On Sustainability as Peacock-mutualism

This is a note on Prof. K. A. Peacock's article:
Sustainability As Mutualism Between Humans and the Earth:
or, Can We Be the Forehead Mites of Gaia?

Dear Prof. Peacock,

I read your paper and your notes to Prof. Lorenzo Matteoli. Maybe you have read the notes I sent him too.

I think that your analysis of the notion of Sustainability is one of the best that I have read, from a Sustainability point of view.

However, I have something to say about the whole thing. As you may have already guessed, I am quite skeptical about Sustainability, even if I am not skeptical for the sake of a 'business as usual' approach. I wish you were right when you and your Sustainability colleagues claim that Sustainability is possible, and you suggest the biological concept of mutualism as a possible answer (whatever mutualism may be, which is far to be clear and self evident in scientific terms: that is outside an eco­ethical perspective). For sure it may be desirable for someone, but I fail to see how it could be possible whereas it seems easy to you. And I am not talking only about political reasons, should political reasons be just a minor technical problem. I even fail to see how Sustainability could be a physical problem easy to isolate from political considerations, as you claim.

I am writing a lengthy note about the notions evoked by your paper. It will be available on my WEB page probably in the next few weeks. Anyway I have made some of my points in the notes to Prof. Lorenzo Matteoli that he forwarded to you. Some further elaboration may be found in my paper on Sustainability that can be down loaded from my WEB page. What follows is some more thinking on the matter, and it is what it will go in my note.

According to your definition, Sustainability is a way to meet the needs of the present generation without compromising the possibility for future generations to meet their own needs. You claim mutualism could be the answer to the problem. You make the example of how alga and fungus cooperate in lichens. Since humans cannot directly metabolize solar energy, your idea of mutualism would allow to pump­in negentropy from solar energy through the cultivation of plants doing at planetary scale what algae with fungi do in lichens. Mutualism should be the result of widespread cultivation of the Earth, with humans acting as valves and modulating devices of the process. For example, planting trees that would reduce the otherwise scattered and wasted solar energy that falls on barren lands. Your assumption seems to be that this activity could convert -- and make it available to humans through its byproducts (oxygen, carbohydrates) -- a greater amount of solar energy than now. The reduction of Earth albedo should be a consequent effect and prove the efficiency of these new cultivation techniques.

Your main concern is to physically isolate the problem. In this way, you argue that mutualism is physically possible because the Second Law of thermodynamics is not violated, since the Earth receives free energy from the Sun. This because it is a dissipative, far­from­equilibrium structure, quite different from a self standing canister of gas. Your formulation has an equivalent formulation in the statement that we could somehow keep up with the entropy degradation of the solar system, if only we adopted mutualism. Consequently you say that, if this new global design approach is not taken, we will not be able to keep up with entropy degradation of the solar system. You seem to suggest that if we will not be able to do it, it will be for socio­political reasons, not for physical reasons.

You are right when you say that the Earth is not an isolated, self standing canister of gas. In fact, it is not a closed system, at least for the reason that it is invested by solar radiation. Perhaps it could be considered a closed system at the solar system level. Hence, relevant thermodynamic considerations should be made at that level.

However, biological organisms, and biochemical life as we know it, are subject to additional constraints along with the Second Law. For instance they cannot stand long exposure to high energy radiation. They survive only within a very narrow temperature range. They need water. They need several different kinds of gradients (concentration of chemicals, temperature, pressure, etc.). This is just to mention some elementary physical condition beyond the Second Law necessary for biological life to develop and be sustained.

At the core of what we know as life, there have to be molecular structures capable of replicating with variations and developing auto­catalytic reactions. So elements are formed according to chemical laws, with different self­replicating molecular structures that compete to capture other molecules present in their environs. This elementary mechanism produces local concentrations of organized chemical compounds by chance and as a function of specific environmental conditions. Like a recursive function, this mechanism applies over and over to the very objects it produces, thus possibly yielding growing complexity. We may call this basic mechanism the 'Darwin machine'. This is also the fundamental mechanism of the pump effect on free solar energy that you characterized. The effect that you call 'pump­in negentropy' and consider a virtuous thing. However, these basic conditions seem also quite hostile to the development of any form of mutualism.

All these constraints are irrelevant for a simple physical system to work. They may or may not be present, without violation of the Second Law. They are not irrelevant though to biological organisms (which are complex physical systems with non linear dynamics), and may end up having 'political' consequences in a way that cannot be easily brushed off as trivial.

