ocean Punk.

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Examples

Anime and Manga

• Agent Aika: In the future, disastrous earthquakes have caused most of the Earth's land to sink under the sea. As this has left a great many cities and treasures underwater, divers known as Salvagers make a business out of diving to the bottom of the ocean to recover these things.
• Blue Submarine No. 6 takes place after the apocalyptic flooding of Earth by Emperor Scientist Dr. Zorndyke, with the few remaining cities ravaged by his army of half-human Fish People, his "children" and intended heirs to the new world.
• Daphne in the Brilliant Blue is set hundreds of years after the planet was flooded by global warming, and the only remnants of humanity are the descendants of several underwater cities that resurfaced and colonized the remaining landmasses. Siberia is now a tropical vacation paradise, and virtually all transportation is submersible or seafaring to some degree.
• Ekrano takes place in a future where the Earth is covered in a global ocean infested with sea monsters called Kujirani.
• Future Boy Conan is set after geomagnetic weapons shift the Earth's crust such that the oceans have flooded the world. The bad guys live on an island that's the sole surviving industrial center on the planet, and even they are forced to scavenge from the ocean floor. The Earth's plates are still shifting two decades after the weapons were last used, causing Industria to sink but a new continent/island to be formed.
• Gargantia on the Verdurous Planet is set in the distant future, where the Earth has turned into a giant ocean without a single piece of land above water. Humanity survives by pillaging sunken ships and submerged ruins and connecting dozens to hundreds of ships to enormous fleets such as the eponymous Gargantia and coexists with the powerful, intelligent Whale Squids that also inhabit the future oceans.
• Neon Genesis Evangelion: When Adam was awakened in the middle of Antarctica, kicking off the Second Impact, a "ripple" almost a quarter-mile (four-hundred meters) tall in places spread outward, wiping out every coastal city in the southern hemisphere and resulting in a lot of underwater real estate.
• Patlabor: The Humongous Mecha were originally developed to construct barrier dams to protect coastal cities from being flooded due to climate change. Downplayed, as the flooding is not catastrophic and is merely part of the background.
• Yokohama Kaidashi Kikou: Due to an environmental shift whose details are largely unrevealed, sea levels have risen dramatically, submerging a great many coastal cities completely and rendering many roads and highways partially to completely impassible. In ch. 44, Director Alpha remarks to her assistant that this process is still ongoing, noting that towns and cities sometimes suddenly disappear. They themselves have escaped this fate, but can only passively observe as they're stuck on a huge airship in the upper atmosphere that can't land because there's nowhere safe for it to do so anymore.

Comic Books

• Drowntown: Future London has become a City of Canals, thanks to climate change. Among other things, the flooding means that water-based transport is now considerably more common — one of the main characters is an aqua-courier, riding through what used to be streets.
• Give Me Liberty: In the future, rising sea levels have turned the streets of New York City into Venice-like water canals.
• In The Jetsons comic book adaptation, the reason the family lives in the sky is due to flooding. This isn't the case in the cartoon it was adapted from, where we see the surface and it looks fine.
• Ultron Forever: In the future where Danielle Cage is the new Captain America, New York has been flooded and Dani protects it from pirates and scavengers.
• Valérian: "The City of Moving Waters" takes place in a flooded New York City after a nuclear explosion melts the poles, in the near future of 1986 (the story was written in 1971).

Fan Works

• After the Centre: Despite efforts to curb global warming, the situation is still bad enough that London is compared to Venice, with people now having to navigate with boats.
• Wet Equestria: The world was flooded by a sudden and unexplained rising of the waters, where rivers, lakes and seas simply began rising ceaselessly without apparent cause, eventually covering all but the highest mountaintops. Former centralized countries no longer exist, and ponies survive in a scattered system of domed seafloor towns, fortified holdfasts on the mountain-islands, and nomadic flotillas or solitary boats wandering the oceans.

Film — Animation

• La Maison en Petits Cubes transpires on an Earth that's mostly seawater. The level rises steadily, as the main character discovers one morning while getting out of bed when his feet get wet in inch-deep water on his floor. The solution is to build another room atop his current room, which he has done five or six times previously. There are a few other people that visit him, always traveling by boat, which is also how the man acquires his building materials.
• Weathering With You: Downplayed, as the film is set 20 Minutes into the Future, but Tokyo is steadily becoming more and more flooded until it is completely submerged by the end.

