The term is meant to reflect the fact that humans are transforming the face of the planet as deeply as the asteroid did at the end of the dinosaur era, or as deeply as the Earth ripping open at the end of the Permian. Therefore, they argue, we can't call this era by the old biological or geological classifications; it is an era in which the chemistry of the air, the acidity of the seas, the temperature, the albedo, the animal and plant species, are all defined by humans. It is, they say, the Anthropocene.
Greer is not fond of the new term, and gives a good argument as to why, which I won't sum up here. I did, however, contribute my own thoughts:
You make an interesting point, JMG.
A bit of rumination on your theme: I’m not personally bothered by the term “Anthropocene,” simply because all these divisions are, to a point, imperfect teaching tools created by and for humans. Our divisions reflect a physical reality, of course – there really is a K-T boundary about 65 million years down through the rock, for example – but as you mention, they represent modern scientists building on and adapting the terms handed down to them from their predecessors, who did the same, back to the beginnings of science.
Someone doing the whole thing over from scratch might make the major division the Great Oxygenation Event – or the Iron Rain, as I call it when teaching my daughter – when the seas and sky became saturated with oxygen. It would be about halfway through the Earth’s history, and it changed the planet in what, for us and most living things, are the most tangible ways – the seas and sky turned blue, the iron rained out of the sea, and most life was wiped out. Or before and after eukaryotic cells, or Hox genes, or land vertebrates, or any number of other game-changing developments.
Our divisions tend to be biased towards what we can see, because we can see it, and biased toward animals rather than plants, because we’re animals; the spread of mammals also coincided with the spread of flowers, fruits and grasses, which changed the world more than mammals did, yet we think of the Age of Dinosaurs and the Age of Mammals. We divide eras or divisions into single-digit groups of three or seven, rather than thirty-three or five thousand and seven, partly because that’s what human brains can remember.
I mentioned in a comment some weeks ago the difference between fact and truth; facts are data, but how we put them together reflects the truths we believe in. It doesn’t mean we’re not describing reality – we are, and can back it up with evidence. But we can describe the same reality in a number of different ways.
In other words, it’s like the debate over whether Pluto is a planet – no one can deny that there are several large bodies and many small ones orbiting the sun, but the inner rocky planets are small, solid spheres, asteroids are smaller, solid potato-shapes, gas giants like Jupiter and Saturn are stillborn stars, and Pluto and the comets are dirty snowballs with weird orbits.
We group the four rocky spheres and the four gas giants together and call them “planets,” and possibly Pluto if we feel like it, but not the asteroids or comets. The planets and their orbits are proven facts; how we group them with our human language reflects our human truths. We group them into eight or nine partly because we remember that a lot more easily than the several million smaller bodies.
We called Pluto a planet when we discovered it in the 1930s, partly because society believed in progress and wanted to celebrate new discoveries, partly because the growing power of the USA in the 1930s wanted to claim its own astronomical discoveries, and partly because Percival Lowell (whose initials, supposedly, were part of the reason it was called Pluto) had long predicted there would be another planet out there, and people thought Pluto was it.
What I’m getting to here is, if referring to the current ecological disruption as an era helps us take it more seriously, call it an era – it is from our human perspective. It won’t be an era to God, who -- as Aquinas pointed out -- exists outside of time, but we can’t second-guess Him anyway.