# How could magic slowly be destroying the world? [closed]

Hypothesis: A world with magic users is (unbeknownst to them) slowly dying because of magic usage

Question: What would be the underlying cause of this slow decay?

Conditions:

• The magic in this world is in some way respecting the law of conservation of energy. If energy is spent while using magic (performing telekinesis, pyrokinesis, you name it) it is taken from elsewhere (from within, the environment, certain objects, etc.)
• The magic users are oblivious to this fact which means that the 'slow decay' of the world should not be easily determined

The question is in some ways inspired by the old Dark Sun campaigns, where you had 'defiling' and 'preserving' magic. Defiling magic caused a slow decay of the world (in the sense that energy was taken from plants and life in general) and finally led to a Mad Max-like desert world that could barely sustain life. Obviously this is quite visible and its progression was clear to the world's inhabitants.

A different dynamic would be that magic users are merrily shooting their fireballs or constructing their earth golems, until they are confronted with thier plausible demise. Liken it to the effect fossile fuels have had on our world: fossile fuels certainly made our lives easier and allowed many scientific advancements, but at some point we figured out we can no longer continue like this for it might lead to catastrophic results for our 'habitat'. But in the interim we weren't aware of its harm.

Ideas I've had were drawing energy from the sun. However, it was justly pointed out that the sun cannot reasonably be depleted if you want the magic spent to have the same energy output as the energy input. It could also be sourced from the core of the planet, which might destabilize the planet's magnetic field and kill all the inhabitants due to the sun's radiation. Not sure if this theory could hold as I'm quite clearly not a scientist.

• Given that it's your magic system and any decisions about it are entirely up to you, this can be answered however you want. We're not a brainstorming site. We're not here to generate ideas for you. Jan 17 at 15:39
• As long as the question is "good subjective", it's fine. The Stack Overflow blog had a great writeup about this: stackoverflow.blog/2010/09/29/good-subjective-bad-subjective Stack Exchange even created a new Exchange site specifically for more subjective programming questions. This question is fine and focused within concepts of "World Building" and seems to meet the definition of "Good Subjective". Voted to leave open. Jan 17 at 16:23
• Hello GilouLeFou, welcome to Worldbuilding. For future reference, please understand that questions that lead to all answers having the same value are prohibited. This is such a question. You've given us no guidance as to your goals or how you will choose a best answer. This is what @sphennings was talking about and why JamieB is incorrect. We're lenient with new users, but all questions are expected to solve a specific problem with the expectation of a best answer. You can learn more by carefully reading the tour, help center and help center. Thanks.
– JBH
Jan 17 at 16:37
• @JamieB that a question gets answers doesn't mean that the question is good. Many users forget the "answer only well asked questions" rule. Some in good faith, some simply because they don't care.
– L.Dutch
Jan 18 at 4:29
• "Obviously this is quite visible and its progression was clear to the world's inhabitants" - if it doesn't happen from one day to the next, but takes many decades or even centuries, then the slow changes won't be clear for everyone, and even for those who notice might think it will be the issue of later generations, and some might deny it outright.
– vsz
Jan 18 at 5:31

A magic based world has magic based life.

Life draws from available resources. Life on earth evolved from materials available on earth. There's always a question of what alien life might be like, if they had to evolve in different circumstances with different resources available -- different "building blocks". In a world of magic, it's reasonable to assume that life has evolved with "magic" as a building block.

There may be basic cellular processes on this planet that have evolved to rely on magic. Weak magic is to them as weak oxygen is to us or weak sunlight is to Earth plants. No magic? Cells die. The exact biological process probably isn't important (and may well be beyond the science of your world to comprehend anyway) but the basic idea is that life in a world of magic evolved to rely on magic.

Spellcasters expending magic is therefore something like a nuclear winter. Except instead of kicking up dust to block sunlight, it's either interfering in the magical field used by all life, or it's depleting it faster than it's renewed. Life evolved to require magic, and now it's getting something like "magical suffocation" -- it's not able to get enough of it, and this causes failures on the cellular level.

