Gaia and the Lovelock legacy

James Lovelock, whose birthday fell on July 26, proposed the compelling but controversial idea of Gaia. Sahastrarashmi offers an appreciation of the man and his work

Gaia as metaphor; Gaia as a catalyst for scientific enquiry; Gaia as literal truth; Gaia as Earth Goddess. Whoever she is, let’s keep her. If science cannot find room for the grand vision, if Gaia dare not speak her name in Nature, then shame on science. To recant now would be a terrible thing, Jim. Don’t do it.
- Fred Pearce

We looked at the Earth in our imagination, and therefore with fresh eyes, and found many things, including the radiation from the Earth of an infrared signal characteristic of the anomalous chemical composition of its atmosphere.  This unceasing song of life is audible to anyone with a receiver, even from outside the Solar System. 
- James Lovelock

In simple terms, the GAIA theory states that planetary environment is regulated, or is homeostatic, and if we consider the sum of all life on this planet, Gaia, we realize that it is this self-regulation that allows optimum conditions for life to exist. In other worlds, Life maintains the conditions that allow it to thrive over geological time. Some commentators have extrapolated from here that Earth is a living organism since like any (super) organism it exhibits physiological processes that keep it functioning. Lovelock has supported this view.

There is enough evidence for planetary self-regulatory cycles and, as scientists continue to explore and research them, the role of Life in some of these cycles has been established beyond doubt. In fact, the hunch that a planetary-level self-regulation could possibly exist on Earth came from looking at one of these processes – methane replenishment.

While at NASA, Lovelock was struck by the seemingly inert and stable equilibrium of gases on other planets. However, on Earth he observed that gases like methane occurred in quantities higher than otherwise physiologically possible. Methane reacts with oxygen and should ideally vanish, but its constant presence in the earth’s atmosphere meant that it was being produced constantly. Lynn Margulis later pointed out the origin of the gas as coming from living organisms like cattle  (through belching). Lovelock termed this as a dynamic equilibrium where the composition of such reactive gases was being maintained by their constant production by Life and this led him to the insight that perhaps Life was responsible for the continued habitable conditions on Earth. Looking at the dynamic composition of the Earth's atmosphere and the near-equilibrium atmosphere of other planets (in this case, Mars), Lovelock argued that there is no life on Mars, which NASA's probes later confirmed.

Gaia, according to Lovelock, maintains the temperature of the planet, the composition of gases and the alkalinity of oceans among other things.

For instance, Lovelock points out, the luminosity of the sun has gone up by almost 30 percent over the past 4.5 billion years (Earth’s age) but the surface of the earth has not heated up in proportion. This, Lovelock argues, is due to Gaian regulation that occurs due to the reduction in greenhouse gases over time and the maintenance of cloud cover (albedo). Similarly, oxygen is maintained at 21 percent. Anything more than 25 percent means that woods will catch fire, and less would threaten the existence of life. This composition is so well regulated that the volume of atmospheric oxygen has not varied by more than 5 percent from 21 percent for the past 200 million years.

Another interesting temperature regulation system is the Thermohaline system described by Tyler Volk. In his book, Gaia’s Body, he describes this convection cycle of cool and heavy salt-rich waters sinking down at the poles and then spreading through the oceans in a series of upwells, which then move towards the poles. This convection cycle that takes 1,000 years to complete one revolution. This, along with the winds that stir up due to equatorial heating and polar cooling set up a heat pump that normalizes the temperature extremes that would otherwise result. Volk calculates that without this “circulatory” system, the temperature at poles would be -90 degrees Celsius (instead of -23) and 60 degrees instead of 26 at the tropics. A very inhospitable planet!