Film — Live-Action

• A.I.: Artificial Intelligence: The backstory has climate change destroying Earth's ecosystems and causing sea levels to rise by a hundred meters. Most of the Third World is effectively uninhabitable, while the rich nations managed to use their advanced technology to survive.
• The Day After Tomorrow: A climate change catastrophe causes New York City to flood. Then the falling temperature causes the flood waters to freeze over.
• Last Sentinel (2023) takes place in a future where Global Warming has reduced the landmass to only two continents which are at war with each other over what little remains of land and resources.
• Reminiscence: In a dystopian near-future, global warming has resulted in extreme temperatures that forces society to live by night and the world is steadily flooding due to rising sea levels.
• Split Second (1992) takes place in (then-) 20 Minutes into the Future (in 2008), after the melting of the Arctic ice raised water levels around the world. The movie itself is set in a partially-flooded London, large portions of which have had to be abandoned to the rising waters.
• Star Wars: The planet Kamino, home of the cloning facilities of the Republic, was flooded by melting glaciers in the distant past. The Kaminoans survive on cities raised by pillars above the eternally stormy ocean that now covers the planet.
• Waterworld is the Green Aesop version, created when runaway global warming floods the entire planet. Humans mostly inhabit "atolls", ramshackle floating villages built out of whatever junk and flotsam could be scavenged from the sea, but there are also Drifters who spend their entire lives sailing nomadically between villages on one-person boats, aquatic mutants with gills behind their ears, and the Smokers, feared pirates with access to the only remaining motorcraft. There are also mutant sea monsters in the oceans, and food plants and soil have also become rare and valuable luxuries. Myth claims that a single piece of dry land remains, and most of the movie follows a hunt for this island. In the end, it's revealed that the island exists — it's the tip of Mount Everest.
• The World Sinks Except Japan: Climate change has made the sea levels rise so much that every landmass in the world has sunk... except Japan.

Literature

• Arctic Rising (and its sequel Hurricane Fever) takes place in a warming near future where the Arctic Circle is melting, the Northwest Passage is a major shipping corridor, and Caribbean islands like Anegada sink beneath the waves forever.
• Conciencia y Voluntad takes place 20 Minutes into the Future, where runaway climate change has sunk all coastal cities — the walls around La Plata are partly to keep the waters at bay, and partly to provide cover against the roamers of the ruins of sunken Buenos Aires.
• Dark Life: After the ocean has raised and washed away the Earth's oceanfront property, the only land available is on the bottom of the ocean. Determined Homesteaders in underwater farms have to battle pirates, a corrupt government, and in the case of some of the characters Fantastic Racism from being born with superpowers.
• Drowning Towers (or The Sea and the Summer) by George Turner describes a future in which Melbourne is partially submerged in water. As the tops of skyscrapers are above the water level, they are still inhabited by the cities' poorer classes.
• The Expanse: Climate change has resulted in many coastal buildings getting lost in the water. While those in space are killing each other over water, Earth is practically drowning in it.
• Flood and its sequel Ark center around the transformation of the Earth into an ocean planet due to the release of massive reservoirs of water from within the Earth's mantle. Humanity on Earth survives mostly on massive rafts and ships and in a single underwater city, although in Ark there's talk of genetically engineering an aquatic human species.
• The Kraken Wakes depicts unseen aliens colonizing the Earth's oceans, and eventually melting the icecaps to cripple human civilization. The bulk of the novel is set in England, and the reader witnesses London becoming mostly submerged and abandoned.
• The Gregor Mandel trilogy by Peter F. Hamilton is set in a Global Warming Britain with housing shortages due to coastal evacuation and a lot of arable land turned to salt marsh, made worse by the inefficient Communist government which used to run the country — Greg notes that building levees is among the oldest form of civil engineering.
• The Maze Runner: In the backstory, a Solar Flare Disaster has melted the ice caps. Mark's flashbacks in The Kill Order feature him living in a skyscraper after the city was flooded with scorching water.
• Moojag and the Auticode Secret: Most of England has been underwater since the tidal surge caused by global warming ten years ago. Nema and her friends live on a small island in what used to be Surrey.
• New York 2140: In the titular year, the Big Applesauce has become a City of Canals not unlike Venice due to climate change.
• Star Carrier: Climate change combined with a couple Colony Drops has caused much of the low-lying east coast of North America to become flooded, to the point where it was necessary to move the capital of the United States of North America to Columbus, Ohio.
• Vorkosigan Saga: The stories are set far enough into the future that sea levels have already risen; London is protected by a system of barrier walls.
• The Windup Girl: This is a major background element and plot point. The novel takes place in 23rd century Bangkok, which is actually below sea level after climate change has taken its toll and only survives thanks to enormous sea-walls and powerful pumps that work throughout the monsoon season.