You could even take it a step further. A magical universe could have magical physics. Instead of the four fundamental forces of physics, they have five. Or more. The extra ones require magic. Weakened magic could cause failure at the molecular level. You could get as fantastical and far removed from science as you want, here, but the key point is that if a world evolved in magic, then magic is probably a building block of life and without it, life -- and possibly the world itself -- suffers just the same as we might suffer if there was a lack of CO2, sunlight, or the strong nuclear force. Whatever the wellspring of magic is, it is becoming clear that overuse is stretching it thin.

• +1. Tangentially related: "What Good Is A Glass Dagger?", by Larry Niven, in which a character whose life depends on magic navigates a world in which magic is slowly disappearing.
– Qami
Jan 18 at 12:16

Each time magic is used, the gate opens a little wider.

The wind gibbers with Their voices, and the earth mutters with Their consciousness. They bend the forest and crush the city, yet may not forest or city behold the hand that smites. Kadath in the cold waste hath known Them, and what man knows Kadath? The ice desert of the South and the sunken isles of Ocean hold stones whereon Their seal is engraven, but who hath seen the deep frozen city or the sealed tower long garlanded with seaweed and barnacles? Great Cthulhu is Their cousin, yet can he spy Them only dimly. Iä! Shub-Niggurath! As a foulness shall ye know Them. Their hand is at your throats, yet ye see Them not; and Their habitation is even one with your guarded threshold. Yog-Sothoth is the key to the gate, whereby the spheres meet. Man rules now where They ruled once; They shall soon rule where man rules now. After summer is winter, and after winter summer. They wait patient and potent, for here shall They reign again.

The Dunwich Horror, HP Lovecraft.

Your magic users are oblivious, most of them. They don't know about the Old Ones, and the fact that they are waiting, inching closer, ready to clean off the world and take it back. The gate between the worlds has been shut for a long time. The magic users don't know that every use of magic opens that gate a little wider. Little things from that plane slip through. Horrible little things, that corrupt and change the earth. And so as the Old Ones get closer the world too feels the foulness. When the first one comes through the gate it will open it for the rest. That will be the end.

• Oo, I like it. This is old fairy tale lore too -- the "veil", the thinness thereof, and what's on the other side. See also: Stranger Things. I recall Pratchett enjoyed playing with the idea in his Discworld series too. Less about magic killing our world, per se, and more about it weakening the barriers that keeps out the things that want to kill our world... Jan 17 at 21:04
• @JamieB Lovecraft has a lot of issues, but a fair bit of what he wrote was drawn from earlier sources, either actual folklore, or other writers' own takes. I'd say though that the CoC approach tends to rely on magic being a fairly new/rediscovered tool, and may not fit OP's intent. Jan 18 at 6:45
• @Willk It's not at all what I had in mind at first (I was thinking more 'scientifically'), but I really like your idea for my worldbuilding! Jan 18 at 8:29

## Magic's Forgotten Origins

Any sufficiently advanced technology is indistinguishable from magic.

Your inhabitants have been living in a techno paradise for so long, they don't even know how the magic works: Trillions and trillions of nanobots spread over the entire world, governed by their distributed intelligence and human voice commands, have been doing your inhabitants bidding. The nanobots spread themselves to every corner of the world through wind and water. It's not a spell, it's a voice command.

To avoid a grey goo scenario, the nanobots cannot replicate without very explicit instructions. This knowledge is lost, and every spell inevitably consumes some of the nanobots through wear and tear, or self destructive actions such as fire spells, which force the nanobots to combust.

As the number of nanobots dwindle, magic becomes weaker and weaker, the intelligence of the network diminishes, and less and less complex "spells" (requests) can be understood/fulfilled.

Maybe one of your characters will get lucky and find a very interesting book describing how magic works, and become a more powerful wizard than anyone thought possible. They could kill at arbitrary distances, take away others abilities, create structures or items, create entirely new spells, manifest a copy of their body in other locations, and maybe even replenish the "magical energy", for everyone, or a select few. Anyone with this knowledge could become a god.

There could be regions, like space, where magic doesn't work, or works weakly based on the current nanobot population.

Any sufficiently studied magic is indistinguishable from science.

