Could a Dwarven Civilization Exist?

Question

Could a Dwarven society as described by Tolkien mythology actually work? Dwarves for the purposes of this question are short, stout, bearded men and women who live primarily underground. They have a medieval level of technology although perhaps some advanced metallurgy techniques. They mine deep into mountains, creating vast networks of chambers and halls where they dwell.

There seem to me to be several unaddressed problems with how a Dwarven society would work.

Mining: We have a hard time digging into the earth safely even with modern technology. Could Dwarves actually create safe underground dwellings at a medieval tech level and without the use of magic? How deeply could such a society safely dig without the risk of poisonous gasses, cave-ins, or Balrogs doing them in? Are the massive subterranean structures we see in Middle-Earth possible?

Air. Mammals exhale carbon dioxide that will inhibit their ability to get oxygen into their blood if it reaches too high a level. As a tunnel goes deeper into the Earth and further from the surface air supply the Dwarves will eventually suffocate. How can they cope with this and keep massive underground networks such as the Mines of Moria habitable? Today we use fans to generate circulating air networks. Is there any way for the Dwarves to replicate such tools with medieval technology?

Food. Let us say for the purposes of this question that Dwarves do not farm or hunt above ground. What could they eat? Are there any ways to grow food underground? They need a renewable, reliable food supply for a large population. Trade would be one option, but would require the Dwarves to live in close proximity to surface dwellers and would make the Dwarves wholly dependent on their trade partners.

None of the answers need refer to Middle-Earth in particular. I only mention it because it’s something that most people are familiar with and has inspired most of the Dwarves we see in modern fantasy. I’m interested in non-magical, non-fantasy answers. I essentially want to know if a hairy, burly group of men and women could live underground on earth.

No other problems come to mind, but I’m sure there are others. If anyone else has concerns about the feasibility of a Tolkien Dwarven society please bring them up as well.

Answer 1

Some things need to be addressed here. Can the structures be made? When does a mine get too hot? What about asphyxiation? What about food? It should be noted that many of the issues here can be solved or compounded by local factors, so this answer applies in general cases, not specifics. Where the dwarves decide to mine, what rock they are mining, and other factors can make a place viable or not.

The Structures

Obviously, these dwarves are masters of rock-cut architecture. There are examples, mostly in India, of cities, towns, and temples which were carved from stone. It is very possible, as we humans did it! However, I doubt much of these go as deep as someone may think the Mines of Moria go.

In any case, the structures themselves can happen with Middle Age tools and techniques. The limiting factors are likely how hot it got and asphyxiation in your dwarf-town. In fact, it may be easier to make Gothic Architecture inside of mountains because you start at the ceiling and dig down!

Underground Temperatures

The TauTona and Mponeng Mines are really deep; about 3.5 km and 4 km below the surface, respectively. They report temperatures of 55-60 degrees C and 66 degrees C. Way too hot for most human-like biologies to function. Many sources claim that the geothermal gradient is about 25 degrees C per km, so unless your dwarves have some awesome ability to cool themselves, you would not be going that deep. Humans can live at about 21 C quite comfortably, but ~38 C can cause problems. At that temperature, you run a huge risk of heat exhaustion and heat stroke, as the rock and air around you is as warm as you are.

To put this in perspective, 1 km may actually be deeper than you realize, as it isn't a long distance to walk, but it is a long distance to dig or fall. (The Grand Canyon can get up to 1.8 km deep!) Then again, if the surface is freezing, then getting 25 C warmer would be really nice.

Air

This is a tricky one. Living on a mountain, you could use winds to make bellows and pipes to move air as needed down pipes or tunnels. Bellows are so old we are not sure who made them. There are even words for them in Old Norse! They were around in the Middle Ages of Europe. This is very energy-intensive, though, so it is not the best solution.

What about the open spaces and halls you seen in the movies?

