(1.1-006) Leverage Points
Unless the biological components of the life support system of an Orbital Habitat are deliberately kept simple (see 1.1-001 - Rule 3) they will quickly form a complex system. Such systems cannot be managed in a similar manner to the components of the technosphere.
Donella Meadows in her seminal paper[1] clearly outlined the problems with direct intervention in complex systems and detailed far more subtle and effective ways to approach the management of such systems.
Listed below are Meadows Intervention Levels (4.2-001) (in order of increasing effectiveness). The commentary on the Intervention Levels is focused on the management of a population of a species (primarily via water level adjustment) in a Biologically based Life Support System. This is just an example to provide a consistency for the discussion - there are, of course, many other things which could be managed.
It is a very good idea to read Donella Meadows paper before reading the summaries below.
Places to Intervene in a System
12. Constants, parameters, numbers (such as subsidies, taxes, standards)
This is the goto response of pretty much everybody when attempting to change the behavior of a complex system and it is generally considered to be the least effective. In the context of managing a biological life support system it is the equivalent of adding or removing individuals of a species in order to achieve some sort of desirable balance. Yes, it might work, but in general it is extremely labor intensive and costly.
11. The sizes of buffers and other stabilizing stocks, relative to their flows
In a CELSS, an example of changing the size of buffers would be deliberately reducing the water available to the system without regards to its state (liquid or vapour). As the system self-adjusts to the new stock levels the induced drought or flooding would affect the population of a species or its productivity. It is easy to see how this is a bit more abstract than an intervention at Level 12.
10. The structure of material stocks and flows (such as transport networks, population age structures)
In part, this Intervention Level refers to the physical layout of the flows in the system - sometimes these are hard or impossible to adjust. In the context of a CELSS, it could be the layout of the streams or lakes created when the biome was constructed. Perhaps, using the example of water, it would be possible to have various outflows situated around the perimeter. These could be turned on and the water could be allowed to find its own way into the sinks. Note this is different than an intervention at level 11. The amount of water is the same but the route it takes through the biological system is different. It is also possible to imagine that the condensation points for water vapor could be managed to provide the outflows thus inducing changes in the water sources for the biome.
9. The lengths of delays, relative to the rate of system change
This particular leverage point refers to the oscillations due to the difference in the time it takes an action to result in a response. For example, it could take a considerable amount of time for an artificially induced drought to affect the population of a species. Timing is key here - too long a drought and you might eliminate all of the target species and too short and you might not remove enough. The problem, in this example, is that the length of time it takes to observe a response from a given stimulus greatly complicates matters and oscillations can ensue. An intervention at Level 9 could seek to reduce the feedback delay - perhaps by inducing severe harsh droughts in localised areas. Another alternative might be to simply acquire enough data that an usable PID control model can be used to help predict the future results of an action and help minimise the oscillations.
8. The strength of negative feedback loops, relative to the impacts they are trying to correct against
This is where the leverage points move into the area of control and reaction to information. Instituting negative feedback systems and then adjusting the parameters can be a powerful way to control a complex system. In the context of the ongoing example of species control, an example of a negative feedback system would be the introduction of predators for that species. The system would probably soon move into a Lotka-Volterra predator-prey mode of oscillation. The strength of the negative feedback loop could be adjusted by the choice of predator or by a Level 12 intervention controlling the predator population rather than directly operation on the target species population.
7. The gain around driving positive feedback loops
Positive feedback uses a change in something to further induce more change in that thing. This is the opposite of Negative Feeback (see Level 8). Usually the desire is to limit positive feedback since continuous increase inducing more increase (or decrease inducing decrease) soon runs into hard limits - either the system runs out of resources to increase or the quantity of the value being controlled hits zero. In the example of species population control one might attempt to find a way to adjust the ability of the target species to reproduce. If one wished to increase the numbers providing increased or decreased nesting sites would adjust the positive feedback gain upwards or downwards.
6. The structure of information flows (who does and does not have access to what kinds of information)
This leverage point would seem only to affect the actions of individuals who make decisions based on environmental inputs. However, the actor does not have to be "intelligent". Various animal species decide to mate or feed based on environmental input, plants are known to be receptive to the hormones output by neighbours under stress. It is increasingly well documented that sub-soil fungal webs communicate over a wide area.
Enhancing or inhibiting the ability of the system to issue such inter and intra species communications would be an intervention at Level 6.
5. The rules of the system (such as incentives, punishments, constraints)
This particular leverage point would seem to primarily applicable to intelligent (but not necessarily self-aware) beings who can adapt their behavior according to punishments and rewards. Ecosystem components such such as plants, fungi or microbes would not probably be amenable to interventions at this level. However, higher animals can be trained - perhaps a system of operant conditioning could be used to move behaviors in desired directions. Certainly rewards and punishments can be used to modify human interactions with a closed ecosystem.
4. The power to add, change, evolve, or self-organize system structure
It would seem that a biologically based life support system would be ideal for interventions at this level. Meadows[1] puts it very succinctly:
The ability to self-organize is the strongest form of system resilience. A system that can evolve can survive almost any change, by changing itself.
Self-organization is basically the combination of an evolutionary raw material a highly variable stock of information from which to select possible patterns and a means for experimentation, for selecting and testing new patterns.
Introducing new species and letting the ecosystem adjust and self organize is an example of an intervention at this level. For example, if you wished to raise the humidity of a biome you could consider introducing more deciduous trees to transpire water vapour[2] . Of course, in doing so, you are introducing lag between the action and the effect which is hard to work with (see the discussion of Level 9).
It is not just the choice of new species to add which is an intervention at this level. The method of introduction of new species (Bead Stringing or Shotgunning (see 4.2-001)) directly affects the interactions of a biologically based life support system at this level.
3. The goals of the system
The goal of the system largely dictates the direction all interventions at higher levels take. For example, if the goal of the ecosystem in the biome is simply to continue to exist then one type of higher interventions might be appropriate. If the goal of the system is to preserve certain rare species or maximize food or O2 production then the interventions at higher levels will likely take other forms.
The goal of the system is rarely stated at the outset - but it really should be. Realize that if you change the goal of the system (perhaps due to necessity) then all management methods at all intervention levels need to be re-assessed for appropriateness.
2. The mindset or paradigm out of which the system —its goals, structure,rules, delays, parameters—arises
This intervention level is extremely powerful - as discussed in Level 3 the goals of the system are almost never specifically stated. The mindset behind that goal is even more rarely examined. Interventions at this level are largely focused on the human managers of the system: What do they believe is "right" for the system. Change that belief and you change the goals at Level 3. Change Level 3 and you affect all of the higher intervention levels.
1. The power to transcend paradigms
Sooner or later every human endeavour ends up with philosophy. It is difficult to improve on Meadows[1] discussion of this Intervention Level so a section of it will just be quoted here.
There is yet one leverage point that is even higher than changing a paradigm. That is to keep oneself unattached in the arena of paradigms, to stay flexible, to realize that no paradigm is “true,” that every one, including the one that sweetly shapes your own worldview, is a tremendously limited understanding of an immense and amazing universe that is far beyond human comprehension. It is to “get” at a gut level the paradigm that there are paradigms, and to see that that itself is a paradigm, and to regard that whole realization as devastatingly funny. It is to let go into Not Knowing, into what the Buddhists call enlightenment.
Resources
References:
1. Leverage Points: Places to Intervene in a System, /papers/378
, Sustainability Institute2. Nature Scientific Reports, Deciduous trees are a large and overlooked sink for snowmelt water in the boreal forest , accessed 2024-04-24