The Second Law may play a major role in a more subtle way. Biological organisms are far­from­equilibrium thermodynamic devices and the Second Law is still valid when we deal with the macroscopic world at the scale of biochemistry. So they can decrease entropy only locally at the expenses of some part of their surroundings, notably if they are heterotrophs and the top of food chains as we are. Even if they receive direct solar energy, as plants do, they must compete for their share of Sun against some other plant. In fact, the grass grows greener and thicker in the place of the fallen pine tree.

Why should a biological individual give up its share of energy, if not forced by some kind of conflict, or predatory action? How can you expect it will do it for the sake of an abstract notion like mutualism or of some other abstract notion like the 'benefit of the species' or the 'survival of the Earth'?

Available solar radiation per time per surface unit is non unlimited, and great part of it is already swallowed by the ecosystem as it is now, even if, perhaps, it is not mutualistic in the meaning you give to the term. Solar radiation is further limited by the geometrical and kinematics considerations on the shape and movement of the Earth. In addition, other biophysical constraints may apply. For example you cannot grow layers of trees over and over without limit.

To reduce the albedo of the top of the clouds, or of the Sahara sand, or of the Antarctica snowy plains, by cultivating rain forests may not be as easy as in theoretical thinking. Of course this does not seem to go against any fundamental physical law, at first glance. However, I think that if rain forests could grow there, they would have grown already. Even without being cultivated by a brand new mutualistic agricultural engineering to help pumping up negentropy in the ecosystem, acting like the base of an eco­transistor.

Oases perhaps could be regarded as an example of mutualism. Oases in the Sahara desert survive thanks to very complex cultivation techniques evolved in several hundred years. That relationship with the environment seems to satisfy your notion of mutualism. However, why didn't the oases spread over to the entire desert? I suspect that they survived because they were of vital interest to desert travelers when the desert was a commercial highway. Thus oases continuously received extra free energy from caravans in some form (energy extracted from more favored places outside the desert and left there as money, goods, etc.). We may look at them as loss sinks of the energy paths through the desert. An accurate and detailed balance of the resource flows that allowed these jewels to survive for such a long time is very difficult to carry out. There may be diverse and contradictory explanatory models, and this balance may be heavily affected by small uncertainties of input data. Could oases have survived for so long if they had been completely isolated, without those or other similar links? Could oases be the model of a sustainable environment for 5.5 billion humans without any back­up free energy supplied by fossil fuels?

Somewhere in your paper you say that even aboriginal cultures, with low population densities and very light technology apparatus can have a significant positive or negative impact on supporting ecosystems. You say that not even commensalism (not to speak of current near­pathogenic parasitism of humans over their ecosystem) could solve the problem, because humans are too many. Only mutualism could do it.

But how can you be sure that the mutualism you propose may indefinitely support all the humans that our complex economies hardly can support now? In my opinion, it's going to be very hard even with abundant flows of free low entropy energy supplementing the Sun. My opinion, strongly supported by evidence, is that the heterotrophs humans of the XX century, are ephemeral biological devices snugly fit to a very complex ecological niche endowed with temporary abundance of fossil fuels.

Let's try some rough estimate of the orders of magnitude involved by the assumption of long lasting mutualism. It is not easy because we have to deal with great uncertainties and with the dynamic balance of complex systems for long times. Anyway, let's try.

I suppose that the main goal of mutualism could be the substitution of the yearly consumption of fossil fuels with an eco­compatible equivalent Biomass, the yield of hypothetical cultivation of barren lands. In fact, fossil fuels are not typical renewable sources: the natural environmental process requires a long time to restore what we annually burn now. Hence, from a human viewpoint, fossil fuels are an exhaustible source of free energy added to the annual flow of solar energy. Thus fossil fuels are not the best means to keep up with the entropy degradation of the Sun, which seems to be the main concern for the adoption of mutualism.

However, fossil fuels result from a pumping process of solar energy into concentrated low entropy forms, like hydrocarbons and coal. Exactly the same pumping process that is the basis of the proposed mutualism. The ecosystem made this pumping process in several hundred million years.

It seems reasonable to assume that current conversion of fossil fuel influences current food extraction pattern in a complex way and allows a greater food production than without them. The food extraction pattern feeds now 5.5 billion humans. Correlation between growth of fossil fuel conversion since industrial revolution, and growth of human population is very close.

Furthermore, it seems reasonable to assume that conversion of fossil fuels is not a completely unmotivated dissipation, since humans make wars for its control. To operate this complex worldwide economy -- with the yearly flow of solar energy that goes into the food chains -- we have been burning, in less than 250 years, the produce of several hundred million years of solar energy pumping activity. Of course we can expect to increment our global conversion efficiency. Anyway, it would be very difficult to design a long term solar energy pumping activity that is 10⁶ times more efficient than the natural pumping activity that produced fossil fuels. It is very optimistic to think that we will be able to produce fuel­like low entropy storage of the needed size simply by reforesting barren lands.

