Notes on Gaian Theology (II). The Return of the Goddess

This is what happens when you tell Bing to mix Gaia and Van Gogh.

The beauty of Gaian theology is that, unlike ordinary theology, you don't have to rely only on second-hand reports about the subject of your studies. Gaia exists, and you can perceive Her all around us. Then, the question is: what or who is She? 

As you know, James Lovelock and Lynn Margulis developed the modern idea of Gaia as a denizen of the Earth's ecosphere in the 1970s. Since then, it has evolved in various versions and has been misunderstood in various ways. For instance, Toby Tyrrell wrote a whole book trying to demonstrate that there is no such thing as "Gaia." He succeeded only in showing that one can write an entire book on something he doesn't understand at all.

But some ways of understanding Gaia are indeed untenable in light of what we know about biology. Sometimes, we hear of Gaia described as a "superorganism" and sometimes as engaged in optimizing the ecosystem for living beings. That's no good, as explained, for instance, in a 2003 text by Victor Gorshkov and Anastassia Makarieva, where they correctly note that if Gaia is supposed to be a superorganism, then She cannot exist.

But, one moment. Who said that Gaia is a superorganism? Besides, what is a superorganism? The term is sufficiently vague that it can be badly misused and misunderstood. In general, it is intended as any assemblage of biological subunits that don't individually reproduce but rely on specialized organs for that. A eukaryotic cell is a superorganism, just like an ant colony. And if you, dear reader, are a human being, then you are a superorganism, too. But that doesn't mean Gaia is one. For instance, I have Lovelock's 1988 book, "The Ages of Gaia," in my hands right now, and I can't find the term "superorganism" anywhere that refers to Gaia.

Instead, Lovelock described how he saw Gaia with his "Daisyworld" model, a highly simplified ecosystem consisting of daisies that can be black or white. Note that daisies are described as a single species, exhibiting a certain polymorphism in their pigmentation (humans have the same characteristic). Nevertheless, in the basic version of the model, there are no gray daisies, only black or white. That creates a certain degree of confusion, but even if gray daisies are considered, the results of the model do not change.

The Gaian mechanism in Daisyworld consists of the daisies slightly modifying the frequency of one of their alleles - the white pigment allele becoming more frequent- to cope with a gradual increase in solar irradiation. They do that to maintain their optimal temperature, but that also affects the environment. With more white daisies, the albedo of the planet increases, more sunlight is reflected into space, and the planet cools down. This is rare in the real ecosystem, but some algae may use this strategy. (image from gingerboot.com)

The daisyworld model is a brilliant idea, but suffers from a lot of problems: it has been described as being a toy, irrelevant to the real world, or simply meaningless. But if you see it as a “level zero” model, then it has a fundamental characteristic: the daisies of Daisyworld are NOT a superorganism.

The daisies have nothing of the complex structure of subunits that make a superorganism. They are just a population of loosely coupled individuals. In this case, they act on the environment by slightly modifying their genome; Lovelock had in mind a timescale of millions of years, so there was plenty of time for the genome to change. But that's not a necessary condition, on a shorter time scale we don't need to touch the genome to kick-start the Gaian mechanism. Here is how Gorshkov and Makarieva describe the concept they call "biotic regulation."

Let us suppose that the living objects capable of environmental control are trees, while the regulated global environmental characteristic is atmospheric carbon dioxide concentration. Suppose further that in the course of a major atmospheric disturbance (volcanic eruption, anthropogenic activities) the global atmospheric carbon dioxide concentration becomes significantly higher than the biotic optimum. All trees on the tree-covered planet are thus faced with approximately equal unfavourable environmental conditions. Normal trees immediately begin to work on removing the excessive carbon from the atmosphere in order to restore the optimum concentration of carbon dioxide. This can be done, for example, by depositing the excessive atmospheric carbon in organic form in soil and sediments.

A different Gaian mechanism may not involve the biosphere alone, but the whole ecosystem is formed of the linked geosphere, atmosphere, and biosphere. It is the case of the geological carbon cycle that seems to have been fundamental in keeping the Earth's temperature approximately constant over a time scale of hundreds of millions of years, as I described in a previous post.

None of these mechanisms imply centralized control, altruism, intelligence, planning, or things like that - no superorganism whatsoever. Gaia is an emergent property of the ecosystem that results from internal feedbacks that tend to keep the system in a homeostatic condition. She is the result of the typical “win-win” mechanism of holobionts. Every element of a holobiont acts for its own advantage, but the system is organized in such a way that the individual advantage works also for the advantage of the whole holobiont. This point has been discussed in detail by Zu Castell, Lüttge and Matyssek in a 2019 paper, where they say

Summarizing, Gaia is represented by the set of interactions of the communities of living organisms, the ecosystems they create and the modulation of environmental processes they generate, as well as the buffers they maintain. All of them comprise an infotype of interactions which develops and adapts. Such an integrative view of evolution (Noble 2017) has no privileged level of causation (Noble 2012). But as an observer, we perceive the set as a self-regulatory system leading to unexpected stability over eons.

And if some element starts tricking? The holobiont is at a disadvantage with respect to other, more efficient, holobionts, and it is replaced by them. The basic element of Darwinian evolution is not the organism, but the holobiont. Zu-Castell and co-authors note:

But how about theology? Is Gaia a Goddess? In a certain sense, yes, but we’ll see that more in detail in the next post.

(h/t Anastassia Makarieva)