Gaia hypotheses came under strong attack from Neo-Darwinists, climatologists and geologists. So strong was this attack that Lovelock likened it to a cold-water dip – an absolute shock to the body but accompanied by a clearing of the head. Evolutionary biologists attacked it for its teleological nature – it suggested that the organisms and the environment had somehow conspired to create this regulated system. This is an impossible task for organisms to accomplish since they are locked in their struggle to survive; these selfish individuals operate at the level of their immediate environments. They cannot possibly take actions that benefit the planet overall while entailing a cost to them (thereby loading the cost-benefit equation against their survival). Dawkins pointed out that the Earth cannot be an organism (hence self-regulatory), since it did not evolve out of natural selection as species do.
The attack was more scathing since Gaia and the idea of Mother Earth resonated with new-age mystics, environmentalists, etc. who found the romantic idea of a living Earth emotionally enriching. The scientific community condemned this takeover and the resultant mystic overtones in popular culture. Moreover, the idea of a living Earth recalled animist traditions which post-Descartes science was loath to be associated with. At a deeper level, the phenomenon of planetary regulation is seen as emergent phenomena by Gaian scientists, where higher-level phenomena cannot necessarily be broken down to parts and explained entirely on that basis. This runs against the grain of reductionist science. Underscoring this point Margulis wrote: “The sum of planetary life, Gaia, displays a physiology that we recognize as environmental regulation. Gaia itself is not an organism directly selected among many. It is an emergent property of interaction among organisms, the spherical planet on which they reside, and an energy source, the sun.

Over the years the evidence of impact of life on these planetary regulatory processes has built up. An interesting finding in this regard was the discovery that the planetary cycle that replenishes sulphur on land (the sea is rich in sulphur and the land is poor in it) involves a gas dimethyl sulphide that is produced by marine algae and carried to land by wind. Moreover, it was found that this gas has a vital role in seeding clouds, which are critical temperature regulators. Water molecules must condense on nuclei to form clouds -- these nuclei are provided by marine algae Emiliania huxleyii which emit DMS in the first place. 

Another living organism that aids rain-making is Pseudomonas syringae which catalyzes the freezing of water. Since this bacterium is found on crops, scientists speculate that cropping patterns may influence rainfall. This was reported on BBC's website: “Before rain can fall - at least in temperate climates - the water in clouds has to freeze. But - and you may not believe this - sometimes, water doesn't freeze at [0 degrees Celsius]. Pure water will not freeze until -40C, and clouds rarely get that cold. So to get water to freeze you need some help. A catalyst such as soot or dust will do the trick but if you want water to freeze at relatively warm temperatures, say around -5C or -6C, bacteria turn out to be the best "ice nucleators". But these organisms can easily get carried off by the wind and, once airborne in the clouds, pull off the same trick and persuade water droplets to freeze. At least that's the theory. 

"It's a big question," admits Morris. "Are they involved in the events that lead to rain formation? Because if they are - these bacteria are the products of agriculture - does agriculture have any consequence for the amount of rain that could be formed?

There is absolutely no doubt that Gaia has opened up new areas for research and combined disciplines that were used to working in silos. The very nature of the theory requires a comprehension and inquiry must vaster than the narrow confines of disciplines such as atmospheric sciences, ocean studies, evolution or geology. This trend now reflects in our lives as well. Many hope that Gaian thinking may set this right. Philosopher Mary Midgley points this out when she writes: “Our moral, psychological and political ideas have all been armed against holism. They are both too specialized and too atomistic. As many people now point out, that slant is giving us trouble in plenty of other places, notable in many areas of medicine, especially mental illness, as well as over Gaia. Yet we find it very hard to change it.

Gaia as an idea has both scientific and spiritual sides. This is welcome since it helps us connect science to worldliness and makes us feel complete again. Many paint James Lovelock as a hermit scientist who never followed institutional science, has no specialization and worked in a remote corner of the British countryside rather than in a state-of-the-art lab. Lovelock said that it is precisely due to these attributes that he could think large, be moved by his own curiosity and inspiration and break the boundaries between disciplines. Eventually inspired by the first space images of the beautiful blue planet with swirling clouds, he was able to theorize the self-regulation of Earth – true to his instinct, he called it a living earth.

Gaia was born again.

Text and photos by Sahastrarashmi
Lead photo: Earth as seen by the Apollo 17 crew on December 7, 1972/ NASA Earth Observatory