Commentary: Dorion Sagan - James Lovelock, Gaia, and the Remembering of Biological Being


James Lovelock, Gaia, and the Remembering of Biological Being
Dorion Sagan


The occasion of the passing of James Lovelock (1919–2022) provides us the luxury of attempting to look back on the life, not only of a great scientist, but of the major object of his intellectual attention, the life of the biosphere, whose status as (to quote David Bowie) a space oddity, he discovered. The Gaia hypothesis was a response to the search for extraterrestrial life, specifically NASA’s Viking mission of robotic landers to see if there were life on Mars. Self-described as an engineer and inventor more than a scientist, Lovelock invented the electron capture device, an extremely sensitive chemical detector which found human-made industrial products, such as DDT and PCB toxins in remote regions of Earth, helping to spur Rachel Carson’s cri de cœur, which was the 1961 book Silent Spring, itself a spur for the environmental movement. Introduced by my father, Carl Sagan, with whom he shared an office at the NASA’s Jet Propulsion Laboratory in Pasadena, California to my mother, Lynn Margulis, who was interested in the composition of Earth’s early atmosphere, the two, Lovelock and Margulis, went on to develop Gaia theory, which explored how Earth’s biosphere, far from being a planet with some life on it, was a giant thermodynamic system away from chemical equilibrium.  Lovelock’s idea for detecting the presence of life in space—which, inverted, revealed that Earth had a living body, a kind of planetary physiology—depended on his studies which showed and continued to show multiple chemicals in Earth’s atmosphere that existed in concentrations orders of magnitude out of chemical and thermodynamic equilibrium. But they were there. Methane, butyl mercaptan, many organic compounds should disappear in our atmosphere steeped in reactive oxygen (O2), they should react and disappear. But they don’t. Because, life put them there and continues to put them there, replenishing its reactive compounds.

But how? Who? Microbial ecologist Margulis pointed to the gene-trading bacteria, with their many forms of metabolism, metabolic virtuosi as she put it. They completed chemical cycles and produced the atmosphere, the oxygen-rich atmosphere with its redox gradient. The cyanobacteria, evolving to use the hydrogen in water (H2O) as a source of electrons for photosynthesis, released O2, loosing free radicals onto the world. Anaerobic life, primarily archaea, suffered and died, while some survived by taking refuge in the anoxic muds. Oxidized iron, Margulis pointed out, such as that from which the iron for cars in Ontario and Michigan is mined, show evidence for global oxidation some two billion years ago. Ozone (O3) also arose from the surfeit of water-using green life. The very planet’s blue color, Lovelock pointed out, was the result of the light-scattering properties of oxygen atoms loosed by energetically lustful life. The collaboration between the atmospheric chemist and the microbial ecologist, was especially fruitful. An example was Margulis’s identification of the source of the persistence of methane, which immediately reacts with oxygen to become carbon dioxide and water, in Earth’s atmosphere. It is produced by methanogens, considered methanogenic bacteria at the time, now usually classified as archaea. In termites and cows, helping to digest the refractory cellulose of wood and grass in anaerobic environments, symbiotic microbial communities produced methane, as did prokaryotes in seaside expanses called microbial mats. The metastable atmosphere of Earth was like part of the body, in this case inside-out with relative to mammals, with the circulatory system on the outside rather than the inside. Whereas Lovelock characterized Gaia as an organism, Margulis differed, pointing to the datum that no organism consumes its own material wastes. Gaia is better characterized as planetary life form—a body, yes, but subtler than an organism, it produces waste mostly as heat, the end product of metabolism that cannot be used by any living organisms. Like all lifelike and living cycling systems it produces entropy, in thermodynamics, a measure of the spread of energy.

That Carl Sagan, who was suspicious of the grand claims that Earth itself was alive, knew of Gaia is apparent from his first sole-authored book, Planetary Exploration (1970). In that book, based on his Condon lecture at Portland University on his ex-wife’s birthday, Sagan takes the reader on a thought experiment on how to detect life on other planets. If one approaches a planet relatively closely, one might notice life by the shadows of structures that would seem quite unlikely geologically (e.g., the stilt-like feet of animals). Even from further out the perspicacious observer could detect, say, the lights of cities at night, while from astronomic distances one might still be able to receive electromagnetic messages. But, Sagan says, without mentioning Gaia by name, the best evidence might be the unexpected presence of methane in an oxygen-rich atmosphere; the clearest message of life on Earth might be, he drily jokes, an unintended consequence of “bovine flatulence.”

