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THE GAIA HYPOTHESIS
The moment of inspiration—the epiphany, one might say—came to English scientist James Lovelock one afternoon in September 1965. He was in California, working for NASA (the space agency), worrying about the composition of the atmosphere on Mars as opposed to that on Earth. The former is very different from the latter, the rich mixture within which we all live and that is so vital to our well-being. What could be the reason for the difference, or, more precisely, what could be the causes here that make our atmosphere a medium so far from the sterile equilibrium that we find on the Red Planet? "As Pasteur and others have said, 'Chance favours the prepared mind.' My mind was well prepared emotionally and scientifically and it dawned on me that somehow life was regulating climate as well as chemistry. Suddenly the image of the Earth as a living organism able to regulate its temperature and chemistry at a comfortable steady state emerged in my mind. At such moments, there is no time or place for such niceties as the qualification 'of course it is not alive—it merely behaves as if it were'" (Lovelock 2000, 253–54).
Lovelock tells a good and polished story. Was it actually this road-to-Damascus experience? There was an insight, although whether he had the full conception all at once is a little hazy. Perhaps it had to develop and mature. What is clear is that when he was back home in England, he was ready to start sharing his convictions—"I was already beginning to look on the Earth as an organism, or if not an organism, as a self-regulating system" (JL). A crucial influence was none other than William Golding, author of Lord of the Flies and, in 1983, winner of the Nobel Prize for literature. He and Lovelock were neighbors in a small village and good friends. "When I first discussed it with Bill Golding, we went into it in considerable depth" (JL). The novelist was entranced by the idea; in fact, it was Golding who came up with the name Gaia, the Greek goddess of Earth. Yet, things did not really start to catch fire until Lovelock met and began collaboration with the American scientist Lynn Margulis. Apparently they first met at a meeting in 1968, but it was not until 1970 that they struck up a serious correspondence on the subject. They got together and started collaborating sometime toward the end of 1971. But me no buts. Earth is alive. It is an organism, it really is!
Who is Jim Lovelock, and who was Lynn Margulis (1938–2011)? Above all, in the circles of serious science, they are highly respected for their positive achievements (Turney 2003). He is a Fellow of the Royal Society of London, and she was a member of the (American) National Academy of Sciences, and no one begrudges them these honors. What I have to say in this book becomes a lot less interesting if one does not keep this fact firmly in mind. Lovelock (2000) tells us that he was born to a lower-middle-class family in England, just after the First World War, in 1919. (He claims to be the result of incautious celebration on Armistice Night, November 11, 1918!) He went to grammar school (the stream of publicly financed English secondary education reserved for bright pupils), and then, after a year or two of working for an industrial chemist, he got his undergraduate degree in chemistry. During the Second World War, he went to work for the government on practical issues such as the spread of the germs for the common cold—no small matter for bomber crews flying at high altitudes and wearing oxygen masks.
This was the beginning of twenty years of work on and around the boundaries of medicine and related areas of interest and importance. In retrospect, some of Lovelock's work seems to verge on the bizarre. For instance, he developed the technique for freezing and then resuscitating small mammals (a major concern for those wanting to preserve blood and other body parts). It became apparent early on that Lovelock had a real genius—and I use this term literally and deliberately—for instrument making: he was often able to make incredibly sensitive machines from war surplus and similar collections of junk. This did not come out of nowhere. From his earliest childhood, Lovelock was obsessed with science—he read and reread the science-fiction stories of the great writers, such as Jules Verne and H. G. Wells—but it was always science of a practical turn, the science of machinery. He would haunt the Science Museum (in South Kensington), awed and fascinated by the wonderful contraptions—steam engines, pumps, and the like, the life blood of the Industrial Revolution. The possibility of making and playing with machines drove him forward. His tendency to be somewhat of a loner—"I'm a little bit of an individualistic person" (BL)—led to his hobby becoming an obsession. By his own admission, referring to a sensible, all-weather coat that has become for the British a symbol of the socially inept, interest-absorbed outsider (e.g., train spotters), Lovelock became an "anorak of the first order" (BL).
