Conclusion

The Jevons Paradox can be associated with the concept of ‘Malthusian instability’, an expression coined by Layzer (1988). Malthusian instability refers to metabolic systems which are able to reproduce themselves (all living systems). It indicates that when operating in favourable conditions, they will unavoidably surpass the carrying capacity of their environment. This entails that the resulting process of natural selection will determine a constant evolutionary stress on metabolic systems. That is, there is a natural tendency of living systems to ‘get in trouble’, and this is the mechanism that enhances their ability to adapt and become something else. At the level of the individual metabolic system, this Mathusian instability is made possible by the existence of activities that in energy terms provide a positive return. In technical jargon we can say that these activities are generating a positive feedback or an autocatalytic loop. For example, if you invest 10MJ to perform an activity and you get 100MJ in return from this activity, and then if you re-invest the 90MJ of energy profit in doing more of the same activity, then you will get a total energy return of 900MJ. It is well known that a positive feedback like this one cannot go on unchecked for a very long period of time. We can recall here the story of Zhu Yuan-Chang’s chessboard: if you put one grain of rice on the first square, two on the second, four on the third, and keeping doubling the number each square, there would be an astronomical number of grains of rice required for one position even before the 64th square is reached. This metaphor says it all. Hypercycles, or positive autocatalytic loops, when operating without a coupled process of control (and damping), do not survive for long; they just blow up (Ulanowicz, 1986). On the other hand, positive autocatalytic loops are required to provide the required supply of energy for those activities that are useful, but that implies a net loss of energy.