Recycling Under Scarcity Conditions

As noted in a different post, scarcity is the death knell of alien civilizations. When the resources that they can tap diminish below a certain threshold, the civilization can no longer function. Substitution of more plentiful, but less useful, resources would be done as the most useful but rare ones are depleted, but then, eventually, the substituted resources also begin to grow short, and the search for different substitutes ensues. This process may go on for millennia, but eventually it dies out.

Migrating in one form or another to a different planet can preserve some of the signatures of the civilization, but migration also induces great changes in the civilization. For that matter, so does scarcity. Much has been written in this blog about how alien civilizations might or might not rise to the point where they can consider star travel, but very little about how they could lose this capability once they have gained it. Yet, to determine the likelihood of interstellar voyagers coming to Earth, it is necessary not just to know how many alien civilizations exist and have reached the ability to travel from one solar system to another, but how long they could do it, and what happens to them that takes away the star travel option.

What this means is that the back end of the history of an alien civilization should be given as much attention as the front end. The front end has many, many times as many interesting challenges as the back end. Some of the possible back ends, namely the various galactic, stellar and planetary perils, have been discussed in this blog. One of the possible barriers to an alien civilization reaching star travel, idiocracy, could possibly be resurrected later to cause the loss of the star travel option; the details of post-asymptotic technology idiocracy need to be ironed out.

One aspect of the back end, perhaps the only universal one, is resource consumption and depletion. This comes from the discussion of time scales, which is one of the tools developed to properly speculate about alien civilizations. Geological recycling takes too long. An alien civilization cannot sit around waiting for some basalt flood to pour new resources out on the planet’s surface for them to mine. Geologic time is hundreds of millions of years; alien civilization time is tens of millennia.

What exactly does the downslope of an alien civilization look like when scarcity starts to occur? One way that might be considered as a solution is recycling. Recycling slows down the usage of materials by reusing some percentage, hopefully high, of the discarded exhaust of the civilization. It covers everything, although recycling does not need to get started as early with plentiful resources as with rare ones. Plentiful means that the total amount available compared to the annual usage is huge. Annual usage is the amount needed to fill in the losses that occur in the recycling process. This means that going from a 90% recycling situation to a 99% recycling situation extends the lifetime of the alien civilization by a factor of 10.

Not quite. Recycling is not free. To use an oversimplified example to clarify this point, consider going from a 90% situation to a 99% situation, after the alien population realized their dire straits and decided to see what they could do to alleviate it. To go to 99% means that more recycling has to be done, and harder recycling. Getting the next 9% done might cost more energy and more resources that getting the first 90%. Extracting more and more of something from a finite resource is more and more costly.

Recycling materials has an analog in extracting materials in the first place. There are places where some type of mineral might be easy to extract, where the percentage of the desired element in the ore matrix was high. After they are gone, ores with a lower percentage are available. If the percentage of desired material drops by a factor of ten, that means that ten times as much ore has to be processed to produce the same amount of material. That is a cost factor, meaning either some more currency, which might be equivalent in an advanced civilization to energy, has to be produced, or some other costs have to be reduced. Either build more reactors or accept a lower standard of living, which is also measurable in energy.

Building more reactors is not free either. A fusion reactor takes resources to build, and that means cost, which means energy. After a while, the number of reactors gets to be unacceptable. The total energy cost of the reactor gets to be comparable to the net energy it produces. Building it is a waste of time.

Recycling better and better is also something which has a limit. Because recycling to a high degree consumes resources, there comes a time when an increase in the percentage amount of recycling becomes too expensive.

At this point, it is best to remember the concept of asymptotic technology. This means recycling technology doesn’t just get better and better, in the sense of recycling produces less and less loss with no other consequences. There are consequences, and the consequences are that resources and energy are used up in the recycling facilities, along with all the transportation that has to accompany it. It also has consequences in design of all the infrastructure and goods produced by the civilization. If something is being designed to fit into a plan which allows 99% of the materials to be recycled at low or acceptable costs, that design would have more severe limitations that a design which is made for a 90% plan. Even the activities that go on in the alien civilization have to be limited. So, the bottom line is that some level of recycling is useful, and the level that is achievable depends on what the material is, but there is no technological rescue possible. Technology will delay the collapse of the civilization, through recycling and many other ways, but it is something like a single order of magnitude extension. In other words, if an alien civilization can go on blithely using up resources for three millennia before they become dirt poor again, using all the tricks of recycling and social organization and so on might extend it to thirty millennia.

Life and death of an alien civilization, or specifically the onset and termination of their capability for space flight, occupy a short window of time. How long this window might be deserves to be examined well, as it seems to be a dominant reason for the lack of visitors from far away.