• This explains why the magic might fade over time, but not why it would kill the world, #Imjustsaying. Jan 18 at 10:19
• @user98816 The plant life on the planet they live on is dependent on nanobots since it actually was terraformed - think mars like. The upkeep isn't much - usually the nanobots only need to plant seeds and give them some soil to get them started. This dependence is compounded by the plants being artificially selected for traits such as beauty, and how much fruit they bear over things like hardiness. Jan 18 at 20:11
• I would go as far to say that nanobots were designed to be unable to replicate to avoid nightmare replicator style scenarios. Jan 18 at 20:13
• I just had another thought. Due to changing weather and lack of global weather maintenance some areas became arid and have a higher concentration of working nanobots (they've been in hibernation). There are a select few areas where wind has blown these nanobots into large sand dunes such as Great Sand Dunes national park where the dunes have layers upon layers of functional nanobots. Here vast power can be attained but not many know since it's far away from more populous regions due to being arid. Jan 18 at 20:33
• Rivers would carry nanobots similar to sediment, but human populations are usually gathered around rivers. This way cities and towns get a consistent source of nanobots while also consistently using them. However places where not many people live such as Arizona pre AC would see very high concentrations in intermittent riverbeds. Jan 18 at 20:42

# Destruction of the ozone layer

Energy can be taken from many things. It doesn't need to be one thing. This spread out energy can also delay the effect. One part it could take the energy from is the ozone layer, reducing ozone to other forms.

Before global warming we had something much more direct. We used gasses that started to bond with the ozone layer. This prevented the benefit it offers for all life. Reduce the UV waves from the sun that reach the ground. UV isn't noticed directly by humans, as it's an invisible form of 'light'. All consequences can be disastrous, but difficult to detect.

UV can influence on both a long and a short time scale, from an 'everything in the sunlight will die', to 'reduction in crops, sea life and increase in cancer', to just minor inconveniences. You probably want to go for the middle ground, where at first nothing much is happening, but slowly things take effect. This increases to big changes we have difficulty noticing, like many species of (sea) animals and plants reduce in numbers. This in years or decades the eco system can strain to bursting, then tipping over. For humans it might look like less crops for a year or two and less insects, then suddenly you have plagues of certain species and mass deaths of others, making much life quite difficult. This can lead to more magic use to fix problems or stay alive, causing the increase of all effects.

From the setting I suspect knowledge of UV and ozone is absent or little, making even people who notice powerless to change it. The utility of magic might be too high to give up as well for many people, making them deny, ignore or even abuse it. If the gasses that attacked the ozone layer were the key to huge amounts of cheap energy and strong military might, it would still be in use today.

• I like the idea, but to really pull from the real life example, magic producing a by-product that reacts with ozone just like cfcs do would fit better than taking an arbitrary energy. Jan 18 at 9:00

### Accelerated entropy

Magic is about getting things done, and fast.

Want to move earth? Use magic to do millions of "grain moves". Want vegetables? Grow them from thin air very fast. Want to burn an enemy to a crisp? Send "heat" in then faster than they can "refrigerate" themselves.

But there is a thing. You are basically moving entropy around with magic, not creating these effects directly. Every time someone uses magic, some land, somewhere, gets a little more barren, that is, a state of disorder, randomness, or uncertainty. And so the world dies a little.

• This would be my answer, but consider leaning more into the 3 laws of thermodynamics. Since entropy in the universe at large is always increasing, if you create order in one place (whether that is building house or conjuring a fireball), you're creating a bit more disorder elsewhere in exchange. The more ordered (unnatural) the creation, the more disorder (entropy) created. Eventually the universe will just be all entropy: spread out unordered low energy particles, without even the organization required to support life anywhere. Jan 18 at 15:08
• ...but of course magic like everything else has to draw on nearby order, which means when you create artificial order, you increase the entropy around you. If people do this constantly all over the planet, it would be the entire planet's entropy increased. Jan 18 at 15:18
• I was thinking this, because I've actually read some of a series that almost takes the opposite approach (but similar consequences). In that book, the generation of entropy also created the fuel for magic. And so having areas of high entropy was very useful for magic users, but would also ultimately lead to no world at all.
– JMac
Jan 18 at 17:50

# Greenhouse gasses

The key equation for digesting glucose is

$$\text{Glucose } +\text{ Oxygen } \to \text{ Energy } + \text{Carbon Dioxide} + \text{Water}$$

For photosynthesis you have

$$\text{Carbon Dioxide } +\text{ Water } + \text{ Light } \to \text{ Glucose } + \text{Oxygen}$$

For magic you have

$$\text{Mana } +\text{ Oxygen } \to \text{ Effect } + \text{Carbon Dioxide}$$

Where "Effect" is the fireball, scrying, power to fly, talking with animals, and so forth.