This may actually help, because the large body of air (with internal convection) can give a dwarf population enough air to last them longer than if it was a narrow hall. You would just need some well-placed windows up high or on opposite sides of your mountain to allow fresh air in. Additionally, we know of many caves that are really big!

If these dwarves were especially good with fluid dynamics, they could create an air tunnel system which takes prevailing winds and temperature gradients to funnel fresh air through their tunnels. This is tricky, and can be difficult to do.

You also need to worry about damps. Those are pockets of dangerous air. The technology used to manage them range from very complicated to hanging sheets to guide air. Obviously, dwarves can hang sheets; they just need to guide the air to a place where it can safely diffuse. Once again, the giant halls and open spaces would be helpful.

Food

Cave Ecosystems are difficult. Here is a list of troglobites; creatures who exclusively live in caves. There is not much there that is very nutritious, nor is it especially abundant. The US National Park Service claims that caves mostly rely on resources coming in from the outside. That is prime real estate for decomposers, like mushrooms and insects!

You can have an ecosystem which does not rely on sunlight at all, as the oceanic thermal vents have shown us. Similarly, you can have chemoautotrophic bacteria which could, in theory, form the foundation of a dwarf-sustaining ecosystem. The downside, however, is that cave-life seems to not get especially large. If you look at the list of troglobites, you will see a lack of mammals.

There are people who want to grow plants underground, such as the people of growing underground. However, you would need a source a light, and LEDs / full spectrum lighting is likely beyond our dwarves. You could try a series of mirrors, but mirrors of that size and quality would likely be too hard for dwarves to make. (They may have been able to use tin or other metals, but its unlikely.)

Given these lists of troglobites, and whatever finds its way into caves, it would be safe to assume that dwarves have no scruples about eating fungi, fish, or insects. Those living strictly underground would rely on eating those.

Answer 2

Mining

There are a number of species on earth, including insects, mammals, birds, and reptiles that create massive structures underground, so it's not inconceivable that such burrowing could be done with medieval technology. In fact, we were able to create fairly incredible mines in medieval times.

Perhaps early dwarves were burrowing humans, and they subsequently got better and better about reinforcing their structures with wood and then stone. Since they were "naturally" burrowers, they had deep knowledge about different types of the land, and the earth and stone underneath it. This let them select ideal locations for mines and burrows.

Poisonous gases, cave ins, etc. would be real problems, and conceivably, thousands (if not millions) of dwarfs would have died because of this. However, over time, they got better and better about building massive structures underground. Imagine, for instance, if the structural technology of the pyramids were leveraged to support massive underground chambers. By the "Roman Era", dwarves would have significantly improved on this technology.

Air

Ants are capable of building incredible underground chambers that properly circulate and ventilate air. Dwarves could also develop this technology. It would rely on judicious use of air pressure differences and/or wind to help vent carbon dioxide.

Also, dwarves may also evolve to be more tolerant of CO₂ or other gasses, which would allow them to remain in poorly ventilated mines longer.

More than just air, however, water and flooding would be a big problem. However, technology for moving and pumping water was well established by medieval times, so this would not likely pose too big a problem for our dwarves.

Food

Dwarves would likely be dependent on above-ground food. However, there are a couple possibilities.

One option would be to raise animals underground, and to feed them with plants like grasses or lichen that could grow in the meager light provided by torches (or perhaps skylights). This would require large areas to raise these animals and enough greenery to feed them.

A slightly more ridiculous option would be to cultivate certain kinds of root vegetable that would grow deep into the earth. Then, the dwarves could simply cut off the roots (or pick the potatoes, peanuts, etc.) from underneath, and the plant would then regrow those. It would likely require at least a few dwarves to properly protect and maintain the crops above ground, but would eliminate the need to transport the foodstuffs from the surface.

Answer 3

Mining

Such vast underground structures occur naturally and as others have noted in areas of suitable rock people actually have built and used large underground complexes. The real question is why the Dwarves would stay underground instead of living above ground in areas of harder rock. It would help if we assumed some magic that gives benefits either to or from living underground.

