# How can water magic destroy the world?

The question is self-explanatory. In my novel, there is an evil sea goddess that wants to destroy the world. I want to emphasize that she wants to destroy the world completely, in a way no plant, animal, human being or bacteria could survive. She has water magic, what means she can control all water that already exists, but not create water out of nowhere.

I suppose she could just create lots of tsunamis or waterspouts, but that would not solve the problem completely. Some people could still survive if they were lucky. I was thinking that she could levitate an absurd amount of water(like, all the oceans) until the stratosphere an then drop everything, like a liquid meteor or something. But I don’t know if that would work.

I’m trying to avoid solutions like “dry all the water from the planet” or “poison everything and let them die of thirst”. I’m looking for something that would kill everyone in the planet in a matter of seconds, like a giant atomic bomb or something. But... with water.

Extra information:

• Since my character is a goddess, she can manipulate as much water she wants(including all the water in the ocean, rivers, lakes but not ice or snow)
• She can summon hurricanes, water sprouts and other kinds of aquatic disasters
• She can manipulate water pressure and density
• No living thing can survive the aquatic cataclysm, not even marine animals
• The world has to be completely destroyed in a mater of hours

Answer with total world destruction with least amount of goddess interference wins!

• Water's a mineral out past the Asteroid Belt. Pretty much everything solid in the outer solar system has water ice as a major component. What kind of range does she have on her "Control Water" power? Oct 6 '20 at 17:08
• Welcome to worldbuilding, please note that we don't do fishing for ideas, and stating that "the most creative answer wins" doesn't give a clear guideline for picking an objectively best answer. Take the tour and visit the help center to understand what we expect from a good question
– L.Dutch
Oct 6 '20 at 17:11
• Ah, didn't see the "Can't control ice or snow" part initially. Guess 2060 Chiron will have to stay where it is. Oct 6 '20 at 17:16
• May I suggest "Most creative answer wins!" be exchanged for "Total world destruction with least amount of goddess interference" It allows for the end result with a good method of measuring best response. Oct 6 '20 at 18:22
• can she control the water up to atomic level and make some nuclear process happen? Oct 7 '20 at 4:31

If she can “control all water that already exists,” I assume that phase changes are allowed. In this case, you have two very cool options that are almost certain to kill all life on Earth very quickly:

1. Freeze all liquid water on the planet, including that inside the bodies of living creatures. (You did say that she can’t manipulate ice or snow, but perhaps she can turn liquid water into ice?)
2. Boil/vaporize all liquid water on the planet, including that inside the bodies of living creatures.

I have no idea what these would feel like for an organism, and I kinda doubt that they would feel like anything at all, because our very mechanisms of experiencing pain are certainly dependent in liquid water in some way. So every organism on the planet might feel rather peculiar for a moment before exploding.

Here’s another possibility, if you don’t like phase changes. There’s a lot of groundwater and underground reservoirs of water all over the world, not to mention low concentrations of water molecules distributed throughout the Earth’s crust and mantle that have been subducted over the years. She could probably cause quite a stir by suddenly bringing all of that water to the surface all at once, which would essentially tear the surface of the Earth to shreds and expose a decent amount of hot rock.

• Freezing or boiling doesn't control water. It controls heat.
– L.Dutch
Oct 6 '20 at 17:32
• @L.Dutch-ReinstateMonica I beg to differ - it controls the movement of water molecules, same as creating large tsunamis/hurricanes does. Temperature ~ average kinetic energy. Oct 6 '20 at 18:19
• @Dragongeek Not if the ice crystals are intentionally grown in a way that punctures nearby cell membranes Oct 6 '20 at 19:33
• @L.Dutch-ReinstateMonica You also don't necessarily need to change temperature at all to boil/freeze water - you can do it my simply manipulating pressure, which is within the inventory of powers. Even if there is no thermal damage to the organism, life will grind to a halt with no liquid water. Oct 6 '20 at 20:09
• @DRagongeek Which is why you should boil the water instead of freezing it. Raise the temperature to 200°C, and nothing will survive. Oct 6 '20 at 21:12

# "or bacteria"

Well, that is the difficulty. Everything else can be done by having the oceans rise and roll all over the sea - this, by the way, happens in Agatha Christie's The Hound of Death and should be in your Goddess' power:

He who would have been the next Guardian of the Crystal was bidden to act. That the old might die, and the new, after endless ages, might come again, he loosed the Hound of Death upon the sea (being careful not to close the circle), and the sea rose up in the shape of a Hound, and swallowed the land utterly.

