I argue here that preventing a large iceberg from melting is absurdly cheap per unit area compared to just about any other way of making new land, and it's kind of crazy to spend money on space exploration and colonization before colonizing the oceans with floating ice-islands.
This is a very interesting idea.
I'm still unclear if it's actually feasible to build on the ice. Even if most of the mass remains frozen for hundreds of years won't the surface of the ice be constantly melting such that creating building foundations is almost impossible?
you may be able to construct huge stacked layers about 50-100 meters tall made of reinforced pykrete with a whole city or park per layer and very convenient vertical transport between them. These layers will need a very slight amount of active cooling and a sensor network to monitor temperature
Doesn't this prove too much? If pykrete is such a cheap strong material, why don't we use it for regular buildings?
I'm reminded of Project Iceworm. Even massive Greenland icesheets still creep and flow quite a bit on building-relevant timescales.
Yes, creep is a concern but I think it can be kept at bay with geometry and low temperatures. Creep rate is exponential in temperature so keeping ice at -30 degrees or so makes a huge difference. Though I would really need to research this more.
If pykrete is such a cheap strong material, why don't we use it for regular buildings?
Probably because we have the option of tunnelling into regular ground instead for subways. But tunnelling in general is underutilized and overpriced, likely due to lack of innovation, risk aversion, high time preference, property rights problems, NIMBYism etc etc etc. Elon is absolutely right that Tunnels would solve traffic, and tunnelling into rock is better than making a pykrete megastructure.
But you certainly could make a pykrete structure on rock foundations (which are not everywhere!) and have a pretty economically valuable and affordable megastructure in the form of a multilayer city. I tentatively suspect that tunnelling the lower layers and then building skyscrapers (like Manhattan Island) is the superior option though.
In general, megastructures are underbuilt for political economics reasons. Things like The Hoover Dam and the US Highway System would probably be illegal to build today because of NIMBYism. Most of Manhattan Island would be illegal today too.
Also we have aging and shrinking populations in The West so there's immense social pressure to run things as a form of managed decline rather than innovate and build. Old people have lots of capital and limited life left, so they want to make everything quiet and static and peaceful, and they throw their monetary and political capital around to keep things that way.
If pykrete is such a cheap strong material, why don't we use it for regular buildings?
Also, this is sort of obvious, but it's only good for large structures like huge columns. Anything small or intricate will have a lot of surface area and will be hard to keep cool. So this means that it is only useful for a very particular set of applications.
Pykrete is much weaker than concrete. You need to look up actual numbers for both tension and compression, in MPa. Concrete with >50 MPa compressive is common now.
Pykrete is not 50+ times cheaper than concrete. Sawdust is now something like $40/ton + say $20/ton delivery. At 14%, that's $8.40/ton for the sawdust alone. Portland cement is like $130/ton and you only need 15% for concrete, so around $20/ton for the concrete component. Then you need aggregate, but with Pykrete you also need to deal with freezing it, and that's relatively difficult because it has low thermal conductivity.
Concrete with >50 MPa compressive is common
Engineering toolbox lists it as 20-40 MPa
https://www.engineeringtoolbox.com/concrete-properties-d_1223.html
Pure freshwater ice has a compressive strength that varies as |temperature| in Celsius to the power 0.78. So once it gets to say -40 Celsius it has a compressive strength of around 60 MPa
https://ffden-2.phys.uaf.edu/311_fall2004.web.dir/heike_merkel/Slide4.htm
So sufficiently cold pure freshwater ice is in fact stronger than concrete, and I suspect that pykrete is even stronger but I cannot find good data.
Engineering toolbox lists it as 20-40 MPa
...do you think all concrete has the same strength? Here is a paper with "concrete" that has 800 MPa compressive.
So once it gets to say -40 Celsius it has a compressive strength of around 60 MPa
If you care about creep, ice at -20 C shouldn't have >1 MPa on it.
So what is your criterion for caring about creep? How does it vary with temperature? From the limited reading I have done it looks like you basically eliminate creep in practice at -100°C and you can put something like 30MPa on ice.
But I am not clear how sawdust/fiber affects this.
