WMG: Waterworld

Waterworld would've been the future of Pokémon Sapphire, had Team Aqua suceeded.
Their plan was to use Kyogre to flood the Earth.
  • Conversely, The Postman would've the future of Pokémon Ruby, had Team Magma has suceeded in their plan to use Grodoun to drought the the world.

A massive ice asteroid caused the rise in temperature and the sea levels.

The main Headscratchers about the film is that there simply isn't enough water on the planet, solution? Just add water. A large enough ice asteroid would explain why the sea level is so high, it also caused the mass extinction of most of the other types of creatures on the planet which is why we don't see many. Also maybe the asteroid contains lots of sodium to explain the salt levels in the water.
  • Ice asteroids are way too small to seriously increase the amount of water to such levels, and would be far more destructive. If the world's water levels increased by 300 meters, and we know it was more than that, then the asteroid would have to be 330 kilometers in diameter. 36600 times more destructive than the one that wiped out the dinosaurs. It would break the crust, it would cause a nuclear winter, it would produce earthquakes greater than have ever been seen in the last four billennia. It would wipe everything and everyone. Nobody could survive it.
  • Not to mention, an asteroid would probably throw up enough debris into the atmosphere to cause a new ice age, which would cause the ice caps to expand, and make the water level around the world go down.
  • According To My Calculations, in order to actually get the sea to rise 25,000 feet (which would cover all the continents except for a few mountains in the Himalayas which, logically, becomes Dryland) it would take a single comet over 2,000 kilometers in diameter. Impacts with stuff like that gets into Earth-Shattering Kaboom levels.
    • Well there goes that theory. How about a series of smaller asteroids over a longer time-span. Highly unlikely granted but this is WMG.
  • What if it only went through the atmosphere never hitting any solid or liquid?
  • What about a massive and continual barrage of ice asteroids instead of just one really huge one?

Aliens dropped off the water.
  • Maybe intentionally, maybe unintentionally by an AI terraforming craft, but instead of the extra water being deposited by comets (which are destructive), the terraforming ship picked up a few comets, melted them, added the needed salinity and pumped the water down to the surface via a temporary Space Elevator. Aliens will get here when they get here, point is Earth is stuck with more water than we can shake a stick at. (Hey, if the Battle: Los Angeles aliens can reduce the sea level in a day, then these guys can pump it up.)
    • Thorny is why we didn't fight it off. I'm guessing that the water was pumped down in such quantities and so fast coastal communities didn't have a chance, and think of how many National Capitals are near sea level, too.
  • This might explain the "whalefin" monster with its bizarre vertical mouth; no Earth fish, aquatic mammal or even invertebrate has a mouth that runs up and down. Either the aliens may be trying to rid Earth's seas of its native predators to make room for their own species, or it might have been accidentally released, the way zebra mussels were in the Great Lakes.
  • That's a neat idea - so many stories have "water looters", like in V, but this idea inverts that.
Like the above theory only worse...
Aliens didn't just drop off water, they deployed some bizarre wormhole to drain their water onto our planet to escape [[Eldritch Abomination something horrible]]. The heat of the portal's energy simultaneously melts the ice caps causing the world or at the very least those that survived to believe it was just he ice caps. Alien wildlife overtakes the ocean and somewhere deep below Waterworld is an alien refugee civilization. Various new environmental factors mutate the lifeforms left, i.e. The Mariner and anything like him.

This is in the same world as Mad Max
Australia just happened to be unharmed.

The ocean isn't global

There's whole continents still around, just nowhere near where these folks are.
  • THAT... explains quite a bit.

My theory is that the ice caps did melt, but acted as they would in real life, flooding islands and costal areas. The flooding of several nations ended up sparking a nuclear war, causing many to flee by boat. The EM Ps generated by the nukes wiped out navigation equipment and led to many people being stranded. These people would find shelter on oil rigs and large ships. The radiation would accumulate on the coastlines, because one: many large cities are costal, and two: radiation caught in rivers would eventually make its way to the coast. Anyone who acually found dry land would die of radiation poisoning. After generations passed, everyone assumed that dry land was now underwater. In reality, most of the worlds landmass still exists in various forms, from post-apocalyptic wasteland, to small villages and surviving wilderness, to rebuilt civilizations. Everybody in Waterworld are just wandering around the middle of the pacific convinced that dry land isn't real. Oh, and this explains where the pirates get their gas, ammo, and factory rolled cigarettes. They trade (or more likely steal) from land-based societies. Hell, they may even have originated on land, starting out as raiders who stumbled across an oil tanker, and discovered that there's a bunch of defenseless morons out in the middle of the ocean who don't know that land exists.
  • This might also explain the whalefin monster; a mutation resulting from nuclear radiation. Hell, even the Mariner himself has been stated in-universe to be a mutant, so we know mutants are a thing in this world.

Waterworld takes place in the Fallout verse.
  • Think about it we never actually see the oceans in fallout and the Pirates in the movie were vary Raider like. mayhep the world was not flooded completely perhaps this is happening in some god forsaken stretch of oacen between the east and west.

The ocean didn't get larger the land got smaller
Some time in the past a large part of the planet was detached possibly to make a secound moon or something similar, this cause the planet to be smaller allowing water to cover nearly the entire surface.

The Earthsea Trilogy is set in future waterworld
  • By the far, far future, maybe 5 or 10 thousand years after the film, society begins to revert back to more primitive civilizations, and had forgotten the society that came before. The magic in Earthsea is just sufficiently advanced technology.

Warterworld takes place in the same universe as A.I.: Artificial Intelligence.
During the time gap between David being trapped underwater and the world gone into an Ice Age. The robots are hiding in the remaining islands, watching the events of the movie happening.