This is an excerpt from my book on Mars industrialization. It goes into a lot of detail on how we can think about the interaction between hostile environments and technological sustainability.
Iceland is an apt analogy for a potential Mars city, and a useful way to think about self-sufficiency. Today, Iceland enjoys a high standard of living and is a popular tourist destination famed for its natural beauty. It has a population of about 335,000 and a GDP per capita of about US$60,000. Naturally, it is highly dependent on a range of imports, exporting mainly aluminium and fish.
Further, Iceland is similar to a city on Mars in that it is relatively small, isolated, and cold. It is not a perfect analogy, as it also has breathable air, mainly basaltic geology, and abundant readily accessible geothermal and seafood resources.
It is clear, however, that if Iceland was cut off from international trade, its standard of living would rapidly regress to that of the 19th or 18th century, as first petroleum was exhausted, then parts of the electrical infrastructure suffered failures necessitating parts that could not be made locally.
While many of the goods upon which Iceland depends could be made locally with some forward planning, some parts are truly “magic widgets” that are very difficult to make. The smallest nation that is able to make, for instance, a sufficiently complete set of computer components is probably Japan, with a population of 127 million and a GDP per capita of US$39,000.
In 2018, the world’s largest containership is OOCL Hong Kong, with a cargo capacity of nearly 200,000T. This behemoth can carry, on a single voyage, about as much cargo as I can imagine 50 years of BFRs bringing to Mars.
Here is the thought experiment. Given one large containership of any desired cargo, can one devise a strategy that will forestall Iceland’s post-isolation living standard collapse indefinitely? Can one fit, into a single ship, a complete industrial stack and the tools to run it with a relatively tiny population? It seems like a tough problem, but achieving autarky in Iceland is a much easier task than doing it on Mars.
Population, technology, and environmental hostility
The Icelandic question is a good starting point for a broader discussion of the interplay between population carrying capacity, technology, and environmental hostility.
First, consider the relationship between population and technology level in a given environment, holding hostility constant. For any given level of technology, there is both a maximum carrying capacity (Malthusian limit) and a minimum population required to sustain that technology. In this sense, technology is a disaggregated knowledge base that must be propagated through education even as individual practitioners are born or die. Technologies that increase carrying capacity include germ theory, mechanization of agriculture, and the Haber process for producing nitrate fertilizers, but in practice it is not useful to attempt to be perfectly granular about such a rich constellation of practices.
Provided that the carrying capacity at any level of technology always exceeds the maintenance population, there is a surplus of labor to invent new technology and a stable “band” in which the population can survive without losing or gaining technology. Outside this band, however, the population or technology will fall until stability is achieved. If, for example, Iceland were to suffer a repeat of the 1784 eruption of Laki, environmental fluorine poisoning would increase hostility and reduce carrying capacity, manifesting as a prolonged famine and substantial fall in population.
The asymptotic behavior of this graph is not well defined, so it has limited utility for predicting the far future of humanity. In particular, it is possible that beyond a certain technology level, the minimum population level stabilizes as computers are doing all the work. On the other hand, it is clear that there is a finite limit on the population capacity of Iceland, the world, or the universe, set by fundamental thermodynamic and volume constraints.
Second, consider the relationship between population and environmental hostility at a constant technology level. This graph shows a markedly different behavior to the previous figure. As the environmental hostility increases, the carrying capacity decreases, which seems obvious. What is less obvious is that because individual worker efficiency falls in hostile environments, the minimum population required to support a level of technology increases.
On the left part of the graph, the situation is similar to the previous case, with a band of stable population. Moving to the right, the limits converge at the critical hostility level, beyond which there is no stable population size. The early North American colonies Jamestown and Roanoke straddled this point.
As technology level changes, the critical hostility point traces out a trajectory demarcating the fully generalized limits on population and hostile environments.
How do we interpret this in the case of Iceland being artificially isolated from the rest of the world?
Iceland’s imports of advanced technology help to insulate Icelanders from the hostility of their environment. This makes it more livable at a higher standard of living, at the cost of dependency on an extrinsic supply chain. If this technology became unavailable, then Icelandic people would be compelled to operate in a more hostile environment, with the associated labor and health overheads that implies.