But bacteria? There is almost nothing, except thorough neutrino irradiation of the whole planetary mass, that would kill all bacteria. Even a hydrogen fusion explosion in the sea would not kill bacteria more than 2-300 meters from ground zero, since water would screen the heat and the radiation.

To kill the bacteria, you need to take control of the water they contain, and e.g. make it either coalesce, or shape like a snowflake or a spiked drop. Or two semilunar blades, and then rotate them half circle in opposite directions.

This will kill all life at a cellular level, destroying their cellular walls. Plants, animals, bacteria down to Archaea. Even tardigrades would die: they can survive a complete, orderly desiccation, but unless they were already desiccated (and therefore had no water to wreak havoc in their insides), the water blades would rip them apart just as well. The cutting would kill even Gracilicutes, who ordinarily can survive a rupturing of what passes for their cell wall.

Of course, this requires an almost infinite control capability and awareness; the goddess must be aware of, and control, almost every single water molecule on the planet simultaneously.

• Agree you'd need great awareness to determine what water molecules to affect, but you'd have to actually control a surprisingly small fraction of the planet's water. The total biomass of the planet Earth is about 550 million tonnes (carbon weight), while the mass of the oceans is around 1 billion billion tonnes. Even assuming organisms are, on average, 99% water, you could control all the water inside the entire biomass of the planet and still leave 99.99999% of the world's water untouched. Oct 6 '20 at 19:30
• Even "swallowing the land utterly" would not just spare the bacteria - most life in the sea would be perfectly fine as well. Sure you'd have beached whales and fish etc. all over the land when the flood receded, but the vast majority of sea life would be unaffected. Oct 7 '20 at 13:51
• @DarrelHoffman Freshwater life, on the other hand, would be wrecked. Trouts would take the longest - they can live just fine in saltwater, but they'd no longer have suitable breeding grounds. Oct 7 '20 at 17:57

The only easy way to kill bacteria with water is heat. Which leaves the question: How does a godess heat the water without being a godess of heat?

The answer is simple: By supplying the necessary energy to the water. The godess simply accelerates a single drop of water per cubic meter of sea water to relativistic speeds. See the what-if on a relativistic baseball for a writeup of the possible effects of this. Your godess can scale the effect to whatever she sees fit, simply by changing the actual speed to which she accelerates the water drops. Once the relativistic drops collide with the surrounding sea water, they will dissipate their energy, and effectively heat the sea to an arbitrarily high temperature.

This method is

1. Fast. Basically all water bodies simultaneously explode into either a cloud of high pressure water vapor, or directly turn into a seething hot, dense plasma. It won't take long for the resulting atmospheric shock waves to level everything on dry land, before the water vapor arrives to displace the breathable atmosphere.

2. Global. With sufficient energy, the entire atmosphere can be blown off the planet. And even if you let parts of the atmosphere stick around, the entire surface of the earth will be heated to lethal temperatures by the condensing steam. This can easily heat every bit of earth's surface to 200°C, which will effectively disinfect the planet.

3. The nuclear option. This does not just look like an explosion, it is an explosion. An explosion that makes the worlds nuclear arsenals look like mere toys.

### Removing water and osmosis

All known life depends on water. It is simply too useful. You can do two things to kill all life. A combination is most likely to succeed.

• Remove water.

Removing water will kill nearly all multicellular life on the planet. They'll dry out and get irreparable damage in minutes and die off quickly if it didn't kill it outright. Simply have water remove itself from most creatures. Drying out might kill most multicellular life and a good chunk of single cellular life, but there are those that can survive a long time dehydrated. An example of multicellular life is the Tardigrade. These are tiny multicellular creatures that will go in a special sort of hibernation mode to survive, sometimes even up to 30 years. This hibernation mode might require not a too sudden loss of water, but some animals might survive.

• Osmosis.

The second one is possibly more dangerous. That is why osmosis is your secondary measure. Instead of drying out, you infuse the cells with more water. Only a few organisms are build to prevent osmosis from absorbing too much water, namely plants, so the cell can't get too much water and simply pop, destroying the whole cell. But if you force it in a cell, it'll kill the most hardy cell by simple physics. Too much pressure on the cell walls. By drying out all the life that is not able to survive drought you have enough water to kill all the rest if there wasn't enough water in the air.

So in short: leave the cells dry and pump them to bursting. If life survives for more than an hour I would be surprised.

