What does that mean and does it matter?
Yes: it’s a topic of debate, and is a way of expressing something important for our planet.
Geologists divide time into the Palaeozoic, Mesozoic, and Cenozoic eras (“ancient life, middle life, recent life”). The Mesozoic era lasted 186 millions years and is divided into the Triassic, Jurassic and Cretaceous periods. The Cenozoic era has lasted only 66 million years, down to now, and is rather desperately divided into epochs called Paleocene, Eocene, Oligocene, Miocene, Pliocene, Pleistocene, and Holocene (“ancient recent, dawn recent, few recent, less recent, more recent, most recent, wholly recent”) which get progressively shorter. So we are living in our little Holocene, which began only 10,000 years ago with the ending of the last ice age.
Or are we? The argument has arisen that Homo sapiens has made so much difference to conditions on Earth’s surface that we should declare the beginning of a new geological epoch, the Anthropocene.
(Anêr, stem andr-, is Greek for “man,” the male; anthrôpos is “man” the species, so the Greeks did at least have a gender-free word, though it looks suspiciously like “man-faced” in origin. I’ve seen anthropocene spelled as anthropogene, as if it meant “man-generated,” like the words that end with -genous, and that might actually be more appropriate.)
I don’t know who started the Anthropocene suggestion, but since 2009 a Working Group appointed by the International Geological Congress has been thinking about it. I read that among geologists, and others, there is strong division of opinion, many being scornful of such a change, so soon into the Holocene!
I think it is absolutely obvious, and I’ve been saving up to say so. What I was waiting for was to take a few photographs like the one above (which happens to be the inside of a relatively small airport, at Santiago de Composela). I took some, as I found myself cowed by ponderous examples of construction, but they’re lost; I’ll yet take some more to show you what I mean.
But now the Working Group has decided, apparently on August 29. It voted, 30-3, to recommend that the Anthropocene should be considered to have started, and it is up to the Congress to accept it.
The starting date for the epoch has to be pretty arbitrary; they’ve picked 1950. I had been wondering whether it should be the start of the Industrial Revolution, or of agriculture. But this appears a difficulty only because we are near to it. Most previous geological transitions were soft, taking thousands of years (there was no exact “end of the ice age”).
The evidence that the Anthropocene has started includes radioactive elements from nuclear tests; the nation-sized amounts of plastic (a previously unknown material); the steep increase of greenhouse gases in the atmosphere and acid in the ocean; and huge increase in the bones of a few species (chickens, sheep, cows), while so many others are undergoing a mass extinction faster than any of the previous four, all of which brought the ends of major geological periods.
But what had impressed me is that the change is visually obvious.
Where there were forests and savannas, there are fields, expanses of asphalt, tunnels, hard-embanked rivers, and towering structures of concrete and steel. Layers are distinguished from each other by their composition. Fossils of ferns, mollusks, trees; sand, lava; termite cities nearly thirty feet high. Iron railings, sides of ships, overpasses, termite cities forty miles across.