Air

A properly planned cave system would have a natural circulation. It would be reasonable to presume the Dwarves can create such structures. This is because to people living underground the differences in circulation and air quality would be something they'd be constantly aware of. They'd not only be sensitive to bad air quality, they'd easily notice what changes would make a positive (or negative) difference, and they would talk about it and pass what they learned to the next generation. In fact, I think the Dwarves would rely on the air currents and quality for navigating their cave complexes. And be able to scent minerals? That might explain being exclusively miners. And not being bothered by the dark.

In practical terms, they'd use natural convection in warmer parts to draw air from outside through the caves. The "warmer parts" would include deep parts with higher temperature, any forges or cooking fires the dwarves would have, and small outside towers on southern faces of mountains where sun would heat the rock and create an air current drawing air out. Intake would be through large shadowed caves.

You would still want some biological adaptation to operating with lower oxygen. Not only would that help with dealing low oxygen areas, it would have other benefits. Your homes would be very uncomfortable for surface dwellers to invade, even before you close few shutters to cut off air circulation in the attacked area. In underground fighting people with lower oxygen needs would have a real edge. Lower oxygen levels would also reduce the risk of gas explosions and if you could also hold your breath longer it might help with toxic gasses as well.

Food

It is generally presumed the Dwarves get most of their food from above ground either from secluded mountain terraces accessible only from air or underground or in trade with surface dwellers. Even Dwarves need some excuse to forge new objects, so trading the old for food would be natural. And food is fairly cheap in comparison to gold and gems. So the dwarves would probably rely on surface food and lots of storage. Mountain gardens would be rather fertile due to large amount of compost available. And you really want some place to put that compost...

Some food could be harvested from underground streams that came in from the surface. In addition to fish and other directly edible things almost anything organic could be used for mushroom farming. Bats could be domesticated. Same with other species that hunt on the surface but live in the caves.

Caves have much more stable temperature than the surface. The dwarves might be adapted to this and thus waste less energy controlling their body temperature. They might also have lower metabolism in general. This would reduce the need for food and increase life span.

The ultimate solution would be a food source that relies on chemosynthesis. The Dwarves themselves might be able use low concentration methane in the air for energy. This would not only make living underground more practical, it might explain why they live underground in the first place. Another suitable gas is carbon monoxide, which you can easily create from coal. Since both these gasses are quite dangerous having a natural ability to consume them would not only free you from surface food, it would make living underground much safer. And if you could breathe air with carbon monoxide in it and had ready systems for creating carbon monoxide already in operation, invasions by surface dwellers would be a non-issue.

Answer 4

As far as food goes, is it significantly harder for dwarves living underground to obtain food from the surface than it is for an urbanite to obtain it from the surrounding countryside? Is it harder to provision Moria than Minas Tirith, for instance?

This is very nicely expressed by Terry Pratchett in Night Watch:

In a few hours the shops out there were expecting deliveries, and they weren't going to arrive. ... Every day, maybe a hundred cows died for Ankh-Morpork. So did a flock of sheep and a herd of pigs and the gods alone knew how many ducks, chickens and geese. Flour? He’d heard it was eighty tons, and about the same amount of potatoes and maybe twenty tons of herring. ... Every day, forty thousand eggs were laid for the city. Every day, hundreds, thousands of carts and boats and barges converged on the city with fish and honey and oysters and olives and eels and lobsters. And then think of the horses dragging this stuff, and the windmills ... and the wool coming in, too, every day, the cloth, the tobacco, the spices, the ore, the timber, the cheese, the coal, the fat, the tallow, the hay every damn day. ... Against the dark screen of night, Vimes had a vision of Ankh-Morpork. It wasn’t a city, it was a process, a weight on the world that distorted the land for hundreds of miles around. People who’d never see it in their whole life nevertheless spent their life working for it. Thousands and thousands of green acres were part of it, forests were part of it. It drew in and consumed ...