• +1 I came here to mention the 'remove all water' option. Oct 7 '20 at 3:35
• Considering the question specifically asked to avoid solutions like “dry all the water from the planet”, I think this answer would benefit from explaining why you think there is no way around doing this.
– Mark
Oct 7 '20 at 12:35
• @Mark I'm not drying the planet, I'm drying the living organisms. If this isn't allowed, the pumping of water into the cells is enough to kill everything anyway. Oct 7 '20 at 13:16

To give another spin on the "boil all the water". If the goddess can't insta-boil everyone, but still can control evaporation and clouds/rain, she can start turning more and more of the oceans into clouds, while preventing the water from condensing back. As water vapour is a potent greenhouse gas, at some point thing will keep going on their own, and the runaway greenhouse effect will turn Earth into something like Venus. Whether there is life on Venus or not, no current Earth life would be able to survive in such conditions, and the change would be probably too rapid for any bacteria to adapt. Even tardigrades have no chance in 900°C.

• Not to mention that, if you could keep up global rain and cloud cover for even a few weeks, it would kill most crops. Oct 7 '20 at 19:05

All your waterbender goddess needs to do is dropping all of the world's water at once.

The asteroid that killed dinosaurs had its mass estimates between 1015 and 4.6 $$\times$$ 1017 kg. The oceans on Earth have a mass estimated at around 1.34 $$\times$$ 1021 kg (about 10% of the mass of the Moon).

Now sure, the space rock came at bat outta hell velocity. But the oceans are at least 5,000 times more massive, and when all that falls back from the stratosphere, it will cause damage in interesting ways.

Randall Munroe calculated what would happen if 6 $$\times$$ 1011 kg of water fell of the sky as a single droplet. This is his verdict:

The wall of water expands outward kilometer by kilometer, ripping up trees, houses, and topsoil as it goes. The house, porch, and old-timers are obliterated in an instant. Everything within a few kilometers is completely destroyed, leaving a pool of mud down to bedrock. The splash continues outward, demolishing all structures out to distances of 20 or 30 kilometers. At this distance, areas shielded by mountains or ridges are protected, and the flood begins to flow along natural valleys and waterways.

The broader region is largely protected from the effects of the storm, though areas hundreds of kilometers downstream experience flash flooding in the hours after the impact.

If you did the whole oceans instead, you'd be using 5 billion times more mass. At the very least you would kill all plant and animal life on the planet. Also bringing all that water up, then down will first cool it very fast, then boil most of it, so no microbes should survive either.

• I find it highly unlikely that this method would be able to get every single organism. Certain extremophiles are very tough to kill and can survive nukes and the vacuum if space. Oct 6 '20 at 19:29

Increase internal water pressure and watch all living things explode.

All living things contain water, and all have some variety of cell membrane that separates the inside of the organism from the outside. The goddess simply needs to increase the water pressure of all water inside living organisms. The cell membranes will not be able to withstand the massive physical stress, and will rupture very rapidly (this is called osmotic lysis). With a watery pop, all life on earth is extinguished.

Make Water Non-Polar

If your goddess can alter water chemistry she could make it non-polar, this would mess up the chemistry of all life forms as an awful lot of molecules will no more be soluble in water and suddenly fall out of solution thus rendering impossible practically every biochemical reaction, not to mention the precipitated solid inside animals blood vessels causing embolism.

EDIT: I just realized that this would probably also prevent the lipoproteins in the cell membranes from functioning properly thus dissolving all cells at once

• Yeah, remove solubility and life goes poof. +1 Oct 8 '20 at 15:30

The "even bacteria" constraint of the question is rather restrictive but here goes:

• Dissociate water in all living things back into hydrogen + oxygen. The resultant chemical reactions destroying cells would be fatal to all cell based life on the planet very quickly.
• Dissociate water everywhere back into hydrogen + oxygen. This results in a tremendous blast as every bit of water on the planet flashes into gas and then a second blast as the hydrogen + oxygen mixture ignites.
• If nuclear manipulation is allowed, change all water to heavy water, which throws off cellular chemistry, killing off higher lifeforms: https://en.wikipedia.org/wiki/Heavy_water#Effect_on_biological_systems.
• Trigger nuclear fusion of the hydrogen in water to blow the planet to bits instantaneously.

If you want something more plausible are willing to relax the constraint on being instantaneous, I'd suggest blanketing the world in heavy, reflective clouds. In the short term, the result is effects similar to nuclear winter: https://en.wikipedia.org/wiki/Nuclear_winter#Consequences and the longer term effect is the planet cooling to resemble something like Pluto.

Destabilize the orbit of earth by shifting all the water to one side

This may take a little extra magical handwaving, but I thought I would throw it out there.