What rescued him from obscurity was a warm and embracing personality, along with increasing recognition by others that his skills were leading to highly desirable products. The self-described "nerd" became a swan. Lovelock's most brilliant invention was a mechanism for detecting chemicals at infinitesimally small levels. The electron capture detector (ECD) is so precise that, to use Lovelock's example, it can record in Britain within a week or two the effects of emptying a bottle of solvent on a cloth in Japan. A man with such talents naturally attracted attention. He and his family spent several years in the United States while he worked at universities, and he found willing sponsors in both government agencies and private industry. So successful was Lovelock that he was able to quit his formal job and do freelance work, depending on his ability to produce things for organizations that needed his products and could pay well. Lovelock prides himself on this independence and frequently speaks scathingly of university hierarchies and (even more so) of granting agencies. Just as one suspects that there are many atheistic scientists who thank God for the Galileo affair, something they cite as proof of the awful nature of organized religion, so one suspects that Lovelock likewise thanks God for the foolish referee who derided one of his grant applications on the grounds that what he proposed was impossible. Like all sensible grant applicants, Lovelock had done enough of the work that he was already able to do the supposedly impossible—a fact that he still, some forty years later, reiterates with glee in almost every conversation. Something he is a little more reticent about—given that he was raised a Quaker and declared himself as a conscientious objector at the beginning of the Second World War—is the fact that defense establishments have gladly provided significant and regular funding for his production of sensitive instruments of detection.
Lovelock is not just a very clever scientist, he is an interesting man, with numerous fertile ideas and (as we shall see) a real talent for communicating with both general readers and specialists. He prides himself on his ability to move across boundaries: "I'm somewhat of a polymath. I feel at home in all branches of science" (BL). He was not fazed by those who thought it was daring, perhaps presumptuous, of an industrial chemist to propose a massive hypothesis about the nature of the whole planet on which we live. Although we shall learn later about the fundamental differences between the two Gaia enthusiasts, much that is true of Lovelock—especially his determination to push ideas because he thought them right rather than fashionable—applies as well to Lynn Margulis (Brockman 1995; Margulis and Sagan 1997). Twenty years younger than Lovelock, she was born and raised in Chicago, attending the University of Chicago at a ridiculously young age (fourteen), where she enrolled in the Great Books program. The heart of this educational program is working through uncut versions of the great classics of the West, such as Plato's Republic and Dante's Inferno, and her experience was surely a major factor in her refusal to be cowed by any authority or naysayer. She had learned to tackle head on the greatest minds of our civilization, and lesser mortals held no terrors. At nineteen, she married the man who was to become the best-known scientist in America, Carl Sagan, then an up-and-coming astronomer. She followed him first to Wisconsin (Madison) and then to the Berkeley campus of the University of California. Although she had two children and raised them pretty much unaided (the union with Sagan soon unraveled and then broke), Margulis enrolled in biology programs at both Wisconsin and Berkeley. Her first job after completing her PhD was at Boston University, where she stayed for many years before moving to the University of Massachusetts at Amherst to work in the Department of Geosciences.
In 1967, Lynn Sagan (as she was then) published in the Journal of Theoretical Biology a paper that had been rejected fifteen times. In "On the Origin of Mitosing Eukaryotic Cells" she argued that eukaryotic cells, that is, the complex cells with nuclei enclosing the chromosomes that carry (most of) an organism's genes (today understood to be lengthy molecules of ribonucleic acid), did not form de novo but are the results of symbiosis between more primitive cells, the prokaryotes (which have no nuclei and hence have the genes riding free). In particular, Margulis argued that some of the cell parts (organelles) of the eukaryotes, specifically including the mitochondria (the power plants that supply energy) and the plastids (particularly the chloroplasts that perform photosynthesis in plants), started life as free-existing, independent prokaryotes that were engulfed by other prokaryotes and (rather than dissolving) kept their own integrity and from then on contributed to the whole, that is, to the prokaryotes (now on their way to becoming eukaryotes) that incorporated them. Margulis (to use the name of her second husband, by which she was later known, even though that union also came to an end) was not the first to endorse "endosymbiotic theory," but at the time she published, it was ridiculed as unnecessary and improbable. Nothing if not persistent, Margulis followed her paper in 1970 with a detailed, book-length treatment of the topic (The Origin of Eukaryotic Cells), and slowly but surely the tide of opinion started to swing her way. The definitive evidence came in the 1980s, when gene sequencing had reached the level of sophistication that allowed comparisons between the nucleic acids found in organelles and those of various, promising, free-standing prokaryotes. The pertinent molecules were found to be virtually identical. Margulis was vindicated.
This was not to be the last time that neither praise nor condemnation could sway Lynn Margulis regarding a topic about which she had made up her mind. Her career was marked by controversies and the taking of unpopular positions. Like Jim Lovelock, she did not hesitate to take her case (or cases) to the public, and she wrote a number of books (several coauthored with her son, Dorion Sagan) that were specifically directed to the nonspecialist. With regard to the Gaia hypothesis, this determination and the ability to switch levels of discourse were important for both Lovelock and Margulis. Although it is true that back in 1970 Margulis had not yet gained the full respect of the scientific community, Lovelock was well known, and hence the collaborators expected that their ideas would be received at least respectfully, if critically. However, from the first they had trouble even publishing in professional journals. They were invited to a distinguished scientific conference to talk on the topic, but found, to their chagrin, that they "were not there as serious scientists but more as entertainment" (Lovelock 2000, 262). Fellow scientists did not want to discuss the ideas. They rejected Gaia "with that same certainty that the religious have when they reject the views of a rational atheist. They could not prove us wrong but they were sure in their hearts that we were" (263).
