You probably have a good intuition about what sustainability is. However, it can be difficult to apply this intuition in practice. Imagine you are a product designer, or responsible for choosing the assortment of a supermarket chain, or simply a consumer: which of these two dishwashing brushes is more sustainable?
What do sustainable dishwashing brushes look like? You can probably only guess. Wood must be harvested (from where?), metal is mined, the other brush is made from fossil oil. And what happens when the brushes wear out?
This blog does not give you concrete solutions, but it gives you background thinking and general categories that you may apply yourself when you need to decide how to achieve sustainable practice in your own circle of influence.
To know better about sustainability, I think it is necessary to look at how nature works fundamentally and on a material level [1]. Let’s start with the first observation:
The biosphere only thrives because it is far from a state of equilibrium: the earth is constantly fuelled by intense solar radiation.
Even a short downturn in this fuelling (caused by a large meteorite impact and possibly volcanic eruption) led to the extinction of the dinosaurs. However, heat or warmth alone do not make life. Crucial to life is that energy is extracted from sunlight specifically to create the beautiful structures around us that we see (and eat). You can grasp this with a very early example from the history of life: About 2.5 billion years ago, cyanobacteria began to proliferate because they could effectively extract energy from sunlight using photosynthesis (but photosynthesis probably existed already before [2,3]). Concretely, cyanobacteria used the energy of sunlight to excite an electron in water so that the water could bind with CO2 to form the building block (CH2O) of sugar, starch, cellulose and a host of other substances [4], as shown here at the atomic level:
This figure is a highly simplified version of actual photosynthesis, as it only shows the net flow of substances. However, this viualizes how the cyanobacteria took CO2 from the atmosphere and released oxygen. Back then, the atmosphere contained hardly any oxygen, and more than that, the new oxygen killed much of the other early life. You can call the oxygen the waste of the cyanobacteria or – at that time – highly toxic waste. Physicists call it value-free:
Dispersion
You may know this word from heat, for example in your coffee cup: it is dispersed into the surroundings when your coffee cools down. Dispersion can include not only heat, but also substances such as the oxygen produced by cyanobacteria, or for example the spread of plants or the meandering of rivers. You will soon see that dispersion is fundamental when it comes to sustainability. That’s why I’d like to give you a good sense of dispersion by the end of this blog article, without going into the physics. Just bear with me.
Now back to the cyanobacteria frolicking. They are an example of a general observation that:
No mechanism has been found that prevents nature from producing waste and its consequences, even if the waste kills almost everything else or the host that produces it.
Indeed, yeast bacteria are killed when their own waste (alcohol) accumulates to the level you can read on wine bottles. Why does nature do this? A fundamental law of physics [5] states that structures can only be built by using energy and creating dispersion. For fundamental reasons, there is no other way to build structures [6]. Therefore, any mechanism that prevents nature from creating waste would also prevent nature from building structures.
For example, if you are tidying up your living area, you must move around, pick things up, and you will feel warm afterwards. You build a structure from something less structured and produce a certain amount of heat that you disperse into your surroundings. On a planetary scale, imagine that the energy in sunlight sets off a cascade of structure building and dispersion throughout the earth system [7] [8]. The sun’s heat causes winds that form clouds but dissipate heat from the tropics to the temperate regions [9], the clouds rain down on us causing masses of water that form meandering rivers [10][11] that form niches for plant communities to disperse themselves, to be eaten by herbivores [12], to be eaten by carnivores… This is structure building and its dispersion of energy and materials in myriad ways. The dispersed energy eventually leaves the earth as thermal radiation (infrared radiation) into the sky, hence the temperature on earth is quite stable even though it is constantly irradiated by the sun [13].
Now there is another aspect of dispersal: the cyanobacteria did not use the oxygen they dispersed, oxygen simply accumulated in the atmosphere, as this graph shows [14][15] (the extended ranges present uncertainties in tracing back the exact amount of oxygen):
This is an example of the general observation that:
Nature rarely recycles. It mostly dumps what it no longer needs.