Here is a paper with "concrete" that has 800 MPa compressive.
Sure, but this material is presumably impractical. Practical, cheap concrete seems to be in this 20-40 MPa bracket.
But really, I don't think this idea is particularly limited by the compressive strength of ice. I think the biggest threat is creep of the ice under load, and the difficulty of making an upper layer that covers the ice with good strength and also low thermal conductivity, and is also cheap at huge scale. I think it's doable but it looks like this is the hard part.
I think agricultural waste products like straw can be substituted for sawdust so maybe you are paid to take it off their hands. So you mostly just have to pay for shipping which is between $10 and $20. Then you mix with water so you're down to $1 per cubic yard. Pure Ice is up to 25MPa under compression so maybe you can get to 50MPa with the right Pykrete
with Pykrete you also need to deal with freezing it, and that's relatively difficult because it has low thermal conductivity.
yes, this may be a problem. I think you'd want to deposit it in layers in the cold Antarctic. A 50cm layer per 24 hours might work?
https://www.concretenetwork.com/concrete-prices.html
Concrete is listed here at $170 per cubic yard and UHPC is about 10x that but much of the cost drivers could be eliminated.
A major consideration is how these numbers change when you're talking about making 10 gigatons of the stuff. Water scales well and so does agri waste. I think you might struggle with concrete.
straw can be substituted for sawdust
would need to be finely ground
maybe you are paid to take it off their hands
No, straw / corn stover / etc is not free. Sugarcane bagasse is only worth about its value as fuel, tho.
mostly just have to pay for shipping which is between $10 and $20. Then you mix with water so you're down to $1 per cubic yard
check your math there
Pure Ice is up to 25MPa under compression
Not if you care about creep.
maybe you can get to 50MPa with the right Pykrete
No, fiber reinforcement mostly affects the tensile strength.
Concrete is listed here at $170 per cubic yard
that's poured, not raw material costs
UHPC is about 10x that
No. Maybe for overpriced proprietary mixes with >100 MPa, but we were talking about 50 MPa concrete.
we were talking about 50 MPa concrete
So how expensive is 30-50MPa concrete in terms of pure raw materials at large scale?
For 50 MPa concrete you basically need to add 1% of additives that are maybe $3500/ton.
For much higher strengths you start needing expensive stuff, eg silica fume.
Hmm. But I suspect you could bring the cost of that down since the ingredients are basically just ordinary rock. So maybe there is something to be said for UHPC concrete megastructures if you can scale up and vertically integrate the manufacturing.
something to be said for UHPC concrete megastructures if you can scale up and vertically integrate the manufacturing
it seems some people agreed with you about that https://www.youtube.com/watch?v=tIQrGfV9oA8
But that's a very expensive building! $5000 per square meter of floor area. And it's not very efficient because lots of its volume is taken up with elevators.
Maybe we should take a step back and consider what your higher-level goals are here. I'm not sure what they are. The possibilities that come to mind are:
What exactly is the difference that's needed from current large cruise ships? Is it size per se? Independent production of food and fuel? Production of trade goods?
It's physical size, permanence (lasts for 200+ years with extensions possible) and cost per unit area (cheap enough for middle class people), safety, no sea motion, pleasant land to live on, strong foundations for large buildings, robustness (not sensitive to one small mistake)
You don't need to produce food, you don't even need to produce physical goods. But you do need a population of 1 million people who are there permanently and call it home.
Does this vary on market at large scale as it does for medium scale? USA vs Asia, for example was 2-3x difference in price in concrete 10 years ago.
In general, things with a higher value per mass have less price variation across countries, because transport costs are less important, but less competition and price transparency, because they're more specialized and lower-volume.
No, fiber reinforcement mostly affects the tensile strength.
I'm a bit confused about this but that is plausible. I have seen some sources giving quite low strength values for ice such as 3MPa but then the same source will report double that value for pykrete. This is probably because of the temperature, purity, grain size etc dependence.
Still, 25 MPa is pretty good and implies a self-support height of 2.6km. Since concrete has 2.4 times the density of pykrete this means you can make taller pykrete structures under pure compression.