Live-Action TV

• The Expanse: Earth has experienced significant sea level change. Several shots of the opening credits show time lapse images of melting glaciers and sea walls being constructed to protected Liberty Island and the rest of New York, which also shows up in several episodes as part of their establishing shots.
• The 2003 The Future is Wild miniseries has this happen in the "100 million years from now" segment. Earth has a hothouse climate, with shallow seas covering most of what were once valleys and lowlands.
• Life-Force: Most of Earth is said to have been flooded by the ice caps completely melting in the series, which takes place in 2025. The effect this has had on the United Kingdom is particularly depicted, with the opening credits and first episode showing that the south has been completely submerged via a map graphic, and all subsequent episodes taking place on the collection of islands that remain in the north. One episode in particular even uses a sight gag showing the Blackpool Tower protruding from the sea...
• Sliders: One alternate Earth features a San Francisco that's inundated by water, leaving the Sliders team clinging to the unsubmerged tip of the Transamerica Pyramid as a refuge from sharks.
• Star Trek: Deep Space Nine: In "Our Man Bashir", this is the goal of James Bond-esque villain Dr. Noah — flood the Earth and wash away humanity, save for a few survivors at Noah's facility on Mt. Everest who will become a new human race.

Tabletop Games

• CATastrophe is a Cosy Catastrophe setting created as a collaborative effort on /tg/. It's the future, humanity has gone extinct and the sea levels have risen, leaving only semi-submerged ruins and small islands which are roamed by Cat Girls.
• Cerulean Seas: An unknown event caused a global flood that covered most of the world in water and swallowed the cities of the drylanders, leaving the game's current setting dominated by scattered islands and vast seas.

Video Games

• Anno Domini: Anno 2070 is set in a post-sea rise Earth to justify the franchise's core gameplay concept of settling remote islands within a futuristic setting.
• Battle Engine Aquila takes place after rising sea levels submerge almost all livable land, leaving only thirteen islands that the survivors war with each other over.
• Brink!: 20 Minutes into the Future, global warming and rising sea levels have rendered most of the earth a giant ocean, with the Ark, a City on the Water built before the flooding, and a few mountaintops as the only known places where humans survive. The Ark itself is suffering an Overpopulation Crisis due to holding nine times as many people as it was originally designed to host, leading to resource shortages, severe wealth inequality, resentment between the refugee community and the Ark's Founders, and eventual civil war.
• Civilization:
  • In the Civilization VI expansion "Gathering Storm", polar ice caps begin to melt and some coastal land tiles become flooded when enough carbon dioxide is released into the atmosphere from industrial buildings and units.
  • In Civilization: Call to Power, if enough pollution occurs, the sea level can rise.
• Dead Space: The Earth experienced a crisis known as the Global Warming Epidemic, which resulted in rising sea levels that destroyed cities like New York, Venice and Hong Kong. The so-called "trinity hurricanes" that now formed as a result of the warmer oceans caused further damage, eventually submerging the entire Mississippi Delta region as well.
• Dolphin Blue is set in the water-covered planet of Aquadia, where an unknown cataclysm in the past have caused the seas to cover every inch of land available. And like the title states, you spend the entire game battling enemies while riding on dolphins.
• Final Fantasy Legend III takes place in three different time periods, broadly defined as the Past, Present and Future. Thanks to an entity from the Pureland, the whole world is being flooded; the Future is so flooded that what started as two continents with a couple smaller land masses has been reduced to six small islands.
• Flotsam: The Earth was flooded over and covered by ocean by an unknown cataclysm in the recent past. The survivors either cling to the few rocky peaks that still rise above the sea or live nomadic boat cities, sustaining themselves by fishing and harvesting seaweed, collecting scrap floating in the oceans, and picking over the few ruins that still stand above the waves.
• Gadget: Past as Future is set in the dystopian, Soviet-esque Empire where scientists claim a comet will strike the Earth and annihilate everyone. Along the way, the player becomes subjected to the Sensorama which shows them visions of a greenish, swamp-like future version of the Empire that might have been the comet's aftermath. Considering the player spends half the game living these visions between the present day, it's never made clear which is real and which were Sensorama-induced hallucinations.
• Horizon Forbidden West: Much of San Francisco is at least partially flooded, with certain buildings being entirely underwater. Burning Shores reveals that not only has the greater Los Angeles area met with the same fate, but volcanic eruptions have turned the whole locale into a lava-filled archipelago.
• Hydrophobia takes place in a future where much of the world is flooded and massive ships now serve as floating cities.
• In the Hunt is set in the distant future, after the powerful D.A.S. terrorist organization unleashed a doomsday device that caused the polar ice caps to melt and flood most major cities in the world. Players assume control of a powerful prototype submarine as they battle through legions and legions of D.A.S. enemies in six underwater-themed levels.
• The Legend of Zelda: The Wind Waker: The Great Sea the game is set in is what remains of the ancient kingdom of Hyrule after it was flooded by the gods in order to protect it from Ganondorf when the Hero of Time did not reappear to save it. The islands of the sea are the highest mountaintops of the ancient kingdom, to which the people of Hyrule were forced to flee as the oceans rose.
• Mega Man Legends takes place thousands of years later in the encompassing Mega Man timeline, and the opening narration states that the world is filled with water. What few settlements left around the world exist on islands or are built over the ruins of a past civilizations, if not both. Earlier installments in the Mega Man franchise show much more landmass among the various areas of the world. It makes sense since Legends is canonically the last series in the original timeline.
• A New Beginning: One of the levels is set in a future San Francisco where the streets are flooded, so a lot of it takes place on the roofs and upper floors of buildings instead.
• Raft: In the full Steam version, it's revealed that the reason you are Lost at Sea is because of the ice caps melting and submerging most of the world. While there were some attempts to prevent this through reforestation projects, the government thought they cost too much money and spent their funding on floating cities and yachts instead.
• Shin Megami Tensei NINE: The post-Time Skip chapters take place after the massive flood that occurs in Shin Megami Tensei I. What's left of humanity lives in True Tokyo, a City on the Water ruled by the Central Administration Bureau.
• Sidewinder F is set in an Ocean Punk-type setting after melting glaciers have flooded most of the planet.
• The Splatoon franchise's backstory indicates that the game is set millennia after the extinction of humanity (and most mammals in general) due to global warming raising the seas, paving the way for various sea-life to evolve and become the new dominant species on the planet. According to the first game's official artbook, another contributing factor was the nuking of Antarctica during World War V, melting most of the continent. Either way, it is unclear just how much land actually remains in the present day.
• Submarine Commander: The Earth experienced global warming so fast that the crew of the titular submarine doesn't realize it, and when they surface, it's all sea.
• Submerged takes place after climate change has flooded the world, and is set in the remnants of a metropolis whose tallest buildings are now like an archipelago of small islands.