This did lead to what one might describe as a "teaser," for on the basis of his after-dinner talk, Lovelock published a short letter to the editor on Gaia in the journal Atmospheric Environment; but it was more a staking of claim than a detailed exposition and defense of the idea (Lovelock 1972). Fortunately, Lovelock and Margulis were not without resources. By the 1970s, old marital wounds had healed somewhat, and the encouragement and support of Carl Sagan was invaluable. He was the editor of the journal Icarus, and it was here that—after a rejection by Science (Clarke 2012)—the Gaia hypothesis got its first prominent outing, and it is to this hypothesis that we now turn. Bear in mind that here and throughout the book I use the term Gaia to mean Lovelock's hypothesis; I use different words for the ideas of others, however close they are to Lovelock's. In this chapter my focus is on the basic early claims and reactions. There have been changes that are important for our overall discussion, but addressing them must be deferred.
WHAT IS GAIA, AND WHY IS IT NECESSARY?
Start with an indubitable but truly amazing fact. Since the formation of our solar system more than four billion years ago, because of the way in which the sun burns itself up, the energy it emits has been increasing over time. And not by some trivial amount. There could well have been a threefold increase over the years since the system began. Yet the surface temperature on Earth has remained almost constant, varying at most within a 10° Celsius band around today's mean (fig. 1). That this is just chance, given that the existent temperature is just about perfect for terrestrial surface life, is simply "unbelievable." Natural theologians of course would invoke the deity, but for scientists this is not an option. A naturalistic clue surely lies in the fact that, compared to that of other planets, Earth's atmosphere is different—very different. It stands out in all sorts of ways—with respect to its acidity, its composition, its temperature (after discounting differences stemming from distances from the sun), and much more. Moreover, there is solid evidence that this anomalous atmosphere is not something new. It has persisted over vast geological time periods. But how and why? Lovelock and Margulis opened their discussion by going straight to the heart of the matter. Using the term homeostasis, meaning "balance" or "equilibrium," they wrote, "We believe that these properties of the terrestrial atmosphere are evidence for homeostasis on a planetary scale." And just as the stability is essential for the well-being of organisms, so they postulated that these organisms themselves play a positive role in maintaining the stability. Bluntly, they stated that the "purpose of this paper is to develop the concept that the earth's atmosphere is actively maintained and regulated by life on the surface, that is, by the biosphere" (Margulis and Lovelock 1974, 471).
There is nothing like a good name to get a good idea off to a good start, so, having noted that the ancient Greeks used the term Gaia to refer to the "great communal being" made up of "all creatures on the earth, animals and plants, including man," Lovelock and Margulis clothed themselves in the veneration of antiquity by saying that "in deference to the ancient Greek tradition," they would "refer to the controlled atmosphere-biosphere as 'Gaia'" (Margulis and Lovelock 1974, 471). And so one asks: What work is Gaia (or, in the authors' words, the "Gaia hypothesis") going to do? We start (as did Lovelock when he started thinking on the subject) with the atmosphere. Venus has massive amounts of carbon dioxide, comparatively little nitrogen, and no oxygen at all. Mars has little carbon dioxide and virtually no nitrogen or oxygen. Earth, as is well known, has about 20% oxygen, 80% nitrogen, and traces of carbon dioxide. What's going on here? If you considered only the inorganic world, you would make no progress. However, things start to change when you factor in life on Earth, the biota. Using the term cybernetics for the study of systems where feedback mechanisms—meaning by feedback cases where the end product (the effect) swings around and affects the initial input (the cause) and thus controls or regulates the working of the whole—Earth is just such a system. We find a number of feedback mechanisms, such as we find in the control of a room's temperature by a thermostat and, even more pertinently, in the human body's regulation of its temperature through sweating and shivering. Indeed, the authors wrote, "We suspect that the earth's control systems follow a similar complex pattern more comparable to the temperature control in individual organisms than to man-made models" (474).
Excerpted from the GAIA hypothesis by MICHAEL RUSE. Copyright © 2013 The University of Chicago. Excerpted by permission of THE UNIVERSITY OF CHICAGO PRESS.
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