James Lovelock’s Gloomy Vision

James Lovelock, renegade Earth scientist and creator of the Gaia hypothesis, has written a gloomy new book called “Revenge of Gaia”, in which he argues that we should be stashing survival manuals, printed on good old-fashioned paper, in the Arctic where the last few breeding pairs of humans will likely be found after a coming climate catastrophe. The book is not published in the U.S. yet, but it is available from amazon.co.uk. Lovelock has never been one to shrink from a bold vision. What is it he sees now?

Gaia In the first biogeochemistry class I took, I was assigned to read the first few chapters of Lovelock’s 1978 book, “Gaia: A new look at life on earth”. Since then, I have assigned those same chapters to every biogeochemistry class I have ever taught. Lovelock wrote very eloquently about the eerie stability of the earth system. The sun has been warming throughout its lifetime, and yet the climate of the earth has remained stable between the relatively narrow range of the boiling and freezing points of water. This observation was labeled the “faint young sun” paradox by Carl Sagan [1972], and now has at least a partial explanation in terms of the weathering of silicate rocks, the silicate weathering thermostat [Walker et al., 1981]. Lovelock also points out that the oxygen concentration of the atmosphere has been remarkably stable over the half-billion years since multicellular life appeared in the fossil record, never high enough to explode (doubled atmospheric oxygen would lead to unstoppable continent-scale forest fires), nor low enough to wipe out the animals. Nitrogen, Lovelock points out, ought thermodynamically to exist as nitrate dissolved in the oceans; the reason that most of Earth’s nitrogen exists as nitrogen gas in the atmosphere is because of life.

Lovelock’s bold leap was to envision life on Earth as a single unified organism, capable of regulating the environment on Earth for its own well-being, analogous to the way that you or I regulate the temperature and chemistry of our bodies. A weak version of the Gaia hypothesis would state that the geochemistry of the biosphere is regulated by negative feedback mechanisms, many of which include the effects of life on Earth as integral components. This statement is no longer controversial among Earth scientists. A stronger version of the Gaia hypothesis might conclude, as Lovelock did, that methane is produced by bacteria because Gaia requires a flux of hydrogen to the stratosphere and hence to space, as a long-term balance of her oxidation state. A new idea in “Revenge of Gaia” is that we animals dispose of excess nitrogen in a bioavailable form as urine, rather than saving water and energy by exhaling it as the biologically less available nitrogen gas, because Gaia prefers for us to keep the nitrogen available for plants.

The strong Gaia hypothesis raises issues of altruism and cooperation among different components of Earth’s biota. I personally don’t understand how a Gaian biota would be stable, in the face of competition between organisms. If an organism spent metabolic energy for the common good, would it not be out-competed by another more selfish organism? The evolution of Gaia is another difficulty. Darwinian evolution is essentially a process of trial and error. Evolving a Gaia leaves very little room for error.

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