The Revenge of Gaia

Listening to others

by Andrew Teller

Some books have such an impact on their readers that they feel different after having read it: their outlook on life or some long-held belief has been altered irreversibly. The Revenge of Gaia is one of those. Like most people, I had heard about James Lovelock and the Gaia theory, but I had never got round to reading anything about it. James Lovelock’s Revenge of Gaia is his latest book and, admittedly, his testament. It is nevertheless a good place to start for an introduction to his work in general and the Gaia theory in particular.

I must admit that I had always thought that all the talk about global warming was a bit overdone and that gradual changes in world climate would – in due time – lead the lazy majority to mend their ways. This was until I started reading in the above-mentioned book about how its author invented Daisyworld in an attempt to justify his view of the earth as a self-regulating organism. Daisyworld is a very simple and, therefore, imaginary planet. It is populated by only two life species: black and white daisies. The flowers are assumed to find all the nutrients and water they need. Furthermore, due to their differing colours, they reflect different quantities of sunlight and are, therefore, able to alter the temperature of the surface on which they are growing. James Lovelock and his colleague Andrew Watson went on to write all the equations describing this simple ecosystem. There are a dozen or so of them; they include energy balances and relations describing how the planet’s temperature influences the flowers’ growth factors. Since the sizes of the areas covered by each species vary and reflect different quantities of sunlight, the surface temperature of the planet varies and in turn changes the growth factors of the plants, leading to a closed-loop system. It must be added that the equations describing the energy reflected and the growth factors are not linear: the radiation emitted by the daisies follows the well-known Stefan-Boltzmann law involving the fourth power of the temperature and the flowers’ growth factors involve the square of the temperature. All the ingredients needed to give rise to a nonlinear system are there and a nonlinear behaviour we obtain. To use James Lovelock’s own words, the system so modelled is “stable, insensitive to initial conditions and resistant to perturbation.” If the model is instructed to increase the energy given off by the sun, one does indeed observe that the planet’s temperature remains remarkably stable for a fairly wide range of solar luminosity. Beyond a given threshold, however, the self-regulating capacity of the system breaks down; the temperature starts rising rapidly so as to bring both species to extinction. Those who would be tempted to believe that this exercise is purely academic please be reminded that the heat emitted by the sun has been steadily increasing since it first came into being.

Being somewhat familiar with nonlinear systems, I immediately recognised this type of behaviour: relative stability for a wide range of values of the controlling parameters and then sudden departure from the former steady state once these have exceeded a certain threshold. Since I was able to connect this simple model1 to previous knowledge, it did more than countless magazine articles to convince me that climate change is a threat not to be underestimated. It drove home the conclusion that the warnings of the climate experts might not give us much of an advance notice.

Daisyworld provides a bare bones description of the many closed-loop systems governing our ecosystem. A very important one among them concerns carbon dioxide. This explains James Lovelock’s decision to advocate the use of nuclear energy which he sees, as the nuclear industry does, not as the solution but, clearly, as part of the solution. He considers that, if the problems of nuclear energy are certainly not to be overlooked, they are nevertheless dwarfed by those that would result from a failure to address climate change very soon and with means commensurate to the extent of the threat.

Contrary to so many others who claim to be concerned by global warming, James Lovelock has absolutely no taboo regarding nuclear energy and he makes no bones about it. It is even remarkable to see how outspoken he can be when it comes to justifying its use. By contrast, the wording he uses highlights the extent to which we members of the European Nuclear Society apply self-restraint when we speak in favour of nuclear energy. There are many other excerpts of The Revenge of Gaia worth quoting here, but this would deprive you of the pleasure of discovering them for yourselves. This is why I would rather encourage you to buy and read it2 ; I am ready to bet that you will find yourselves recommending it to acquaintances - as I am doing today.

1Feeding “Daisyworld” in an Internet search engine will lead to numerous interesting articles

2 James Lovelock, The Revenge of Gaia, Allen Lane (Penguin Books), London, 2006 (176 p)

Home l Top l Disclaimer l Copyright l Webmaster