The Biomass converted into fossil fuels during hundred million years is only a small fraction of the entire Biomass that grew on Earth in the same period. From a limited engineering point of view we could convert a greater Biomass into fuel­like energy. We can use photovoltaic solar collectors, instead of Biomass. In the future we can expect to use the low entropy of fossil fuels with higher efficiency and with a more appropriate energy cascading (an example of energy cascading is the use of waste­heat of thermodynamic engines for district heating by co­generation plants).

However, we cannot rely on any certainty that the ecosystem could support this for long periods. One risk, for example, is to select monocultures that could become attacked by new uncontrollable parasites. Certainly, we could not expect to control these processes for periods comparable to the life of the Sun. From such a standpoint even pre­industrial agriculture could be considered a parasitic activity damaging the ecosystem. However, keeping up with entropy degradation of the solar system is a target of mutualism. Even more: it is the 'raison d'être' of thinking 'mutualistic'.

From intensive cultivation of conifer forests we can expect some 4÷5 [MJ/m²·year] of low entropy concentrated energy comparable to fossil fuels (maybe we can get something more if we choose other more labor­intensive vegetables and other distillation technologies more efficient than charcoal­making). If we consider current world energy conversion of 3·10⁸ [TJ/year] -- almost all from fossil fuels and few other scarcely renewable sources -- we would need half the surface of Earth's emerged lands for conifer forest plantations. Considering as deserts some 30% of emerged lands, we would need land in excess of the total desert lands on earth. In other words we would need an equivalent of 1.6 times the entire surface of present deserts. If we had to serve each individual of the world population with the same amount of energy that is now used by the average US citizen, then we would need an area equivalent to 2.6 times the surface of all emerged lands, or 8.7 times the surface of deserts. It is clearly another Planet.

This taking for granted that growing something comparable to conifer forests in the Sahara desert would not be a problem. But what about the fresh­water and the fertilizers needed to grow and irrigate forests? Where can we find them? How can we convey them into existing deserts? What about possible climate and soil quality changes? Could the pedology of soils support forest­like Biomass everywhere? Even if all this was possible, how can we be sure that top soil salinity would not rapidly increase and soil quality degenerate? What now is the Sahara desert, some thousand years ago was a forest. How can we expect to reverse such a long lasting natural desertification process of this magnitude?

Anyway, even if all this was possible, how can we expect that our intensive forest cultivation could keep pace with entropy degradation of solar system? The above estimates are for intensive forest cultivation with possible danger for the ecosystem. If we had to contain our exploitation to 1/100 or 1/10000, we should find 100 or 10000 Earth­like planets to cultivate nearby.

Let's make the hypothesis that long term Sustainability can be achieved only by setting aside the small share of fossil fuel that Earth produced in geological eras. A larger share may have endangered food chains and spoiled the system. At least, this is what we can understand if we consider the Earth as a self­regulating ecosystem that supports life forms for very long periods. No other example of long term Sustainability in systems of comparable complexity is available to us. This assumption relies on the engineering skill and wisdom of Nature as an unconscious designer. Excellent supporting evidence of this skill is the comparison of our aeronautic jewels with some flies that can stay perfectly still in turbulent air to sling off in any direction with shot­like acceleration. Furthermore, this assumption is consistent with the hypothesis of Gaia: Earth is a whole unique long lasting living organism. Anyway, this is the only assumption that can supply us with experimental evidence of something similar to complex long­lasting dynamic oscillating mutualism.

If this is the prospect, the idea of mutualism would require a (bio)technology 10⁵÷10⁶ times more efficient than the presently available natural one to pump solar energy (negentropy) into a system that now ephemerally sustains 5.5 billion humans. Besides, that should be achieved without interfering with current solar energy absorption.

Most of the solar radiation reaching the planet is now invested in natural cycles: to move huge masses of air and water in the atmospheric and ocean system, to feed the complex long lasting food chains in the sea system, to feed other complex long lasting food chains through the vegetal system on the ground. We cannot rely on technological energy collecting miracles, when and where solar energy is not already efficiently captured by some natural device (like on the deserts or on top of the clouds), or where it cannot be easily available to humans (as in the thermal gradients of the seas, or in ocean currents, or in lightning). It is easier to convert matter into energy than to extract energy from lightning, even if lightning would be a very clean renewable energy source with interesting low entropy characteristics.