... and gave back the dung from its pens and the soot from its chimneys, and steel, and saucepans, and all the tools by which its food was made. And also clothes, and fashions and ideas and interesting vices, songs and knowledge and something which, if looked at in the right light, was called civilization. That’s what civilization meant. It meant the city.

Answer 5

See for example:

Wikipedia and Goreme sites.

I recall being told on a visit to one of the Cappadocian sites Kaymaklı and Derinkuyu underground cities that it was originally 10 stories deep.

A vertical ventilation shaft somehow ensured air circulation. Building within a mountain chain rather than down into a volcanic plain might provide a big improvement on the possible depth than can be ventilated. This is called the Venturi effect: the vertical shaft extends into areas with higher air flow at lower pressure, causing a vacuum at bottom of shaft. However, a mountain chain would also have much harder rock than Cappadocia with consequent effect on mining, to the extent of being on the face of it quite impractical.

To be quite honest, when I visited there I was reminded more of the Goblin Caves in the Hobbit than the Mines of Moria.

[With regard to the engineering possibility, you could argue that Peter Jackson's Moria was more ambitious than necessarily implied by the Tolkien text.]

Note that these cave dwellers had their agriculture on the surface. I do not recall anything indicating that the dwarves produced food underground. Certainly they are supposed to have traded manufactures for food. I haven't looked up the detailed timeline, but Moria was supposed to be at its height when there was a thriving economy in Eregion.

So, in summary, the air and food could probably be solved non-magically, but the mining of mountain rock less so.

Answer 6

Farming underground

You can grow mushrooms underground pretty easily. But you have to bring the substrate (dung, soil, tree bark) they grown on from the surface. As you have constant temperature year round underground, this will be great to have food for the winter. You might even be able to feed some rodents with it to put some fresh meat on the table.

Fishing underground

If there's a river with an underground part, you might be able to catch some fish that are passing through or cave fish living off what is brought by the water from the sunny part of the river. Some Olms and Salamanders also live in caves with water. But there always has to be water coming in from the outside bringing the nutrients.

You might be able to build a canal that diverts a regular river into your underground mine. Then you can leisurely eat anything it brings with it. Fish farms would be possible too, but you need to bring the fish food from somewhere else.

Answer 7

Creating a chimney effect in a mine under a mountain would provide adequate ventilation, and the medieval world (dwarf world equivalent) knew windmills. With modern power and light would be much easier, and mining technology now means we can let the machine do it, and with renewable energy. A bit surprising that there are not more fantasy underground cities in the mountains, now. May be a gap in the market. See fantasy underground city in the Blue Mountains (west of Sydney Australia) meetup group.

Answer 8

I worked on this problem a bit. Understand this was in a mythos in which pools of lava would be safe to stand reasonably near for a short time, so a few resources are available that should not be.

There is this thing in the ocean called a tube worm that harbors bacteria that live off the heat exchanges between deep thermal vents and the ocean. Here we have not such a good cold sink but a really good heat source, so it's going to be hotter. I posited the same kind of thing could live here. Its biologic processes would drive soil breakdown and nutrient release leading to (ultimately) lava-drive mushroom growth. Of course recycling waste is a must. Guess what mushrooms like anyway. To deal with the contamination I further posited that dwarves brewed all the mushrooms into beer.

Absurd? Well, no more than whatever allows standing pools of lava in caves to be safe to approach.

Oh, and when they go to industrialize, guess where the power will be coming from?

Answer 9

I'm not an expert on these things but here are some thoughts I have gathered together:

Mining: Dwarfs are known to be very skilled at mining and mining technology. On the other hand dwarfs are also know to be very self-centered and not exactly the friendliest folks towards others (as seen in all of Tolkien's works). This begs the question - how good are dwarfs at mining really? Because dwarfs are so fond of digging precious stones and metals from the earth I would guess that they would also fiercely guard their mining techniques and technologies so that no one else does it thus creating a monopoly over the trade with such items in Middle Earth. In Lord of The Rings we saw that Saruman was able to produce an explosive substance, which was later used to blow up part of the wall of Helm's Deep, but who says that he didn't steal this from someone else (the dwarfs for example?) using his palantir (the stone which allows you to see far, far from where you are including breaking the boundaries of space and time).