This graph shows the full relation between population, hostility, and technology. For any given level of technology there is a family of curves that together define the stable region. As Technology increases, I have suggested that maximum population carrying capacity drops off more gradually with increasing hostility. That is, increased technology lessens the sting of increased hostility. Conversely, the minimum population to support the technology increases more quickly with increased technology, because of the increased complexity of co-dependent industrial processes. In combination, the critical hostility increases with technology, as expected.
This is only a simple, qualitative diagram. A more precise calculation of the system may reveal cusps, stable points, and multiple pockets of relative stability with voids in between. It’s also imprecise to force all of technology onto a single dimension, since environment-specific technologies are more relevant for solving a given problem. Despite the imprecision of this diagram, it does deliver one key insight, which is that management and amelioration of the hostile environment is vitally important for reducing the overall cost and population needed to reach autarky.
It is clear that the vast majority of human labor on Mars should be performed in as controlled an environment as possible. That is, the city is built within a series of enormous, pressurized structures that enable comfortable, safe, efficient shirt-sleeves operations. Even mining operations would be preferentially operated within pressurized tunnels unless automated surface mining machinery reached a sufficiently high level of reliability. Yet establishing a local supply chain for essentially all the chemical elements will require hundreds of labor intensive, hostile mines, and some in remote places. For that reason, the labor requirement with primary resource extraction scales much more aggressively than for secondary manufacturing. Complexifying manufacturing, once large pressure vessels exist, is mostly a matter of direct translation from Earth analogs in a shirt-sleeves environment, and comes with a much less stringent labor requirement.
Is it even possible to build and maintain a habitat on Mars with a sufficiently benign environment for humans to get on with the job? Although the answer seems trivial, there is an overhead for building walls to keep the air in, and this overhead increases as the environment gets more hostile. For instance, it is probably possible to do this on Iceland, or Mars, or the Moon. But a comet? Or isolated city in deep space? What about on the surface of Io, or inside Jupiter, or the bottom of the ocean? While I am sure that a human terrarium on Mars is doable, I am quite sure that no amount of technology would permit humans to build an industrial city inside the sun.
Detailed Icelandic prescription
To return to the Iceland question, what 200,000T of stuff should be obtained to survive a period of indefinite isolation with minimal reduction in standard of living?
Let’s look at trade to get some ideas about what Iceland will miss the most, and to understand what needs to be duplicated locally. Here’s a treemap of Icelandic imports in 2015, which groups by sector and ranks by total value.
As expected, the major part of Iceland’s imports are connected to its role as one of the world’s largest smelters of aluminium, an energy intensive industrial process that exploits Iceland’s cheap electricity. Iceland exports nearly all its aluminium, so it’s not clear that retaining that industry would be a high priority in the event of total isolation.
The next most salient component is refined petroleum, cars, and other heavy machinery. This component concerns the obtaining and disposal of energy for useful work. Iceland has an abundance of electricity, but gasoline remains the universally preferred way to fuel mobile machines. These machines increase the per-capita work capacity of humans by a factor of 10-100, so it’s clear that maintaining a modern standard of living will require some way to fuel them. This is the single largest challenge for Iceland, and also for a city on Mars. In Iceland’s case, a mixture of high power electrical umbilicals at work sites and battery driven hydraulic power units are probably the best way to retrofit existing machinery and ensure the continuing availability of industrial capacity.
The next largest category are manufactured goods, including parts, electronics, appliances, chemicals, medicines, and so on. A simplified local manufacturing capability for some minimum viable combination of these must be designed. This is a tough problem!
The next largest category are raw structural materials, including metals, plastics, and textiles. This is particularly challenging as Iceland does not have commercial deposits of mineral ores or onshore oil. Limited quantities can be produced from non-standard feedstocks, but it will be labor and cost intensive. This is also a tough problem. While Mars is believed to have ores concentrating all the usual minerals, it does not have a global supply chain so settlers will be limited by what they can access in the immediate vicinity of their base.
The Iceland National Statistics Institute has 4468 categories of traded goods, including live primates, trichloropentafluoropropanes, and nine categories of cranberry juice. A detailed discussion of alternate sources for every last product is beyond the scope of this chapter, but does underscore the utility and diversity of modern trade.