This week was lectured by Prof. Tim Lenton, and this module keeps setting off lightbulb moments for me.
How did life on earth get to be self-regulating?
What is life, and what is its effect on the planet?
James Lovelock had started looking at the composition of atmospheres of different planets while working at NASA. He was influenced by Erwin Schrödinger’s ideas, particularly from his book What is Life? (1944). Schrödinger proposed that living organisms maintain order and avoid entropy by exchanging energy and matter with their environment.
Lovelock extended this idea, suggesting that life on a planetary scale could also maintain a state of order in the form of atmospheric disequilibrium. Hence, by looking for planets with atmospheres in chemical disequilibrium, we might identify the presence of life. A living planet, like Earth, has an atmosphere containing a mix of gases that are out of balance and would not exist together without continuous biological processes. For example, Earth’s atmosphere contains both oxygen and methane, which would normally react and neutralise each other over time. The persistence of such gases in an atmosphere suggests ongoing biological activity replenishing them. Looking at the chemical compositions of Mars and Venus’ atmospheres however, Lovelock concluded that there was no life there as their atmospheres were in chemical equilibrium, so there was little point in sending life-detecting missions.
This was the foundation of the Gaia hypothesis. Life on Earth is creating and regulating not just the atmosphere, but also the climate, creating sustainable conditions for life. Atmospheric homeostasis by and for the biosphere. Organisms contributing to self-regulating feedback mechanisms.
Tim Lenton and Hywel Williams’s work on the flask model appeared to support the Gaia hypothesis.
We looked at disputes over the hypothesis:
- That it anthropomorphises Earth or takes a teleological approach, implying that the planet has some purpose to maintain and support life.
- That it is incompatible with the theory of natural selection (Richard Dawkins posited that since evolution operates at the level of individual organisms and genes, it is unclear how cooperative planetary-level regulation would evolve; genes are out for themselves) – Ford Dolittle attempted to reconcile the Gaia hypothesis and Darwinian natural selection in his book Darwinizing Gaia, suggesting that emergent properties of independently evolved components of an ecosystem might appear to resemble self-regulation on a planetary scale.
- That it is vague or unfalsifiable, more effective as a metaphor or a philosophical concept than a scientific hypothesis.
Another criticism of Gaia was that the Earth has not always been stable, for example during the time of the Snowball Earth hypothesis, when the entire surface of the planet was supposedly covered in ice and would have been inhospitable to life. The response to this is the idea of sequential selection, where unstable systems are effectively cancelled out and reset by eliminating destabilising effects.
The Gaia hypothesis made me think about soil. Soil, by definition, contains a combination of minerals, water, air and organic matter. Crucially also, though, organic matter includes biological life, from bacteria to fungi, springtales and worms. Soil that does not contain life, that is not alive, is not soil. It’s a collection of minerals. Soil is influenced and regulated by the biological life within it – it cycles nutrients, creates pore spaces and exudes substances that act as a glue holding aggregates together. The permaculture principle that applies here is that everything gardens. Gaia feels like an expression of the same principle, but at a planetary scale. Our Earth is alive. Whether you accept the Gaia hypothesis as a scientific hypothesis, or simply as a metaphor or a philosophical construct, doesn’t particularly matter to me. It’s a powerful way to think about the planet and our relationship with it.
Gaia 2.0
We moved on to Gaia 2.0, an evolution of the Gaia model that sees humanity taking a more intentional and conscious role in regulating Earth’s systems – self-aware self-regulation for the Anthropocene.
How do we think more like Gaia? What aspects of Gaia could we learn from?
For me, this means biophilia and deep engagement with the natural world. Undoing hundreds of years of ingrained teaching that humanity is at the top of the hierarchy of life, that we are life, we are nature.
It means reduce, re-use and recycle, closed-loop systems, doughnut economics and sufficiency as a movement.
It means an agroecological food system that costs in the importance of sustainability, resource usage, recycling and knowledge – including the indigenous knowledge systems that share the perception of Earth as a living, interconnected entity with which we have a relationship based on reciprocity.
Finally, to me, it means acknowledging that if we overshoot and collapse, we are punishing ourselves first and foremost. Gaia may eliminate destabilising elements and reset, it is not a benevolent entity that cares about our fate. Gaia will not end, only we will. We need Gaia more than Gaia needs us.
Featured image: Luke Jerram’s art installation Gaia seen at Exeter Cathedral.