Alternatives with Arcologies

Somewhere along the pathway from hunting to asymptotic technology, an alien civilization must realize the threat that resource exhaustion poses to their living standards and the status of their civilization. One of the responses to this threat is the adoption of recycling to reduce new resource consumption and substitute re-use and re-cycling.

If recycling is done on a civilization-wide scale, with all citizens participating in the same processes, the efficient organization of the civilization is to have everyone living into cities, structured like arcologies, with the logistics pathways for all goods and waste short and efficient. Efficiency is one of the other tools that the resource exhaustion threat demands.

If the assumption is relaxed that all citizens participate in the large-scale recycle in identical fashion, the concept of universal arcologies becomes superfluous. If the population is large, of the order of ten billion citizens with energy consumption rates perhaps ten times that of industrial civilizations on Earth, then the large majority would have to live in arcologies, but there could be a minority living with disaggregated recycling.

Another factor that might be decisive on the need for arcologies and the fraction of the population living in them is the final trade-off made between robotics and genetics. Robotics need manufacturing centers, but biological solutions to accomplishing some of the civilization’s tasks might need only some facilities for growing the proper organisms, and even these might be biological as well. If some of the population were dispersed, then recycling of all biological goods might be equally dispersed, and only manufactured goods would have to be transported back to some recycling centers, perhaps located in one of the arcologies.

The transportation costs might be ameliorated by some biological conversion of carbon dioxide in the atmosphere to oxygen and separated carbon compounds. This is exactly what photosynthesis does, but if it could be powered alternatively, such as by fusion-generated electricity, it would be more under control of the civilization. Once this was accomplished, some minimal amount of carbon compound liquids or gases could be used as the excellent energy storage medium they are, and a certain amount of transportation could be arranged for to accomplish the recycling of manufactured goods.

Manufactured goods would be designed for efficiency from a whole-life viewpoint, as opposed to what would happen in early industrial times, when the design viewpoint might be manufacturing efficiency or once-through consumption efficiency. If a manufactured item is designed without re-use of parts and recycling of everything else in mind, so that re-use and recycling costs are very high, then the total lifetime costs are very high as well, as the end stages dominate the cost cycle. If instead, manufactured items are designed with a full life-cycle in mind, meaning that a closed loop of resources is attempted, without only energy inputs plus a very small amount of resources to fill in impossible-to-control losses, then there is little energy cost expended in extracting resources and transporting them, as well as processing ores. Instead, the civilization’s energy use is more devoted toward immediate consumption plus recycling costs.

Consider the fraction of the alien population which is dispersed in whatever natural surroundings evolved on their planet. Aside from manufactured goods, everything else in the consumption arena can be recycled in the natural surroundings. Whatever they need for nutrition can be produced either from the surroundings or from wholly biological means, either involving the surroundings or in special micro-facilities, and either using evolved genetics or designed genetics. Most likely the most efficient way of organizing a community living outside the arcologies would be strongly dependent on the locale, the climate, the environment, and other factors that differ all over the planet. Community size could range from an individual, living outside the arcologies for some period of time, up to groups numbering in the order of thousands. Too large an outside community would seem to break the ecology of the area.

There would be costs of moving everything that needed to be moved between the arcologies and the dispersed population. These involve the two-way transport of manufactured goods, plus population transportation and the transport of specialized goods, like seeds or certain biological materials. The transport vehicles would likely be manufactured goods, which would be produced in the arcologies, and recycled there. Energy could be anything simple, such as hydrogen gas for land surface vehicles and carbon compounds for either land or air transport.

Energy production in the dispersed areas might be either locally gathered energy, or transported energy. If energy was not produced in the dispersed areas, this might be the largest single item for transportation. One example might be the frequent transportation of hydrogen gas to the dispersed areas, where it might be transferred from the transport vehicles to community tankage. Just how much energy such a dispersed community might need is probably beyond our estimation ability. If the community was largely utilizing biological means to provide the means of living, then photosynthesis might provide a large part of that energy. Other means of collecting energy from their star’s fusion could happen, but the efficiency that could be achieved is not easily guessed. Given a total control and understanding of genetics, how much of the solar energy falling per meter of planetary surface could be absorbed and turned into accessible energy or carbon-based products?

A few hundred million years of evolution has pushed the efficiency of Earth plants to a range of 0.1 to 2% conversion of solar photo-energy to carbon biomass. A different star would have a different spectrum of light, which affects conversion efficiency. Furthermore there is a second efficiency which relates to the utility of the carbon biomass the plant or other organism produces as far as the uses to which the alien civilization has for it. This efficiency is also low and highly variable, but for bred crop plants might get to a few percent. How much higher could this be pushed with a complete knowledge of genetics plus the ability to design and construct any genetic concept? This number indicates what the collection area might have to be for a community of a given size.

What are the extremes that we might observe with a giant telescope on a planet found to have an alien civilization? One is a planet with nothing but arcologies, perhaps hundreds, all of which would be emitting heat and serve as thermal point sources for the telescope. The other end is a planet with only one arcology, where all manufactured goods were produced, and the remainder of the population dispersed and making use of mostly biological organisms for their life support. Either could be the choice of the governance of the planet, and there does not seem to be any reason why a particular planet could not go one way or another, or more likely, something in the middle. The latter extreme case would have only one thermal source to observe.

Another way to consider alien options is to consider the design of an arcology. Could one be cubic and another be large, low and flat? Something to be considered at another time.