Leaving aside that cows belch almost all their methane from the other end, the point is well taken. Gaia’s inside is our outside. “She” could be detected spectroscopically by extraterrestrials, say Martians, with our level of scientific chemical voyeurism. Alas, Mars’s atmosphere was found, prior to the landing of Viking’s robotic landers, to have an atmosphere almost completely of carbon dioxide, showing no obvious chemical signs of life, let alone a planetary surface steeped in it. Like many of science’s great discoveries, Gaia was not directly sought, or supported by funding agencies, but discovered serendipitously. In retrospect one might argue that Gaia, the notion that Earth is no more a rock with some life on it than you are a skeleton infested with cells, may be considered the most striking result of NASA space exploration, as well as SETI, the search for extraterrestrial intelligence. Life is an open thermodynamic system in space, transforming the solar gradient between Sun and space, primarily through the advanced, sensitive natural nanotechnics of water-using photosynthesis, into the redox potential of Earth’s highly energized, because continuously oxygen-supplied, biosphere. Lovelock with Margulis probably deserved a Nobel Prize in Physiology or Medicine for their work. More important, however, is the intellectual and affective sequelae of the scientific idea that our planet is a living body, of which we are in no way a key part. Lovelock’s thought experiment, that Mars did not harbor life because its atmosphere was in chemical and thermodynamic equilibrium, turns out to be right.

However, and although my Gaian matchmaker was not thinking directly of Lovelock when he said this, that aging British scientists tend to go a bit dotty in their later years, an argument can be made that Lovelock did not fully appreciate the consequences of the Gaia theory he helped spawn. (Carl Sagan said this to me in a conversation about a review of a book by Fred Hoyle, the astronomer who precisely predicted the means by which helium turns to carbon atoms inside stars, and who termed the term big bang, but believed life and the universe might both be eternal. Hoyle argued that bacteria and viruses existed throughout space, further suggesting that Mars’s rusty regolith might be the product of Pedobacterium, an iron-oxidizing bacterium, and that the odds of life evolving on the Earth, or at all, were incalculably small).

With his deep insight that the atmosphere is as highly organized and unexpected as a beehive or a sandcastle on the beach, Lovelock’s notion of planetary chemical disequilibrium as a way of detecting life on a planet, matured from a hypothesis of life regulating the planet’s atmospheric chemistry, to, with Margulis, a theory recognizing microbes as the main actors. The “bovine flatulence” that might alert aliens to life’s terrestrial presence is in fact from methanogens, archaea that have survived from the Archean Eon prior to the buildup of oxygen on the planet and iron and uranium oxides in the fossil record. As mentioned, Margulis differed from Lovelock in describing Earth life as an organism. But although the metaphorical matrix spurred by looking at life as an organism—later Lovelock would say that deforestation and industry are destroying Gaia’s “skin”—could be fruitful, it also overreached, for example, when Lovelock compared Earth to being an old lady on dialysis who needed human help, that is, geoengineering. Margulis told me that Lovelock excused such overreach by saying that if people thought of Earth as an organism, they would be less likely to destroy it. There was something of Mother Mary in it. But given the treatment of women in a patriarchal society—or even female-associated symbols, such as the secret Cold War Air Force Project A119 to detonate a nuclear device on the moon, of which my father was apprised—the Soviets had a similar plan—the notion seems doubtful. “Love your mother,” said my mother’s T-shirt, over an image of Earth from space, in a smiling photo of her from the 1970s. But Gaia is not a mother or an organism, but something stranger, an alien body, based on prokaryotes their symbioses and gene-trading, that we are just beginning to understand. His later works, playing with notions of planetary medicine and technological salvation, culminate in Novacene, where Lovelock suggests he knows that only Earth in the cosmos is alive. The comment is suggestive, even exemplary of, the general anthropocentrism that renders the aliens of Star Trek as humans, a self-centeredness which shows up too in the bloating of our individual fears of death into worries over the death of the planet.