Some animals, like some female spiders and female praying mantises, may actually eat their mate after mating to use his proteins for egg production. But more often: a tiger disintegrates to soil, not to a new tiger [16] [17]. And peat bogs don’t even do that. Their acidic environment even prevents the decomposition of dead plants and animals, so that carbon accumulates under the peat, which means that peatlands store more carbon than forests [18]:
And we urgently need to restore those peatlands that are used for agriculture, to prevent this carbon stock from escaping back into the atmosphere as CO2. After all, the moderate temperatures on earth are only possible because a lot of carbon was dumped, meaning that photosynthesis has taken CO2 from the atmosphere to build life forms, which in turn has not been recycled back to CO2 but buried, leading not only to subsoil but also deeper deposits like coal, natural gas and fossil oil. It may surprise you: burning fossil fuels means recycling what nature has dumped. Take this in.
This also means:
Only a part of what nature dumps is available for other use.
After the cyanobacteria started producing huge amounts of oxygen, it took about half a billion years for other life forms to recover from this toxic waste. New life forms emerged that used oxygen for their metabolism, just as we humans do when we breathe. Oxygen metabolism is stronger than so-called anaerobic metabolism and led to multicellular life flourishing, making larger life forms possible, as you can see in the lower half of the oxygen graph.
With this, the energy demand of life has increased since then. Do you believe that nature only uses the energy and resources it needs? Let’s look at an event that took place 49 million years ago [19]. At that time, the atmosphere contained more CO2 than it does today, so the northern polar region was warm and humid and did not freeze in winter [20]. A fern called Azolla thrived to such an extent that the bottom water no longer contained oxygen, so dead Azolla that had sunk to the bottom were preserved in a similar way to bogs [21][22]. If you drill through the sediments of that time today, you will find a layer of compressed Azolla remains almost 20 metres thick [19]. The fern thrived so much that the CO2 content in the atmosphere decreased significantly over a period of about a million years, as did the temperature [23]. This and many other examples show that:
Nature shows no self-control when resources are available.
Nature uses as much energy and resources as it can until the scarcest resource starts to become limited. This is called Liebig’s law of the minimum [24]. In physics, this makes sense. Since the earth is not in a state of equilibrium, dispersion is maximised [25], and thus energy consumption is normally maximised as well. Only if we were in a closed system and close to equilibrium would optimisation dominate, dispersion minimised and energy consumption minimised [8].
Thinking about optimisation: there are numerous examples of seemingly optimised creatures, like dolphins swim with incredibly low resistance, birds seem to have optimised flight behaviour, and even the walking of us humans seems to be optimal for the conservation of energy. However, measurements of dolphin movements [26] show that there is still room for improvement, and seagulls do not fly optimally either [27], and our gait is not optimised either [28] – robots [29] can do better… From an evolutionary point of view, this makes sense. Natural variation (a form of dispersion) leads to selection and thus only to sufficient body structures and behaviours, not optimal ones.
Another aspect of dispersal maximisation emerges when answering the following question about sustainability: Why do so many different plant species grow on undisturbed land, and why is their population so stable? If a single plant species had only a tiny advantage in propagation, it would multiply faster and –sooner or later – dominate completely. It can’t be that all the plants in this population have exactly the same reproductive capacity, can it?
One answer is that different plant species have different root and foliage requirements, different flowering and fruiting times, which results in them occupying different “niches”. And in most plant species, each individual is slightly different from the others (just like us humans), and plants spread over wide areas where environmental influences also vary [30][31]. In this diverse mix, plant species compete with others not just in one way, but in many ways – in fact, many, many ways. The more diverse these aspects are, the smaller the competitive advantage of one species over all the others. This is in physics again: dispersion [32].
In a vegetable patch or in monocultures, dispersal is kept to a minimum, which means that the “desirable” species are constantly invaded by the spread of “undesirable” species – without end, because dispersal is maximised by fundamental laws. The only way to effectively prevent the invasion of “undesirable” species in highly non-dispersed land is to kill the “undesirable” species in the entire environment. Part of monoculture farming is about to do just that [33] and in this blog article I tell more about this.