According to this Quora question, the oceans make up about 0.022% of Earth's weight, and the oceans are 97% of the water on Earth. So with lakes and rivers, that's about 0.023% of Earth's weight.

That doesn't sound like much, but maybe shifting it all to one side would destabilize the orbit enough to send it spiraling into the Sun.

If that seems to slow, maybe it's just enough to turn an asteroid near-miss into a direct hit, causing a mass extinction. The survivors would then spiral into the sun.

• "Spiraling into the sun" doesn't happen without another force acting (or gravitational wave emission, but ain't nobody got time for that on the planetary scale). To get the Earth to fall into the Sun, you need to change its orbit to put its perihelion below the surface of the Sun, and that's difficult. In fact, it's easier to make Earth escape the solar system entirely. Oct 6 '20 at 22:30
• I like it, a reverse tide. Move the water around to tug at the moon instead of vice versa.
– bta
Oct 7 '20 at 19:48
• Ahh, i didnt even think of trying to get the moon to collide. Oct 7 '20 at 19:59
• @bta The original question makes it seem like she's in a bit of a hurry, and wouldn't want to take a few billion years manipulating the tidal bulge to crank the Moon back in. Oct 7 '20 at 20:23
• @notovny - I didn't do the math, but I'm willing to bet that you could cause problems much faster than that if you were trying. Not normal-strength tides, but rapidly moving the entire mass of the oceans to a single, high-altitude point to shift the Earth/moon system's barycenter. Less gentle tug, more yank.
– bta
Oct 7 '20 at 20:50

Taking inspiration from oil fracking, your goddess can manipulate and twist the water into extreme high pressure and then drilling into the earth core.

With thousands of events happening in strategically planned waves (for ultimate destruction) all over the world, it would literally be armageddon with very little warning; and no-where safe to run. Not only does that expose the surface to contaminates such as oil, but also will causes the tectonic plates to shift and will eventually expose a path for hundreds of volcanoes to erupt.

Focusing on the deep trenches in the Pacific Rim; triggering a chain of volcanoes could cause massive tsunamis which could be increased in acceleration and power before they hit land. This would generate huge 300+ ft waves causing destruction for 30+ miles inland and wiping out coastal communities.

Even the polar caps would be affected with most of the snow melting contributing to sea level rising and flooding. Enough lava flows and even the oceans could evaporate into steam or change chemistry (increased salt content and contaminates) and temperature enough that sea creatures could no longer adapt and survive.

The atmosphere would be a pervasive fog, with any condensing water on the surface cycling back into drilling more and more deeply.

All drinking water would be contaminated.

Plants would be initially destroyed by the ocean floods and the heat and toxins from volcanoes.

Light and heat from the sun would be dissipated to the point where plants would struggle to survive.

CO2 in the air would be so excessively out of balance that animals would struggle to breath.

Possibly the water vapor in the atmosphere would be too much pressure and the ozone pops like a bubble.

Sure, the would be a lot of effort for your goddess, but it would be spectacular.

# Ice-9

When I saw this question, I immediately thought of Cat's Cradle by Kurt Vonnegut.

In the novel, a scientist creates a novel form of ice which freezes at temperatures above 0 degrees Celsius and acts as a seed crystal when in contact with liquid water.

Ultimately, this results in the end of the world when the crystal is accidentally dropped into the ocean. The world almost instantly becomes a hot, dry wasteland as all liquid water is locked up in this new form of ice. It affects people & animals too - contact with the crystal with bare skin results in all the water in your body crystallizing.

If the goddess can convert even a small amount of liquid water into Ice-9, this will do exactly what you want.

I’m kind of answering narratively rather than scientifically, so I am using exactly 0% of my physics degree to suggest:

# Fire from water

About 0.03% of the hydrogen atoms in Earth's oceans are a bit heavy, and we can presume that this goddess can feel this stuff and collect it. With a bit more technology, one can assume that she can find ways to irradiate yet more of it to make tritium and then contemplate a deuterium-tritium nuclear reaction on a truly massive scale. Presumably this would be a massive underground chamber hollowed out deep, down into the crust, by erosion with water, followed by getting a cult of humans to do some necessary refinement steps with the water given, followed by storing this deuterium and tritium in that underground chamber under that great pressure.

The goal would be to ignite all of this deuterium-tritium fuel at once in a massive fusion burn which would easily dump far more energy than any known extinction event into the Earth's crust, hopefully rapidly liquefying the Earth back into a blob of hot magma orbiting the Sun, as it was in its earliest days.

Split the water in hydrogen and oxygen. All at once, if you want to be extreme. That alone would destroy all life on the planet.