The theory of Gaia is in a sense an autobiography of a planet, an autobiography told by very small part of the vast nexus of life, with its estimated thirty million species, not including the prokaryotes, which trade genes so often and don’t reproduce sexually so don’t conform to the traditional biological species concept, which like the rest of human knowledge must take into account the provinciality, the particularity of human observers. The genesis of Gaia was thermodynamic but its description by Lovelock was cybernetic. Certainly there are loops, feedbacks, responses by sensing living matter, which is not just reactive. The growth of algae and trees in the sun produces volatiles that not only signal in nonhuman chemical languages but also serve as nuclei for raindrops, making a loop between the growth of organisms under the sun and the production of clouds and rain blocking the sun’s light and adjusting the shutters, as it were, of life’s more than human home. Cybernetics was attractive at the time of the early development of Gaia because it linked the mind-like loops of sensing machines to the real minds, or awarenesses of organisms. In retrospect Lovelock and Andrew Watson’s Daisy World model, which showed in principle how colored daisies could cool a planet showered with increasing energy from its star (by, for example, white daisies growing and reflecting more light as the sun’s luminosity increased), can be said to have mimicked mind, fooling mechanist scientists—men that denied that planetary thermoregulation was possible without human-like intelligence or communication between organisms, or aeons of evolution by natural selection. Simple cybernetic feedback, modeling growth between a temperature range, which even some non-living thermodynamic systems can do, suffices in principle, without natural selection, to thermoregulate a planet. But cybernetic descriptions, linked with computers, ultimately became a sterile path. In Novacene, Lovelock, who once in Nature, in an article titled “Life Span of the Biosphere,” calculated that Gaia would end in secular biological hellfire when it ran out of carbon dioxide to counter the increasing luminosity of the sun, argues that AIs may be needed to calm Earth’s anthropic fever. But Hong Kong-based philosopher, Yuk Hui seems right to me when he says, in an interview with Anders Dunker, that “When we think of humans and the Earth as a cybernetic system, we have already lost the world” and then goes on to talk about Heidegger and the forgetting of being. The most cited scientist by Heidegger is Jakob Von Uexküll, who as a scientist shamanized himself into what it must feel like to be other organisms, including, famously, (as Deleuze and Guattari reprise) a tick. Heidegger famously argued that nonhuman animals are “poor in world.” But maybe not, maybe not at all. I would argue that every organism may have a world, a full world, an idios kosmos, as well as a koinos kosmos insofar as it interacts with members of its own and other kinds. (The terms are those of Greek philosopher Heraclitus, the first referring to our private worlds, as when we dream, the second, to the world we share). The thermodynamic dissipative spaces where living beings find their homes, necessarily using energy, taking in substrate, and producing wastes, encompass a feeling of being alive, if not freedom to move, act, and be. Other beings may have worlds as rich, and in some cases richer, than our own. In the 19th century Samuel Butler argued that microbes (our ancestors) far from being unfeeling automatons, have their own sensations and little purposes, and their own technics, “tool-kits” as he put it. Their activities, their technics, over hundreds of millions of years, created bodies. “We don’t remember,” Butler (whom Gregory Bateson described as “Darwin’s most able critic”) says, “when first we grew an eye.” Living being is rich, on Earth and perhaps elsewhere throughout the cosmos. Our present infatuation with technology may be terminal, but the present technological malaise may also be growing pains, as were, for example, the calcium ions that toxified Archaean marine protists, eukaryotic cells on the line to the ancestor of animals including us. The calcium ions in some cases were stockpiled extracellularly, jump starting the evolution of microscopic marine exoskeletons, which it is theorized may sometimes, after falling to the ocean floor, become subducted, greasing the skids of continental plates.

Unlike in human society, where particulate pollution, which blocks light at day, incrementally cooling, but more than makes up for it by increasing temperatures at night (when particles reradiate solar and Earth absorbed energy), profligately damaging waste is not a feature of the smoothly entropy-producing Gaian living nexus, about one-third the age of the universe dated from the Big Bang. (Indeed, our own bodies, insofar as we age, seem to show a kind of unconscious physiological wisdom, one that evolved in clades of organisms that tend to overgrow their environments, thus exposing them to mass die-offs via predation, starvation, and infection.) Gaia is more than cybernetic, it is autopoietic, self-producing, as are its constituent cellular members. We would do well to remember this biological being, which far transcends our computer models (although, as mentioned, even some of these may effectively pass a version of the Turing Test). Cybernetic thinking (even though IPCC models do not incorporate Gaian living feed backs into their supercomputer models) as an adequate description of the real biosphere is failing. We need to have more respect for the unknown, for the metabolically diverse microbial life from which Earth life comes, and from a small subsection of which we and our brains evolved, and in whose ecosystems, we are embedded.

When I asked Margulis how scientists can claim to predict the climate when I don’t even know how I’ll feel after eating lunch at a restaurant, she said “no one knows.” She also surmised that the major evidence for humankind remaining in the fossil record will be a very thin layer of iron, “from the cars.” A little humility is a good thing, whether on the question of life existing throughout the cosmos on untold planets, or its being confined to our pale blue dot, quickly becoming a pinpoint as we move away from our privileged realm. As the example of those toxic calcium ions that must be exported across cell membranes by marine eukaryotic cells suggests, we humans are not the first to make a mess of things. Elements necessary for life include cosmically common carbon, hydrogen, nitrogen, oxygen, phosphorus, and sulfur. Elements partly under Gaia’s planetary control include calcium, originally a toxin to marine eukaryotic cells, but eventually stockpiled outside multiple forms of algae as exoskeletons, such as those produced by Emiliania huxleyii in the English Channel, sometimes growing in blooms so large that they are visible by satellite as white submarine clouds. Their intricate skeletons look like Venetian blinds, and may be used accordingly, adjusting incoming levels of light. Gaian theorizers suggested that the gas dimethyl sulfide, released by the microbes, may serve as nuclei for the formation of raindrops, thus establishing a link between growth of massive blooms of plankton in the hot sun and subsequent cooling by clouds. Gaian control does not appear to have arisen from processes that are top-down, let alone ones involving nonliving computer chips. The multibillion-year complexity and ecological recycling of Gaia, the transition of calcium waste into bones and shells and skulls, of toxic O2 into a vibrant atmosphere, and so on, came about not through ape overseers but by countless individual actions, a billions-year reign of sensuous anarchies, a more-than-human ecological being maintained by countless autopoietic actions, intentional and not. Let us not forget our biological being.