Note: See the end of the post

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Air: There are of course limitations as to how deep one can dig however in terms of mining and air quality there are ways to provide fresh air at a certain depth using extensive ventilation system by creating drafts which 1)take oxygen from above the ground and 2)remove carbon dioxide from underground. That said air quality does degrade the deeper you go however you also have to consider the ability to adapt to certain conditions. Take the people who live up high in the Himalayas. The higher you go the less oxygen there is in the air. However people there have lived in such conditions for hundreds (or more) of years which lead to their anatomy adapting to the extreme conditions. Of course high levels of carbon dioxide are deadly but since dwarfs live in such condition my guess would be that their anatomy is adapted to produce less carbon dioxide and consume less oxygen plus better ability to get oxygen from air with less oxygen. This would allow dwarfs to survive at a much deeper level compared to other human-like creatures. Last but not least the size of all the shafts and halls do provide bigger pockets of air thus allowing better distribution of carbon dioxide.

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Food: While dwarfs are known for their mining and metallurgic skills in terms of farming and breeding stock they lack a lot. However just like in real life one can use trade to export metals, jewelery, precious stones etc. and import food and beverage instead (similar to what Japan does in terms of importing minerals, metals and fuel due to the very limited resources it has). In addition to that there are a lot of mushrooms and other plants that grow in complete darkness and also with enough artificial light, soil and water one can also create somewhat efficient farms underground. Plants also like having carbon dioxide around them (in modern terms I believe this is the so called carbon farming where carbon dioxide is additionally added to the air which the plants breath to accelerate their growth and efficiency) which would partially take care of the excessive build up of carbon dioxide underground. On the other hand plants also produce carbon dioxide on their own which will add to the already rich on carbon dioxide environment. It's a tricky situation with this one. Also I don't recall ever reading or seeing underground farms in any of Tolkien's works so my guess would be using trade as the only way of providing food and drinks to a dwarf society. Animals, who normally live above ground level, can also be moved underground though due to the lack of natural light such animals would be more fragile, probably blind (or at least with a far inferior vision capabilities compared to their representatives who live a normal live under the sun and in open spaces) and also this would be yet another source of carbon dioxide.

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If we go away from Tolkien's universe there are many universes where dwarfs are even more advanced especially in the usage of explosives and steam (in addition to possible alliances with the gnomes) which tends to go towards a more steampunkish theme. This allows creating more advanced machinery which will allows digging deeper, creating a more suitable habitat for a dwarven society etc. etc.

Answer 10

I have an idea: what if you made some sort of plant-like organism that evolved specifically to absorb thermal energy from underground thermal vents? This would be a good way to solve the whole “getting food underground” problem. They could even use some of those “thermal plants” to feed livestock.

Answer 11

True underground dwarves would need a source of energy to replace sunlight, and a way to convert it into food. A silicon based life-form like a troll might be able to eat coal directly, but dwarves are mammals. Even trolls would eat their way through a coal deposit in a few generations.

I think this would be impossible with the usual iron-age fantasy technology. They could burn coal to power electric lights, and use that to farm but like the trolls, they'd run out before long because they'd would need to use it far faster than we do.

Geothermal energy won't run out for billions of years, so they could use that to power the lights for their farm. Or a rich uranium deposit forming a natural nuclear fission reactor. They'd have to develop good drills, pumps, turbines, generators and electric lights, but being tied to underground power would explain why they've not used their relatively advanced technology to out-compete the surface dwellers.

If you can solve the food problem, everything else is easy in comparison.