The magnificent lady
who gathers up the divine powers of heaven and earth
and rivals great An,
is mightiest among the great gods.
She makes their verdicts final
(from the electronic text corpus of Sumerian Literature)
A review of the book by Tim Lenton and Andrew Watson "Revolutions that made the earth" (Oxford 2011)The authors of "Revolutions that made the earth" start from the very beginning with mentioning the name of Gaia for the subject of their book; the story of the Earth's ecosystem. Some people see Gaia as a living being, some as a benevolent goddess, some as a tangle of feedbacks, and others think she just doesn't exist. Yet, out there, there is a pattern, there is a logic. The ecosystem, (aka "Gaia") is there to do something - it is there to dissipate entropy at the fastest possible rate. And it (She) does it very creatively, by means of the endless variety of things and creatures we see around us. We are just starting to understand how exactly this gigantic system works and how it (She) has changed over the eons. It is perhaps the most fascinating story ever told - and it is not yet concluded.
If you know something of this multi-billion year story, you can't but feel sorry for the poor clods who think that the whole issue of climate change reduces to such silly statements as "climate is always changing". The Earth's climate, indeed, has been always changing, but always for some reason. And it is changing now very fast for a reason we understand: the human caused emissions of greenhouse gases. It is a change occurring way too fast for the planetary mechanisms that normally stabilize climate to intervene. The results could be very bad for human beings but Gaia doesn't care for humans. She simply survives.
Unfortunately, humans don't seem to understand the mess they have put themselves in with their carbon emissions. One reason is that the Gaian climate mechanisms are described in scientific papers hidden behind publishers' paywalls and written in obscure and forbidding language. For the non initiate, learning the history of Earth and of its climate from academic papers is not unlike deciphering the hymn of the earth goddess Inanna (an earlier name for Gaia) from Sumerian cuneiform tablets. But the scientific knowledge about Gaia is starting to trickle down from the rarefied world of academia to the real world of ordinary people and the book "Revolutions that made the earth" gives you at least a fighting chance to learn the basics of the subject.
"Revolutions" is written in plain English, not in cuneiform, and the authors made a remarkable effort to be clear and understandable by the layman. That doesn't mean it is an easy book and Lenton and Watson are alerting the reader that "The book covers terrain that ranges in difficulty from easy to strenuous." They are right: sometimes you have the feeling that deciphering cuneiform could be easier than deciphering some sections of this book. That's probably unavoidable: Gaia is a complex system, one of the most complex systems we know of. As for all things which are important and fascinating, learning about the ways of the Goddess requires (and deserves) time and attention.
But if you let yourself to be taken in by the story that the authors of "Revolutions" are telling, well, you don't have to go into the most complicated details (say, the question of the mass independent fractionation of sulphur isotopes). And what a story they are telling! It spans four billion years and went through a series of dramatic events; "revolutions", as the authors correctly term them. They list a total of 8 such events, from the appearance of replicating molecules to the origin of symbolic languages, with humans. Gaia has been stepping up her metabolism toward a higher and higher efficient transduction of solar energy; every revolution has been, basically, a metabolic revolution. Lenton and Watson estimate (p.49) that the metabolic efficiency improvement has been at least of a factor one thousand from the first life forms on Earth to the present biosphere.
So, you ain't seen nothing yet as the planetary engine is revving up and may well go past redline. This is the point that Lenton and Watson are making: revolutions are not over. There is plenty of room for Gaia to grow since the whole biosphere, today, does not capture more than about 2% of the energy arriving from the sun. So, we may be ready for a new jump that could bring the complexity of the ecosystem to levels unthinkable up to now. What this new revolution could be, exactly, is difficult to say. Here, the chapter of "Revolutions" describing the future of the ecosystem is - I must say - the least satisfactory of the book. It tries an impossible task: a few pages are just not enough to tackle such a gigantic issue. It is sure, anyway, that revolutions are never painless and it would be wrong to think that the new metabolic jump will save humankind from the self-inflicted disaster of global warming. It may save just a few of us, or perhaps none. Gaia doesn't care for humans, she simply survives. We will see what the future has in store for us. In the meantime, I am reading "Revolutions" a second time - as it deserves.