Unfortunately, solar energy comes to us as a very diffused very light rain, not in huge steep concentrated waterfalls. Besides, it already aliments complex food chains, and fertile lands are perhaps already scarce for the direct cultivation of food.

At present, the highest food production per area per time unit is obtained by intensive industrial agriculture and industrial fishing, both possible with consistent fossil fuel investment. These techniques are a heavy load on the ecosystem. Nevertheless, these sophisticated food extraction processes have not solved malnutrition and poverty problems. They have raised human population instead. Pre­industrial European agriculture may approximate the criteria of mutualism. However, it was an agriculture that supported a far less numerous population. Notwithstanding this, overpopulation became a problem for that food extraction pattern, and the unsustainable demographic pressure probably was one of the major causes of colonization.

I repeat that we cannot expect to grow many layers of Biomass over and over, without paying a price.

Thus there is reasonable doubt on the actual possibility of mutualism to substitute current use of fossil fuels and the contrary may very well happen. In fact, an increased efficiency in resource conversion may add to current fossil fuel use, with further increase in human population density.

Hence, the problem seems to be the number of humans in the ecosystem.

If we could cut down the world population to 1/30 (even better to 1/3000) of the current number, we would gain a longer period of non pathological parasitism, subtly similar to mutualism. In this sense you are right: that is a political problem. But there may be physical (or technical) side effects in the practicalities involved by the transition from 30 or 3000 to 1. How can one deal with them?

How can one explain a mutualism that grows within the dynamic interaction of biological individuals, without conflicts, predatory actions among the individuals, or predatory action on the environment?

Lichens are quoted as an example of mutualism. However, the risk of generalization is to build platonist ideas and then believe in their existence as embodied entities. Mutualism between abstract species fungus and abstract species alga that form the combined species lichen may be an interesting anthropomorphic metaphor. It may represent a static relationship between two abstract man made classes, resulting from a human process of categorisation . But it gives little information about the physical dynamics of the assumed relationship and about the way to get into that relationship if one wanted to.

Moreover: the mutualistic lichen Tom is not mutualistic with mutualistic lichen Dick in sharing the same stone. And even if lichens Tom and Dick were mutualistic, how could they be mutualistic with lichen Harry, which has no more room on that stone?

Unfortunately the devil is always in the details: metaphorical thinking and eco­ethical concerns not always cover the details.

If mutualism arises from conflicts, every situation can be looked at as a dynamic environmental mutualism of some kind: 5.5 billion humans now live in mutualistic relation with their current fossil fuel stock and food extraction pattern, and so they will do it for a period that will be shorter than the entropy degradation of the Sun. Why should it be less mutualistic to use fossil fuels in chemical reactions than to eat plants and perform comparable chemical reactions, if the cycle is a dynamic cycle with birth and extinction turn­over for the life span of the Sun's entropy degradation or less? Fossil fuels were stored exactly as a negentropy pumping activity controlled by the ecosystem. The cycle is only longer, and maybe an oscillating one. But what does that mean?

If one considers the whole Earth ecosystem over the period of entropy degradation of the Sun from a global point of view -- which seems what you do when you desire a long lasting more mutualistic relationship between humans and the Earth -- then any local behavior is mutualistic by definition, as long as the laws of thermodynamics hold. That would preempt mutualism of any meaning. Somebody though seems to be looking for a bit more, like some kind of near­eternity for humanity. Quite a step beyond simple compatibility with physics, in my opinion.

Any biologic organism seeks and builds its complexity within the limits of entropy degradation of the Sun and within other constraints. This is achieved through evolution that is through the modification of its structure at different levels, playing the 'struggle for life' game. But this does not have to go on for the entire duration of the Sun life. Species evolve and extinguish more quickly than the life of the Sun.

If we had to keep up with entropy degradation of the solar system, we would have had a better chance as simple atoms of carbon. The claim that we should keep up with entropy degradation of the solar system sounds more like a pledge 'to preserve the garden of Eden with man as its almost almighty gardener', rather than a scientific scheme. We may be just a transient turbulence in the solar system 'canister of gas'.

That's why we can live. That's why we die, lasting quite less than the duration of the Sun. That's why civilizations live and die. That's why the so called species live and die. All of them with a time schedule quite different from the entropy degradation of the Sun. Each one with a life­span considerably shorter than that of the Sun. We would probably keep up with the entropy degradation of the solar system only if we could evolve into lichens, or better into carbon atoms. And that's how the Second Law -- or, better, the notion of Entropy -- may play a major role in a more subtle way: trading complexity for duration.

