John Gribbin writes:

Jim Lovelock (never ‘James’) is remembered as the father of the Gaia hypothesis: the idea that Earth is a self-regulating living organism. Few accepted his argument that this should be elevated to the status of a theory, even though it generated predictions about environmental changes that were borne out by subsequent observations. As a heuristic model, however, Gaia profoundly influenced thinking about the environment and how we interact with it, giving rise to the field of Earth-system studies.

Lovelock was primarily an inventor, spending most of his career as an independent scientist funded by the income from his inventions and therefore free from the constraints of an academic post. His thinking about environmental issues stemmed from observations made with his inventions. His most notable device was the electron capture detector, which ‘sniffed out’ traces of compounds in the air. This unexpectedly revealed the spread of chlorofluorocarbons around the globe and the build-up of the pesticide DDT in the environment, leading to restrictions on the use of these substances.

He was working as a consultant for NASA’s Jet Propulsion Laboratory in Pasadena, California, in 1965, when French astronomers reported infrared spectra showing that the atmosphere of Mars consisted mainly of carbon dioxide in stable equilibrium. He realized that Mars must be ‘dead’, because life can exist only in systems far from equilibrium, feeding off a flow of energy. He inferred, with biologist Lynn Margulis, that living things determine the atmospheric composition of a living planet such as Earth and maintain conditions suitable for life through feedbacks. The pair published the idea in 1974 (J. E. Lovelock and L. Margulis Tellus 26, 2–10; 1974), the year that Lovelock was elected a Fellow of the Royal Society. His legacy is enshrined in the now-standard idea of searching for signs of life on exoplanets by studying their spectra — the Lovelock test. [Continue reading…]