Powerful spells gobble up oxygen from the atmosphere and expel greenhouse gasses. Too much magic and the ice caps melt and sea levels rise and yada yada yada.

• Trying not to nitpick but the chemist in me won’t let this go. My understanding of “mana” is that it’s a supernatural form of energy. But for greenhouse gases to be released, carbon must be consumed. Can mana be carbon-based? Jan 18 at 3:03
• @TheresaKay Maybe mana is just an energy-storing chemical, like glucose? That'd explain the existence of mana potions... Jan 18 at 8:31
• @TheresaKay That's what makes it magic ;-) Jan 18 at 12:53
• "Mana" is not a general package of energy. It's a bible word, like "mana from heaven" which was food dropped from heaven and prevented Moses and his people from dying of hunger in the desert (Cambridge dictionary). Any edible substance will contain carbon, so I agree with the formula put by Daron. Magic in the case of "mana" just obfuscates effects that would take place anyway, producing CO2. Jan 18 at 14:34
• @Goodies "Mana" can be whatever the writer wants it to be. Jan 18 at 14:35

## Nuclear Magic

Mages cast spells by manipulating the structure of atoms. This is done with the mages' fundamental ability to alter probability and thus they can bias the quantum mechanics underlying all matter. Because the low-level effects of spells are probabilistic, the spells just do mostly what they are supposed to do. A spell based on a chemical reaction does mostly mess with the Valence electrons. But part of the magic of such a spell interferes with other parts of the atom, leading to nuclear reactions. Those result in an array of catastrophic effects destroying the world.

Gamma Radiation Very high-frequency light. The photons damage organic molecules and cause mutation and radiation sickness.

Neutron Radiation What precisely free neurons do depends on their velocity. The fast ones "just" punch complex molecules apart. The slow ones are more hazardous. They are absorbed by surrounding matter leading to a phenomenon called neutron activation. This transmutes elements into unstable isotopes, leading to further decay in the environment.

Nuclear Explosions Mages can set off nukes. This might sound like it would break any setting, but you can limit the damage this does. Have nuclear magic be considered dark, forbidden, and forgotten. Most mages only do this as a side effect. Secondly, no enchantment or artifice; magic needs an active caster whose spells have a ramp-up time. This means that an explosion will get the caster itself before it gets out of hand. I know that this isn't exactly how nukes work, but those mages wouldn't be working with fissables directly. Iron is the element where you can't extract any energy with nuclear reactions. Heavier elements are affected by fission, and lighter ones are affected by fusion. Those reactions are not that energy efficient for the most part. So the mages are not playing with nukes unless they figure out nuclear physics.

Nuclear or Weird Apocalypse This world has world-ending lore. A mage who figures out uranium enrichment, how to get their hands on any fusion fuel with a low Lawson Criterion, how to make antimatter in large quantities, or how to produce any number of exotic particles with their dark nuclear magic is insanely dangerous. Depending on what they figure out, this could kill anything from a city to the local part of the universe.

## The aliens are unhappy

Magic often seems to have an innate intelligence - cast your spell and something happens that seems to understand your wishes.

Actually, that's because it's being run by a group of advanced aliens who have been running the planet as a kind of zoo / experiment / entertainment. They introduced the idea of magic to humour themselves, and/or assist the inhabitants with their daily needs. But they're getting a bit fed up. Too much greed is making things difficult. So they're losing interest, and getting a bit sloppy with their actions, ignoring the "spells" or just doing something different out of spite. And now there's a growing movement who want to abandon the experiment, clean out the spellcasting race, or just plain send it hurtling into the sun.

Your humble hero is the only one to understand this. But nobody else believes them, and they can't change the situation alone...

Pollution

"pollution" in a more generic sense is where I would go.

Food goes into your body > it gets processed > out comes waste... Of various types. Sweat. Pee. Poop. Eye gunk. Boogers.