Claims for Sustainability generally assume some kind of pure gratuity, some net loss in favor of the future. They never say, in a lay way, why should anyone let vital resources to a vague global future.

He who likes to speak of platonist entities, may call this politics as opposed to the physics of the canister of gas. Anyway, this does not obliterate other physical constraints on individual actions that may arise from that kind of political considerations. It may be true that living -- as biological individuals -- is nothing but a despicable political affair. But it is an affair that all biological individuals physically take care of, always in some conflict with their environs.

Here is another question. Let us assume that human population must decrease in number to set up a long term mutualistic relation with the Planet, as suggested above. Or, let us assume that inducing mutualism is a 'political' problem (in the sense that it implies degrees of freedom and choices within a set of physical constraints). Then the question is: can this mutualistic Leviathan be rationally designed by some of its subjects? Or may it just be one of the many possible emergencies of evolution dynamics, implying a deep biological evolution of humans, or even their extinction?

A mirror image of this problem is the way our brain operates. Can the complex brain behavior be 'designed' by some of its neurons? The behavior of the brain is the result of neuron operation. But it also results from the history of the interactions of all the neurons with themselves and with the environs, as well as from the phylogenetic evolution of the brain­body. Moreover, the behavior of the brain can be understood in terms of neuron operation by the same set of operating neurons, at least in principle. However, its behavior cannot be designed or predicted from the single neuron viewpoint, for deep and non trivial physical reasons. It cannot even be understood by that viewpoint.

We should always be critically alert on what we can know and how deep our knowledge can be. Be it the behavior of the brain or, even more inscrutable, the environment.

Let's get back to mutualism. Limits to resources may induce massive reduction in human population: for example, as a result of a mutualistic action paradigm. From the local viewpoint, this may mean fewer living chances for one's own offspring. Or it may mean one's own premature death, or the perceived threat of it. With that prospect, we can at least expect that some groups of humans will adopt alternative reactions. They will probably act in a different way respect to behaviors rationally designed from a global point of view. They may behave, by any available means, in a non­mutualistic way even if this may accelerate entropy degradation of the environs. Mutualistic supporters should oppose a non mutualistic approach to safeguard mutualism.

That is the typical way heterotrophs, and any biological organism, evolve and pump­in negentropy in the local environment. That is why biological organisms living in this corner of the universe (but perhaps any theoretically conceivable form of life) generally endure less than entropy degradation of their free energy source. As far as I can see, that is how the Second Law, or better the Entropy notion, affects their behaviour in a more complex and subtle way than simply acting on molecules of an isolated canister of gas. It may very well be that we can only hope to slow down for a little our extinction with weak 'slow catastrophe' Utopias.

The abstract and absolute statement that we must take care of future generations produces strange and dangerous paradoxes, if one takes it seriously in a world of physical constraints. For example, it could mean that many individuals of the present generation should die prematurely. On the contrary, if the statement is not absolute -- because we fix a time limit to the next third generation -- then we have no criteria to answer the question why 'the third generation' instead of the present or the twentieth one, and so on. These are the typical paradoxes we face when we take ethics as an absolute reference. There is no way to dodge the 'struggle for life', for elementary biophysical reasons. However, people are usually too busy to fight for their own survival, to take care of humanity and of future generations in an absolute general way. They can barely take care of their near offspring and friends. Thus the problem seldom becomes pathological.

Unfortunately, mutualism, like any other claim for Sustainability, is a platonist abstraction. Regrettably enough, now we know that platonist abstractions, although inspiring, do not perform as elegantly as they do in the hyperouranios, when faced with physical constraints (notably time, space and complexity), that is when they are drawn into history. In fact, Plato was very busy at theorizing how to deal with the government of the Republic, with all those barbarians outside and inside the boundaries of the polis.

The history of Christianity and of many religions as well, show us that a great folly is necessary for the foundation of strong Utopias, such as a generalized mutualism for the salvation of Earth. Christianity though was by far less ambitious: it dealt only with the salvation of those who believed, which were far more true sons of God than misbelievers and cats, or than those fishes that fed the crowd in the desert. Regrettably enough, absolute certainty of the differences between living beings is fading even among good Christians. A new incarnation may be here to come?

I am sorry, but Sustainability seems just like Paradise: everybody has no doubt that it really exists, even if nobody has ever seen it.

Are Ethics and Utopia some kind of information technology for groups of humans to force the flow of resources in their favor? Is that the ultimate, unconscious reason of their origin and persistence in history?

Best regards.

Bruno Caudana

May 24, 1996      [ Back to Main Page ]

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