James Lovelock, a freelance chemist, ecologist and naturalist, has died aged 103.
The Associated Press reported that he died on Tuesday evening at his home in South West England “surrounded by his family”. The family said his health had deteriorated after a bad fall but that until six months ago Lovelock ‘was still able to walk along the coast near his home in Dorset and take part in interviews’.
In a 1965 article published in Nature, Lovelock, inspired by the search for possible life on Mars, noted how the Earth remains in a vital imbalance between two stable extremes, like the frozen wasteland of Mars or a hellish world like Venus. There are active mechanisms on Earth that keep average temperatures around 13.9 degrees Celsius, despite the sun’s varying activity, or regulate atmospheric gas levels.
In 1971, microbiologist Lynn Margulis joined Lovelock, emphasizing the importance of life to this hypothesis., arguing that natural selection could explain the development of a self-regulating system. Organisms do not deliberately manipulate a system so that it can support them; however, if an organism harms its environment, making its survival unlikely, it will naturally be selected and removed from the system.
They followed novelist William Golding’s suggestion and called this idea the Gaia hypothesis, after the personification of Earth in Greek mythology. This name inspired the notion of “Earth as a living planet”, but it is correct to say that the Gaia hypothesis considers the spheres of the Earth – the lithosphere, the hydrosphere, the biosphere and the atmosphere – as interconnected and self-regulating systems.
Plate tectonics is like life (as far as we know) a unique feature of Earth. In addition to the density and petrological composition of the Earth’s interior, active plate tectonics appear to depend on the existence of liquid water on the planet’s surface. Without an atmosphere, the Earth would be too cold to hold water in liquid form. The presence of the atmosphere is influenced by the weathering of rocks, volcanism, the distribution of land and seas, but also the activity of life forms absorbing or releasing gases. Plate tectonics itself changes the Earth’s surface and its environments, forcing life to adapt and evolve.
The Gaia hypothesis survives today as Earth System Science. This new field of science studies the interactions and feedbacks, through the flows of matter and energy, between the cycles, processes and spheres of the Earth’s subsystems – atmosphere, hydrosphere, cryosphere, geosphere, pedosphere, lithosphere , biosphere and even the magnetosphere – as well as the impact of human societies on these components.