Also regarding creep rate I am still somewhat confused. Firstly, there is a claim that fibers drastically reduce creep. Secondly this diagram seems to indicate that to avoid almost all the creep in pure ice you have to cool it to just below -100 degrees Celsius.
Now this is bad news for pure ice but still cooling to -100 degrees Celsius is doable, you just have a 10x greater insulation requirement and you need to run a massive cooling plant. But what about Pykrete under load? I cannot find the data.
Well, yes, but on a per cubic kilometer basis it's probably not that bad. Still, I wonder what can be achieved with smaller amounts of fiber and less extreme temperatures. I am particularly thinking of the initial thick layer of ice that you want to put on top of an iceberg. You don't want that to creep.
check your math there
If you pay $10 per ton for rice husk or rice straw and you dilute it 90% with water, you're left with a cost of $1.
14% may be too much for this. You may get most of the relevant benefits at 5%.
Most importantly, you can't get stuff collected for free, or shipped for $10.
Well, shipping and collection may scale better for large projects. Shipping via ocean is $10/ton for 4000 miles but it may be possible to knock that down in a large operation.
Rice husk and/or straw may be perfect after some processing/shredding.
Also there might be other ingredients that are beneficial on a cost/utility basis, such as basalt fibers, shredded plastic waste, etc.
I think there's some underlying misunderstanding of material science here. You have some fibers, OK, and they have some amount of net strength. Distributing them in ice or whatever at a really low concentration doesn't increase the total amount of strength those fibers have. It's not better than putting those fibers together with less filler, unless:
Adding sawdust to ice, you're not going to get more additional strength per wood than just using good lumber or plywood.
Yes I get that the increase in tensile strength is probably going to be proportional to the percentage of fiber added, but there's no need to go to 14% just because that was the original pykrete formula. Maybe you only need 1/3 of the strength. Or maybe limiting creep is more important. Or maybe you just want to make it less brittle.
I just haven't got the data for the properties of pykrete at lower temperatures and I don't understand how it affects creep rates.
Since the water is almost free you might be able to choose between X meter thick pykrete or 3X meter thick 1/3-strength material.
I also don't fully understand understand what properties you're actually going to need.
I'm still unclear if it's actually feasible to build on the ice. Even if most of the mass remains frozen for hundreds of years won't the surface of the ice be constantly melting
This is addressed in the original post, please search for "Finally you want to finish your top surface(s) with something that doesn’t melt but that is also a good thermal insulator."
Lightweight aggregates like expanded/foamed glass will form that layer, though likely with a honeycomb of basalt fiber-reinforced concrete and a final reinforced concrete topping layer.
Ok thanks. So will the top layer of concrete on foamed glass be floating of a layer of melted ice? Won't it gradually sink as more ice melts into denser water?
It's unclear to me how thick this layer is supposed to be. Will building foundations go though it and be anchored in the pykrete below? Presumably it's not possible to build building foundations in foamed glass?
will the top layer of concrete on foamed glass be floating of a layer of melted ice?
No, because ice has a thermal conductivity of 2.22 W/(m K) whereas foamed glass aggregate has a thermal conductivity of about 0.08 W/(m K) .
So the ice/foamed glass interface will stay quite cold and most of the temperature drop will happen across the foamed glass layer, assuming that it is a few meters thick or something. One issue is that in the very long-term you want to actively cool the upper layers of ice because the ice will start to develop a nonuniform temperature distribution.
Thanks. So will the building foundations be going through several meters of foam glass to the ice below?
The insulation may also be a type of concrete with foamed glass as the solid and a cement to fill the voids. This will then be topped with a much stronger layer of concrete. That concrete can be built on. Additionally that top concrete layer can be hollow for added strength and insulation. Think of a square grid of cells for the strength layer and a solid insulation layer underneath of the foamed glass ultralight concrete.
