History Headscratchers / Waterworld

** Historically, a lot of sailors on ocean-going vessels didn't know how to swim, in part because if you're thrown overboard far from land, you have little hope of finding land or rescue, and thus being able to swim just prolongs your suffering.

** A somewhat reasonable explanation (if taken with a huge grain of salt), besides the ice melting mentioned in the beginning of the movie, could be an astronomical event. Maybe some large body gravitationally disturbed the Oort Cloud at the edge of the Solar System and sent several ice-rich comets or other bodies towards the inner Solar System where Earth is. Enough of these fragments may have fallen on Earth to add water to the already rising oceans. This is actually the most accepted explanation for most of the water that Earth has: collisions against water-rich bodies in the early Solar System.

** One somewhat reasonable explanation (if taken with a huge grain of salt), besides the ice melting mentioned in the beginning of the movie, could be an astronomical event. Maybe some large body gravitationally disturbed the Oort Cloud at the edge of the Solar System and sent several ice-rich comets or other bodies towards the inner Solar System where Earth is. Enough of these fragments may have fallen on Earth to add water to the already rising oceans. This is actually the most accepted explanation for most of the water that Earth has: collisions against water-rich bodies in the early Solar System.

** One somewhat reasonable explanation (if taken with a huge grain of salt) besides the ice melting mentioned in the beginning of the movie could be an astronomical event. Maybe some large body gravitationally disturbed the Oort Cloud at the edge of the Solar System and sent many ice-rich comets or other bodies towards the inner Solar System where Earth is. Enough of these fragments may have fallen on Earth and added more water to the already rising oceans. This is actually the most accepted explanation for most of the water that Earth has: collisions against water-rich bodies in the early Solar System.

* Where did all of the water come from? If every bit of ice melted and all the water vapor in the air fell to earth, there would only be an extra 300 or so feet of water. A lot of land would be submerged, but nowhere near enough to make the remaining land a mythical place that's nearly impossible to find. Heck, the water level was high enough during the late Jurassic and early Cretaceous periods that a lot of land, especially in North America and Africa, ''was'' underwater for a while.

*** The rising waters displaced the atmosphere, so the temperature and air pressure is just about the same modern-day sea level. Centuries of waves and rain and erosion have washed up enough sand onto the rocks to form a beach. And the flooding took long enough that tropical plants and animals were able to migrate there.

** Dryland is the top of the Everest. This is shown explicitly in the full version of the ending, where they casually find the plaque commemorating the conquest of the mountain by Hillary and Norgay. And yes, the fact that it is a tropical forest with a nice sandy beach instead of a bunch of barren rocks makes no sense, but that's hardly the only nonsensical thing in the movie.

* What ''is'' the Dryland? If the water covered all the continents, shouldn't it be, at best, barren mountain tops?

** Could be that there ''was'' only one family on the island when Enola was little. Her parents died when she was still far too young to fend for herself, leaving her with only a very frail grandparent to care for her. Realizing they wouldn't live long enough for Enola to become self-sufficient, this elder used the last of their strength to set sail, heading out in desperate search of other humans who could provide for the girl after they, too, were gone. The grandparent perished shortly before their sailboat was found, ending up in the water, and the child was discovered all alone by Helen's people.

** Could be that her parents died when she was still far too young to fend for herself, leaving her with only a very frail grandparent to care for her. Realizing they wouldn't live long enough for Enola to become self-sufficient, this elder used the last of their strength to set sail, heading out in desperate search of other humans who could care for the girl after they, too, were gone. The grandparent perished shortly before their sailboat was found, ending up in the water, and the child was discovered all alone by Helen's people.

** The sheer number of possibilities is too much to go into. Just off the top of my head: maybe there was an outbreak of illness so some people left, and when the adults realized they weren't going to make it they gave Enola the tattoo as a sort of "here's where you can find her relatives". Just that there were no relatives because the outbreak killed everyone.

* Why did Enola's parents send her away from the Dryland. It would have been a much safer place for her to grow up.

** Presumably, if there ''are'' societies that willingly interbred with mutants, they interbred enough to ''become'' mutants themselves after a few generations, so no longer have the need to use boats or cluster on piddly little atolls of salvaged junk. Provided they've found a way to lick the fresh water shortage (sucking fluids out of fish? migrating north to chew on whatever's left of the polar ice?), they could have simply moved completely beneath the surface,
leaving the gill-less bigots who detest them behind to die out.