The Ant and the Steam Engine

Peter Godfrey-Smith

  • BuyA Rough Ride to the Future by James Lovelock
    Allen Lane, 184 pp, £16.99, April 2014, ISBN 978 0 241 00476 0

The Earth’s atmosphere contains about 21 per cent oxygen. What would happen if it contained half, or twice, as much? With half as much, animals like us would struggle to move around and stay alive. Twice as much oxygen, on the other hand, would be wonderful to breathe, but terrestrial life would be consumed by fire; in an atmosphere that rich, even damp wood burns well, fires could not be controlled, and the forests would disappear. Our 21 per cent is a good number, not only because we’re used to it, but because it makes for an active – and not too active – biosphere.

Why is the oxygen percentage what it is? Is it because this is the ‘natural’ level for a planet, or for a planet like ours, given Earth’s size and distance from the sun? Not at all: a chemically ‘normal’ atmosphere for a planet like ours would be very different. Our atmosphere is unusual and its composition is the product of life itself. In particular, the oxygen level that keeps us alive is maintained by other living things. How should we think about this? What sort of account should be given of the shaping of the conditions of life by life itself?

In the 1970s James Lovelock, independent scientist and inventor, proposed the Gaia hypothesis. He argued that the Earth regulates itself, and responds to change, in the same sort of way that a single living organism does. The Earth acts to keep itself alive. Lovelock’s new book, written in his mid-nineties, looks back on his life and work, on the Gaia hypothesis, and on the chemical history of the Earth. He also looks forward, as the title suggests, to the next decades and millennia of the Earth’s history. One of Lovelock’s aims is to relate the large-scale history of the Earth, seen through the lens of Gaia, to the environmental problems we are grappling with today, and he does this in a novel way. The most recent stage in Gaia’s evolution, he says, began in 1712, when Thomas Newcomen succeeded in building the first practical steam engine for pumping water. Newcomen’s engine ran on coal, and his invention set in motion an ongoing chemical interaction. Many early steam engines, including Newcomen’s, were used to control flooding in mines, so the mining and burning of coal facilitated further mining and burning of coal, as well as powering the steamships and trains that came with the invention of more efficient engines. This, for Lovelock, wasn’t just an event in human history but an event in the chemical history of the Earth: ‘Our mistake when we started the Anthropocene [the era of substantial human influence on the Earth] was to fail to notice that inadvertently we were the catalyst of the reaction between the carbon of coal and the oxygen of the air.’ Industrialisation, with all its benefits and ills, followed.

We can’t, as Lovelock sees it, wish this chemical event away, or sensibly blame the industrialists who were the means by which the reaction began and by which it continues to happen. When he talks of ‘our mistake’, he doesn’t mean to criticise the people who didn’t see what was happening at the time – they had no way of realising. Instead, Lovelock regards this history, I think, as a rather natural sequence, perhaps even as something bound to happen; the Earth stored vast amounts of carbon as fuel and also created the oxygen-rich atmosphere needed to burn it off. If sufficiently intelligent animals, like Thomas Newcomen, then evolve, the Earth will burn its stored carbon. The consequences include environmental changes that we will have to learn to live with. Lovelock sometimes describes our future as involving an ‘orderly retreat’ into high-density and highly managed human environments reminiscent of Singapore, and beyond that, perhaps a move from the wet carbon-based chemistry we have now to a silicon-based future, after we ‘merge with our electronic creations’.

Lovelock was born in 1919. At first he trained as a chemist, at the University of Manchester, but has since roved through several scientific fields. He briefly held an academic post at Baylor College of Medicine in Texas, and has had other spells in large institutions, but for most of his career he has worked as an independent scientist and consultant. Early on he designed several instruments for analysing chemicals, especially for detecting tiny amounts of substances in larger mixtures, like the atmosphere. In 1957 he invented an extraordinarily sensitive device for this kind of analysis, the electron-capture detector, which makes use of the tendency for some molecules, including many pesticides, to snare a passing electron that has been liberated by radiation in a gas. The number of electrons captured can be precisely tracked, and indicates the presence of different molecules of interest – including some very important pollutants.

In 1961 Lovelock was invited to work in the US with Nasa on exploration projects aimed at the Moon and Mars. These projects led to the work that eventually made Lovelock famous. He took part in discussions of how life might be detected on other planets, especially with instruments sent on spacecraft. Was there, though, a possibility of answering these questions at long range? Could we see from Earth whether there is life on Mars? Yes, Lovelock argued: it can be done by looking at the chemistry of the planet’s atmosphere, about which we can learn a fair amount using Earth-bound telescopes. Planets with life should have atmospheres that look very different from those of planets without it. In the atmosphere of a planet with life, various chemicals will be ‘out of equilibrium’: they will depart from the stable states that ordinary physical processes will tend to bring about. Lovelock thought we could see, even from here, that Mars has an atmosphere different from that of a living planet.

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