If you want to build a heavy building it may be better to just thicken that concrete topping layer than to penetrate into the ice, as the ice will be very cold (say, -40 degrees C) and you don't want to melt it. But Maybe there are special materials that will allow this to work. Certainly NOT metals though.
https://www.sciencedirect.com/science/article/abs/pii/S2352710223008562
Interestingly there was just a similar article in the news section of Science, about glacier geoengineering.
https://www.science.org/content/article/avoid-sea-level-rise-some-researchers-want-build-barriers-around-world-s-most
This is a very silly and inefficient way to lower the sea level though.
It's much easier to just reduce the incoming solar flux.
It seems to me that land of the same quality as this can already be bought for cheaper in many places. The post says the new land could be more valuable because of better governance, but governance is an outcome of human politics, so it's orthogonal to old/new land. In Jules Verne's Propeller Island, a power conflict eventually leads to physical destruction of the island.
it's orthogonal to old/new land.
No, because all existing land is already governed bv someone else and they don't want to let go of it.
But even existing land offers opportunities for new governance models. In 1917 for example, the existing land called Russia needed a new government model because people had become completely fed up with the old one. (The Communists has little to do with the overthrow of the Tsarist regime: that was almost completely a populist uprising -- and not particularly violent. Most of the violence came in contests over the nature of the next government model and in the winning party's consolidating its power.) The same thing happened (with much less violence) in 1989-1991. France needed a new government model in 1958: almost everyone agreed that the existing model did not work, and the new model (the Fifth Republic) was not arrived at through the workings of the existing model, but rather through a bloodless coup by the French military:
https://en.wikipedia.org/wiki/May_1958_crisis_in_France
Why would the government models used on the new land turn out any better than the model introductions I just described?
Why would the government models used on the new land turn out any better
Good question. Without significant innovation in governance they would not.
But innovation in governance is useless if there's nowhere to govern, so you have a catch-22 situation. The solution is to simultaneously introduce new forms of governance and new land to govern.
Well setting aside the legal/sovereignty issue, Antarctica is freezing cold, permanently dark for 6 months and gets covered in thick layers of snow every year. And it is not accessible to sea transportation due to a lack of rivers and railways.
It's just much worse land.
You could try to settle some of the outlying parts but the cold and dark and remoteness would still make it really bad land.
You can move your iceberg to the middle of The Atlantic Ocean and be close to Europe and America but also sovereign. That's worth a lot more.
I don't know why we think we can colonize Mars when we can't even colonize Alaska. Alaska at least has oxygen. Where are the domed cities with climate control?
It's not that we can't colonise Alaska, it's that it's not economically productive to do so.
I wouldn't expect colonising mars to be economically productive, but instead to be funded by other sources (essentially charity).
Alaska is also not politically productive because it's controlled by the US Government and they're definitely not going to want to hand it over.
Wouldn't it be easier to use a platform anchored in the ocean somewhere? If there's some law that it technically needs to have "land" you could dredge some sand like the Chinese did in their reclamation projects. Have a carrier-sized piece of land (and turn that into your central park) and build everything else on elevated platforms.
Yes you have to spend a lot to maintain that structure and surface, but I am still not convinced the ice structures require any less work to maintain.
Getting land somewhere else is still probably easier and cheaper. Have you looked into Svalbard? Are there any places that have notoriously sleepy governments and you could just make a compound there and do your experimental society? This ice structure thing seems pretty capital intensive, which makes me think buying land is still a better bang-for-the-buck.
Are there any places that have notoriously sleepy governments and you could just make a compound there and do your experimental society? This ice structure thing seems pretty capital intensive, which makes me think buying land is still a better bang-for-the-buck.
You can't really make a great new nation, startup city or network state in secret. You have to advertise it.
And if you are doing it against the wishes of the local government, that will discourage people from coming. This kind of effect even works if the locals are militarily weaker than you. Look at Israel!
Now there are some places where startup cities/communities are happening. Prospera is an example. But that requires some quite specific circumstances and isn't replicable. Legacy governments just don't want to give up control of their land. Another example is Liberland. Liberland could potentially be pretty good but Croatia hates it and they send police there to trash it even though they don't have a legal claim on the land.