Raw materials gets processed into goods. Those goods get used. Resulting stuff gets dumped into garbage piles, into the ocean, into our water sources, etc. Natural disasters destroy and unleash waste while we also create ever larger trash piles.

As you "injest" magic? It gets processed into effects. "(performing telekinesis, pyrokinesis, you name it)". Well after that? Where is that "energy"? The residue? the processed magic?

We have the same problem with our oceans. Slowly but surely, we pull stuff from the ground. process it. and then a very large portion of waste makes it into the ocean while we also over-fish and over-develop.

so as "pure" magic gets processed and refined and used? Out the other end it gets output and then it's back in the atmosphere. Some of it gets recycled - like water becomes clouds becomes new streams... but some of it is left over "waste". It gets put into the system as "forever chemicals" that eventually build up over time and taint the "well". Too much bad stuff and our water sources are now tainted and you drink it. Then you get cancer or suffer effects from the "bad" water.

As the magic gets used, waste gets created and fed back into the system until some point where the magic is simply covered in "filth". Spells don't do what you want or have unintended side effects - on you and on the animals around you. Requiring more and more purification rituals to get useful mana - and to stop you from going insane from the pollutions in your body or disastrously bad side effects .

Consider all of the resources you have in life. Not just the energy you derive from the things you eat, but the things that you use up, the people that you know, and the broad range of things available for you to do on any day. We don't actually make use of most of those opportunities, but they're out there.

Magic, in a real-world sense, has always been about increasing the probability that good things will come my way. What if that were a limited resource? What if the universe really was a zero-sum game, and that any time I had an opportunity, I was taking that opportunity from someone else? What if a small group of people found a way to harvest the opportunities from future generations to enrich themselves?

This is an abstract concept, but it has a solid application. Find something that isn't a physical resource, and fuel your magic from it. The things I've seen this done for include dreams, color, and gravity, but could even be children's tears or the electro-weak force. Invent an energy economy around that thing, then find a way to exploit it. You then create an opportunity to abuse and exhaust that resource. And then you have a story.

• If a questions isn't a good fit for this site it should not be answered. worldbuilding.stackexchange.com/help/…. Jan 17 at 16:22
• Opinion based is fine, as long as it's focused, part of building a world, and "more than just mindless social fun". I think you can just remove the first sentence which distracts from your answer. Jan 17 at 16:25
• @sphennings, I would agree with that if the concept of "opinion based" weren't so opinion based. Jan 17 at 16:52
• Since you said that you didn't think the question was appropriate. You shouldn't have answered it. Nothing opinion based about that. Jan 17 at 17:59
• Your inability to see the gray area in that statement is symptomatic of why this forum has such issues. The original question was asked in such a way that any specific answer is an opinion. I demonstrated that a non-opinion solution could be provided that generalizes the method of finding an appropriate opinion based solution. I consider this an improvement over the "swat it all down" approach. Jan 17 at 20:02

## Enemy Action or Willful Disregard

Dark Sun itself pretty much gives its own rationale for the decline of its world, multiple ones actually, across the different editions (and novels vs setting books & modules).

So long as there are powerful individuals in your world - mages, rulers, Sorcerer-Kings - with a vested interest in using magic that overrides any concerns around the impact, and/or the ability to direct the worst effects to less-powerful peoples/remote places, you've got your explanation & dramatic conflict in-one.

You can stick with the classic environmental allegory, or go for something more external/exotic (aliens, fae, etc). Dune trod similar ground - with Paul promising to "heal" Arrakis, but ultimately kicking the can down to his son - sins of the fathers and all that.

Malicious intent and an active avoidance of known-facts was implicated in the D&D versions as well as in real-life. Worldbuilding doesn't always need a purely physical-world solution.

Upon reading your question I immediately thought of the world in the light novel "Kumo Desu ga, Nani ka?" (I'm a spider, so what?) Once you find out more about the origin of that world you find out that the humans there found out how to wield the very life force of the world itself. Their reckless use caused the world itself to start dying! This is what created the situation that we are first made aware of at the start of the story; that the world seems to be like a video game (skills, levels, etc). This turned out to be a System created to essentially farm humans; putting in effort to grow strong in the System allowed you to generate energy yourself, and that energy was then harvested when you died and used to slowly heal the planet.