A shorter version of this post was published on Blogcritics. (Yes sorry, this is very long, but really you should read the book!)
The latest book by Australia’s foremost science intellectual, Tim Flannery, Here on Earth: A New Beginning should really be read with at least one other person in the room. That way you can look up and say: “Whow, did you know that continental drift ensures the saltiness of the ocean remains constant?” (Flannery explains that while water takes 30,000 to 40,000 years to recycle from evaporation in the ocean through precipitation and hence through soil and rock (picking up salt) and down rivers back to the sea, but over 10 million to 100 million years it passes through hydrothermal vents in the ocean crust, which remove the salt. – p 53)
“Or did you know that soils represent a huge carbon reserve, about 150 billion tonnes, roughly twice that in the atmosphere?” (Flannery explains that soil carbon is made up of humus (which makes it took black and is relatively stable, and can absorb its own weight in moisture), charcoal and roots and other underground parts of plants, which is the most prevalent form, but intensively used croplands have lost from 30 to 75% of their carbon content over the past two centuries. Lots more – though not enough is known to estimate a value – has been lost from poorly managed grazing lands and eroded soils.- p.264)
Or, “gosh, listen to this great Adam Smith quote… ‘The proposal of any new law or regulation of commerce which comes from [the business community] out always to be listened to with great precaution, and ought never to be adopted till having been long and carefully examined, not only with the most scrupulous, but the most suspicious attention. It comes from an order of men, whose interest is never exactly the same as the public, who have generally an interest to deceive and even to oppress the public, and who accordingly have, upon many occasions, both deceived and oppressed it’.” (p. 220)
Or “did you know there were natural nuclear reactors in Africa about 1.8 billion years ago?” (Flannery explains that in the Oklo and Bangombe regions of Gabon, French miners found mostly Uranium-238 – “spent” fiel, rather than the Uranium-235 used in reactors, and concluded that it had been gathered in algal mats in the estuary of an ancient river that flowed over uranium-bearing rocks, and eventually the concentration was sufficient to start a nuclear reaction. – p. 193)
Or “did you know that the first agriculture in the world was probably in Papua New Guinea, 10,000 years ago – earlier than the Fertile Crescent or China?” (Flannery explains it was based on taro and banana, and probably the most productive, supporting the highest rural population densities on earth. And the two most widely planted varieties of sugar cane originated in PNG. – p. 138)
As those examples suggest, Here on Earth is a wide-ranging book – in fact it attempts not just to tell the story of how life has developed on, and shaped, Earth, but how we as life’s conscious beings might ensure that our own and other life continues. It’s really a fleshing-out of James Lovelock’s Gaia hypothesis, with some added politics and sociology that consider us as an important part of the tapestry and history of life.
Flannery takes as his frame what he sees as the two great contrasting scientific approaches to evolution and change – “reductionist science as epitomised by Charles Darwin and Richard Dawkins, and the great holistic analyses of the likes of Alfred Russel Wallace and James Lovelock”, arguing that both are needed to understand life on earth “and what sustainability entails” ([. xvii).
Flannery clearly accepts the idea that Gaia can be seen as a single living organism – but in what way? Flannery points out that we humans are made up of a number of independent or formerly independent elements – our cells are powered by mitochondria that were once independent living things “these partners must have started by forming a loose association, but after more than a billion years of evolution they have become indivisible parts of an organism” – p. 55 And within a human are still independent organisms that make up part of what we think of as us – “Without many of these creatures – for example gut bacteria – we could not exist. These fellow travellers make up 10% of our weight, and are so pervasively distributed over our bodies that were we to take away all ‘human’ cells, a detailed body shadow consisting of them would remain – p 56.” If you look at an individual person that way, it is not so hard to look at the Earth as in some sense a single organism.
But of course the Earth lacks what Flannery calls a “command-and-control” system, but as he says, so do extreme complex ant colonies. They rely on pheromones (and can be remarkably “democratic”, for if a colony is looking for a new home ants will spend longer in places they think best, laying a trail of these chemicals, and the greatest concentration of these will be the place selected for the new home). And Flannery suggests potential substances in Gaia that act as “geo-pheromones”, which act to help maintain conditions suitable to life, including ozone, which shields life from ultraviolet rays, the greenhouses gases, which play a critical role in controlling surface temperature, and dimethyl sulphide, produced by certain algae, which assists in cloud formation. There’s also atmospheric dust, much of which is organic in origin.
He sees as a vital mechanism in making this work coevolution “natural selection that is triggered by interactions between related things… it can act at every level, from that of individual amino acids to entire organisms, and it may not be just a property of life…astromers argue that black holes and galaxies develop an interdependence that’s akin to biological evolution”. (p. 65) In simpler terms, antelope have evolved to run just faster than lions (there’s no advantage in running a lot faster), so lions can catch only the old and the weak. And, Flannery says, critically, we humans and our ancestors have been co-evolving with many species of seven million years. He gives the lovely example of the greater African honeyguide, which feeds solely on the larvae, wax and honey of beehives. When it sees a human, it makes a striking call to attract the human’s attention, “then moves off, stopping frequently to ensure that the person is following it, all the while fanning its tail to display white spots that we visually oriented humans find easy to see. When native Africans reach a hive with the help of a honeyguide, they break it open and often thank the bird with a gift of honey.” Yes, sadly says, this relationship is beginning to break down, because with cheap sugar available, humans can no longer be bothered to seek out honey. Flannery sees this a s a symbol of the way we’ve “destroyed many coevolutionary bonds that lie at the heart of productive ecosystems” (p.68).
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