If you want a nation-type org without the land you can start a cult or a religion. Mormonism sort of did this but they are ultimately still ruled by the US central government and it is gradually destroying them. If Mormonism was happening on an island it would be much more robust. Scientology is another example. They have their own compounds and own parts of various cities in the USA and the UK. Religious groups like The Amish are a further example - they use language and religion as barriers to keep foreign ideas and people out, but I don't think that is replicable at scale today because there's a decent chance that legacy governments would shut you down. So you can avoid the need for land to some extent but you will pay a large price.
I am still not convinced the ice structures require any less work to maintain.
It's not just about the maintenance requirements, it's also about the durability of the land and cost per unit area.
Seawater will destroy normal concrete over decades, so is not suitable. But there is a substitute, geopolymer concrete.
You can make floating platforms at sea using geopolymer concrete which is costed at about $200/m^3 for a compressive strength of 50MPa and about a 5MPa tensile strength (though you can improve that with reinforcement bars).
The problem with this is that you are paying $200 per cubic meter. If you want a really solid floating island that sits many meters above the ocean, each square meter of land will require multiple meters of concrete underneath it even with a mostly hollow structure. So you are paying over $1000 per square meter for your land assuming that is is 50-100 meters deep and has a 90% void fraction.
The Troll A Platform cost $1.2bn (corrected for inflation) for about a 250 x 250 meter useable area which works out at about $20bn per square kilometer of land area, or $2000 per square meter.
It has a dry mass of 683,600 tons of mostly concrete, which is about 10 metric tons of concrete per square meter of useable land area. For a 100km x 100km floating island that would be $20 trillion. It would use 100 gigatons of concrete, which is 1/5th of the total amount of concrete ever made by humans (550 gigatons).
Basically you are paying premium prices for this and I don't think it is economically feasible.
As for maintenance I think both ice and geopolymer concrete are going to be relatively cheap to maintain per unit area for very large islands. With ice the main worry is localized failure of your cheap bottom insulation job. But a small fleet of automated robotic submarines and a grid of temperature sensors can probably keep that in check. Remember you are already paying $ hundreds of billions for this so maintenance is going to be a rounding error.
I wonder whether, if sheer land mass really was the single dominant bottleneck for whatever your aims, you could potentially find a particular gov't or population from whom you'd buy the km2 you desire - say, for a few $ bn - as new sovereign land for you, for a source of potentially (i) even cheaper and (ii) more robust land to reign over?
"it has happened" is far less rare than CREATING the land, which has never happened. I think what most commenters are pointing out is that the mechanics of the ice-landmass are very difficult, but the overall proposal shares the majority of difficulties with non-creation ideas. Those difficulties are social and legal - the fact that other humans are GOING to interfere with your desires. Some of those other humans are going to join you and try to take over from within, and some will stay external, but will claim rights over your use and behavior from a distance.
other humans are GOING to interfere with your desires. Some of those other humans are going to join you and try to take over from within, and some will stay external, but will claim rights over your use and behavior from a distance.
well, yes, but having your own land massively impedes external enemies. This is why nations are a thing. Internal enemies cannot be beaten with mere mechanical engineering but that is not the topic of this post and again note that nations get stuff done despite having internal factions and enemies.
but having your own land massively impedes external enemies. This is why nations are a thing.
We have no clue how and whether this is true for new (or newly-valuable) land created in places that currently have international treaties about them. Geographic Sovereignty seems pretty iffy in at least one new-ish nation (Israel), and Ukraine may or may not be able to stay separate.
Having a dedicated nationalist population with historical willingness to defend seems to be the major impediment. This is easily conflated with "your own land", but the land is a prerequisite, not a cause.
Having a dedicated nationalist population with historical willingness to defend seems to be the major impediment. This is easily conflated with "your own land", but the land is a prerequisite, not a cause
Sure. But a population without land can easily be classified as criminals and subdued. Once they have land they are a nation.
The Kurds are a good example of this. Every nation-state with Kurds has a common interest in denying them nationhood so that Kurds won't claim territory or cause trouble.
Minorities in the USSR, in Anatolia in 1917 and many other places fall into the trap of being a people without land and pay for it.
So how expensive is 30-50MPa concrete in terms of pure raw materials at large scale?