Webcomics

• Ennui GO! has an in-universe video game called Deluge in which the post-apocalyptic Earth is flooded and culture stuck in the 1990s.
• Homestuck: Post-Scratch Earth turns into this once the former empress of the trolls takes over and Alterniaforms it into a state more comfortable for an aquatic alien like herself. By the time her flood is done, humans are all but extinct and Earth is completely covered by oceans, broken only by floating prefab slums home to alien exiles and by Dirk's home on top of a ruined skyscraper.
• Puffer and Clarissa: The world is completely submerged, with humans living on large boats gathered together known as "ship towns".

Web Original

• 17776 uses an Establishing Shot of the Statue of Liberty chest-deep in water by the titular year; a Freeze-Frame Bonus shows major geographical changes, including Florida and Louisiana completely flooded. The epilogue reassures people that affected populations were safely relocated with future technology.
• Goodbye Strangers: In the future, the Earth is flooded in red water. Many, if not all, Strangers stopped appearing after this event. The Walltown and Infrared modules were written after this event.
• Pirates SMP: Discussed. Martyn theorizes that at some point in the future, the Ice Wall surrounding the Ecclesiae Sea will melt, causing a Giant Wall of Watery Doom that will raise the sea level and destroy entire civilizations.
• SCP Foundation: The Foundation narrowly averted one of these at SCP-2894. The site was originally an island containing an underground portal to an alien sea, which constantly expelled water into the Earth's oceans. This caused global sea levels to rise steadily, and Foundation scientists predicted that the two worlds' sea levels would only equalize well after the Earth was completely flooded by water. In the end, the apocalypse was only prevented by retroactively erasing the island and the portal from existence.

Western Animation

• BoJack Horseman: In "Ruthie", Princess Carolyn's eponymous descendant is shown to live in an underwater city with the rest of civilization after the ice caps melted and the water levels rose. However, Ruthie is Princess Carolyn's coping mechanism after her awful day; she doesn't exist, and it is all a fiction.
• Chaotic: In Season 2, the characters find a network of caves that act as portals through time, and find that in the future all of Perim is apparently under water, with something lurking under the waves. This turns out to be Foreshadowing the M'arrillian Invasion later in the season, with their ultimate goal being to cause this (since they not only survive but thrive in those conditions, unlike everyone else). Given that the M'arrilians' plan is thwarted, this has been relegated to a Bad Future.
• Water levels have risen considerably in Droners, and civilisation now thrives on various archipelagoes which are themselves at risk of being submerged.
• Futurama: In "The Late Philip J. Fry", while travelling through a long series of future eras, the characters come across one where the Earth is covered by water and roamed by ferocious sea monsters.

Real Life

• The scientists Peter Ward and Donald Brownlee on their book The Life and Death of Planet Earth cite research from NASA Ames Center that suggests it is possible that Earth would be covered again by the waters in the distant future (hundreds of millions of years from now), was plate tectonics (thus mountain building) to stop before oceans were evaporated away due to the Sun's increased luminosity as it ages.

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