I hope I have given you an understanding or intuition of dispersion. Less appealing to you, perhaps, are the consequences of dispersion:
You probably thought that nature recycles everything and finds a use for everything, that nature adapts optimally, that it uses only the energy and resources it needs, and that it is a closed system in equilibrium… But because of dispersion, nature produces waste, it seldom recycles but dumps what is not needed and makes only a part of it available for other use, it seldom optimises but often maximises, and has no self-control, whatsoever, over its resource consumption [34][35].
We humans are indeed like that too… we are on our way to reach planetary boundaries [36] in a natural way. We are part of nature!
This challenges the frequently voiced statement that we have exempted ourselves from nature. Indeed, after reading this blog, you may wonder: if – instead of following nature – should we behave differently from nature to integrate ourselves more gently into nature?
Before jumping to conclusions, let’s first consider different ways of looking at sustainability in the next blog.
I hope you enjoy thinking about sustainability while you do your dishes. Take a look at your brush and
have fun
Pietro
P S. Or you may do the opposite: I invite you to write in the comments what kind of slogans you may use to promote environmentally damaging products such as coal-fired power plants, using the insights from this blog article, like: Burning fossil fuels means recycling what nature has dumped. When you write catchy slogans like this, surprising solutions to sustainability can emerge. If so, please include them in your commentary.
Acknowledgements
This blog article was partly inspired by K. R. Skene, Ref. [34], although I don’t agree with all his statements and implications.
The photo of the dishwashing brushes was taken by the author.
For calculating the molecular structure in the graph on photosynthesis, I used the free software Ascalaph from Agile Molecular, Stockholm, Sweden, by Vladimir Eskin. http://www.biomolecular-modeling.com/Ascalaph/index.html. I used the CPK space-filling model to emphasise the molecular shapes.
References
[1] In physics, this approach is called thermodynamics. It is the most principled method of assessing the impact of one system on another and therefore applies to all living organisms and the economy. In this blog post we will not go deeper into physics, I just want to say that this blog is based on a physical understanding of the underlying processes.
[2] T. Oliver, P. Sánchez-Baracaldo, A. W. Larkum, A. W. Rutherford, and T. Cardona, “Time-resolved comparative molecular evolution of oxygenic photosynthesis,” Biochimica et Biophysica Acta (BBA) – Bioenergetics 1862 (2021). https://doi.org/10.1016/j.bbabio.2021.148400
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[4] Ascalaph, molecular modeling software by Vladimir Eskin, http://www.biomolecular-modeling.com/Ascalaph/Ascalaph_Designer.html, https://sourceforge.net/projects/asc-designer/
[5] Structures can only be transformed into other structures without dissipation if it is possible to remain in thermal equilibrium, e.g. if the new structure is not more strongly structured than the old one, and if the transformation proceeds slowly.
[6] This is the second law of thermodynamics, formulated as entropy, a measure for dispersion.
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[13] This is so with the exception of rising greenhouse gas concentrations, which weaken the flow of dispersed energy into space, leading to further dispersion on earth, such as the jet streams (high-altitude winds) that began to meander. This caused for example a cold spell in Texas and later a heat wave and drought in California, Canada and the Mediterranean.
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[33] Secretariat of the Convention on Biological Diversity, “Global Biodiversity Outlook 5” (2020).https://www.cbd.int/gbo5
[34] K. R. Skene, “Sustainability policy and practice: Is Nature an appropriate mentor?,” Environment, Development and Sustainability (2021). https://doi.org/10.1007/s10668-021-01432-x
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[39] J. E. Nichols, D. M. Peteet, “Rapid expansion of northern peatlands and doubled estimate of carbon storage,“ Nat. Geosci. 12, 917–921 (2019). https://doi.org/10.1038/s41561-019-0454-z
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