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.)
“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.)
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.)
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 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 mitochondira 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”. 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.” 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 pheronomes. And Flannery suggests potential substances in Gaia that act as “geo-pheronomes”, which act to help maintain conditions suitable to life, including ozone, which shields life from ultraviolet rays, the greenhouses hases, which play a critical role in controllling 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 organisams, 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”. 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, criitically, we humans and our ancestors have been co-evolving with many species of seven milion 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 akes 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 eawsy 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 as a symbol of the way we’ve “destroyed many coevolutionary bonds that lie at the heart of productive ecosystems”.
This may have started making significant impact as much as 30,000 years ago, with our hunting to extinction of the Siberian mammoth. Today the soils are too acid and the nutritional value of the boggy plant matter too low to support much at all – reindeer survive by eating lichens rather than grass, yet a very similar environment supported an abundance of mammoths, woolly rhinos and bison. A key factor, Flannery concludes, is the frozen peat and high acidity make it hard for phospherous and nitrgoen hard for plants to access, but when the mammoth in particular roamed “a copious flow of urine and mammoth droppings provided large volumes of the nutrients at the surface”, and by eating the vegetation so that it didn’t become peat, they reduced acidity. And, Flannery points out, in the last of the Milankovitch cycles, in which the levels of carbon dioxide in the atmosphere fluctuate, some 15,000 years ago, the high was some 15 parts per million of what might have been expected (at 265ppm), it is possible that the rising levels of peat, with its trapped carbon, from plants no longer eaten by the giant grazing animals we’d killed, played a part.
But in a large number of places traditional human societies have worked to preserve their ecosystems – Flannery points particularly to the work of Nobel-winner Elinor Ostrom on sustainable management of commons. And he quotes cases from his own work, of the ways in which “some of the most striking examples concern taboos whose observance requires considerable sacrifice on the part of individuals, yet provides no direct individual benefit… they are informative of how evolution by natural selection can result in cooperation; secondly, they have resulted in the preservation of megafauna species of great importance to the ecosystems they are part of; and thirdly, are informative of the way cultural and physical evolution, working together, may provide a means of humans nurturing the ecosystems that support them”.
He notes how the Telefol people of central Papua New Guinea have a native pine grove that is absolutely protected, where not even a leaf may be picked, which is home to spectacular bird of paradise, with the gaudiest males exhibiting their finery with impunity in the area. And that the long-beaked echidna, an up to 1m-long, 16kg, slow-breeding creature that can live up to 50 years, extinct everywhere except in the central mountains from 40,000 years ago, with the fattest and tastiest flesh of any PNG creature, survived around the Telefol because of a very strong taboo against any harm to it, on pain of disaster to the Telefol. Yet, Flannery points out the belief had previously been so strong that even though hunters often worked alone, and remained alone for several days, so could easily have broken the taboo without anyone know. Yet the survival of the vulnerable species showed how rarely that happened.
One fascinating aspect of this book is the way it looks at events though truly unusual lenses. So Flannery identifies as a critical event in the history of Gaia the rise of “superorganisms” some 120 to 190 million years ago – the cochroaches and then termites, which developed divisions of labour and started “farming” fungi and “herding” aphids for food.
Flannery sees us humans as a similar superorganism, which not only has spread across the globe and gone from small smclan organisations to the United Nations, but also has seen radical specialisation in our abilities and knowledge, accompanied by what Flannery calls “self-domestication”. So while a traditional hunter gatherer might wake in the morning, “find and catch their own food, make or repair their tools and shelter, and defend and educate their families” – all in conditions in which we’d be lucky to survive for days rather than weeks. And we choose to obey thousands of small rules of behaviour that constrict the possibilities of our lives. And, Flannery says, this has been accompanied by loss of brain size – just as our domesticated animals have lost brain size compared to their wild ancestors (or us it is around 10% compared to our ice age ancestors, for wild pigs around 30%). But in return with our new superorganism we’ve got the “glue” of interdependence which has greatly reduced conflict – but also given us the possibilities to destory many of the mechanisms by which Gaia has maintained the possibility of life.
And Flannery identifies many other threats we’ve created as we’ve destabilised billions of years of life-enhancing developments on Gaia. To give just one of his examples there’s mercury – our exposure has trebled since the pre-industrial era (and one in 12 women of childbearing age in the US exceed the recommended level in their blood), and while authorities now insist in many places that the airborne mercury from coal-burning be trapped in stacks using charcoal, no one has yet worked out how to deal with the contaminated charcoal “now accumulating in warehouses and deep mines… just a fire away from releasing the mercury into the atmosphere”. And of course, the real biggies, carbon dioxide.
But this isn’t ultimately, unlike say Lovelock’s The Revenge of Gaia, a depressing book (after reading that I, an optimist, spent two weeks feeling seriously depressed), for Flannery clearly believes (and has put his belief on the line by becoming Australia’s climate commissioner, that it is possible for us to turn all of this around, “that we will use out intelligence to avert catastrophe and seure a sustainable future. We now have most of the tools required to do this, and, after 10,000 years of building ever larger political units, we stand just a few steps away from the global co-operation required…. The immediate challenge is fundamental – to manage our atmospheric and oceanic globnal commons… This does not mean the creation of a world government, simply the enforcement of common rules, for the common good.”
So how we will know if we’re winning? “When profiteering at Gaia’s expense is regarded as and punished as the gravest of crimes — both because it represents a theft from the whole world, present and future, and because it may not remain mere theft but, as its consequences magnify, may become murder or genocide as well.”
And, Flannery says, this a challenge we can’t opt out of. “It’s sometimes argued that if humanity became extinct tomorrow, Gaia would look after herself. That may be true in the very long term – the tens of millions of years – but in the shortterm disaster would befall many species and ecosystems. That’s because they’ve been so deeply compromised that only human effort keeps them functioning effiiciently…. This notion of humans as indispensible elements in the Earth system challenges the concept many of us have about our relationship with nature – for example, that we are somehow apart from it, or just one species among many. The truth is that no other species can perceive environmental problems or correct them, which means that the responsibility for managing this world of wounds we’ve created is uniquely ours.”
He looks at ways we might do this – one is to control nature so that the Earth becomes one giant intensive farm, but “it would lack the resilience and energy budget to keep Earth habitable”. The other is to try to heal the wounds, the damage stretching back 50,000 years that our species has inflicted – not, Flannery says, something that can be done quickly, but should be an “intergenerational ambition” … to have a “rewilding… a reconstruction of vital exosystems on a scale sufficient to allow them to operate optimally without intrusive human management … vanished … ecosystems… more productive and stable than the degraded ones” we have now. And, Flannery says, for Siberia that might need to include bringing back the mammoth, for only it would also allow other grazers to flourish. That, in a way, is only a small part of Flannery’s ambition, but it is at least a vision, a model, of how the world we know might survive, and flourish.
* Published in the US with a different subtitle, “A Natural History of the Planet”.