• The only thing missing is one small spark to set it off. Oct 7 '20 at 18:10

# A giant atomic bomb, but with water.

The goddess has the ability to "Manipulate the water pressure and density" if she does this with just the water in the oceans and manipulates that water to have a pressure and density similar to the conditions found in the center of the sun, then all that water becomes a giant fusion bomb. This is exactly what the OP wants.

Note: She releases her influence to "set off" the bomb.

## Blot out the Sun

1. All* life on earth depends on the Sun for energy and warmth.
2. Ice reflects light well
3. Your goddess can control water / ice.

Create very thick layers of clouds in the upper atmosphere. Certain levels of the atmosphere are very cold - this is where you want to put the clouds so they naturally form ice within them.

Volcanic eruptions have lowered the worldwide temperature by several degrees for long periods of time, and these eruptions certainly don't block all sunlight.

If your cloud layer covers the entire sun-facing side of the planet, and reflects 90% of the incoming light, I would expect the entire planet to be a frozen hellscape within minutes, and dead within days.

You have massively changed the energy balance of the planet, and it will rapidly radiated its stored heat away.

[*] Ok, some life gets heat from deep sea vents, but I expect this would get them too, as the seas freeze, and oxygen exchange stops.

• Ok, some life gets heat from deep sea vents, but I expect this would get them too, as the seas freeze, and oxygen exchange stops. Just a guess, but I think it's possible a community around a deep sea vent doesn't depend on oxygen or anything else from above. The vent area, even if enclosed by ice, may be self sufficient. OTOH I believe vents don't last for millions of years but rather stop here and start somewhere else, so not clear how life would make it to new vents if the ocean were mostly frozen. Oct 9 '20 at 1:40

Bullets!

She could just use a large sea body to create many droplets and then accelerate them as kinetic projectiles to anything she want to kill. Accelerated water cuts through metal.

A mind-intensive solution, but no need to control internal water of living organisms.

## More hardcore solutions

She can manipulate water pressure and density

If she increases the pressure enough to get the water's nuclei close enough, she can create thermonuclear explosions.

If she increased the density enough, she can create a black hole.

# Hold all water still

In order to provide the solution with the least amount of interference, the solution is not allowing water to move. Including all water within organisms.

All life is dependent on water to be the medium by which chemicals and other things are transported. If the water stops moving, everything dies. Simple, efficient, and deadly. But not incredibly dramatic, all life just stops, the end.

At sufficient velocity...

Assuming energy is not at all a limitation.

Any option that doesn't kill the bacteria often hiding kilometers underground is insufficient — we need full crust destruction for this to work. So whatever approach accomplishes this with the least amount of water manipulated will be the best, because it'll be simplest to target and execute. "Destroy every cell" might be too hard to coordinate.

Suspend single drops (microliters, really) of water in the air spread out evenly over the Earth — maybe ten or fifty kilometers apart — and ping them towards the ground at, say, c minus one attometer per second. Each (upon immediately plasmizing on contact with the air) detonates with the energy of the Chicxulub impactor, gouging hundred-mile craters that overlap each other thanks to their proximity and melt the crust below them, spraying chunks of mantle into space for good measure.

If the effectiveness of this approach is in doubt, speed up the water more. Penetrate the Earth with plasma lances in all directions, ripping it to a cloud of molten debris splattered all over the solar system.

She can use the water to create a giant lens between the earth and the Sun. It wouldn't require using a significant amount of the water on earth either, a relatively thin layer with concentric ripples would do the trick.

# Salinity

An alternative, focusing on the title of the goddess: She's not a not just goddess of water, she's a goddess of the sea. So in addition to powers concerning water, she should have powers concerning salt.

Making formerly fresh water brackish and undrinkable should be in her wheelhouse(there is frequent mythological precedent for rivers and streams and the like). Massively increase the salinity of all the water on the planet, including that inside living cells, which will cause them to rupture due to osmosis, destroying all living things.

Has a "thematic benefit" that she's not removing water from the planet, nor chasing its form, and is keeping with being a "sea goddess" rather than a "water goddess".

All that is needed is to increase water density enough to cause formation of a black hole

### Knead Earth's Crust Like Dough

There's enough water on earth to form two giant hands and mash and mix up the rest of the earth into a nice glowing ball of magma/lava (when there's no longer a crust is there a difference?) Sure the edges of the hands would be constantly exploding/evaporating as they pushed on the magma, but there's enough water that she should be able to thoroughly mix the current crust in before the hands all turn to steam.