The Anthropocene epoch has begun

What does that mean and does it matter?

Inside an airport (santiago de Compostela)

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.

 

5 thoughts on “The Anthropocene epoch has begun”

  1. There’s a new book out by my Facebook friend, astrobiologist, David Grinspoon, about this very subject…. “Earth in Human Hands: The Rise of Terra Sapiens and Hope for Our Planet “. There appears to be a few free epub downloads online, but his book is available on Amazon.com, etc. I have read David’s books and he’s an exceptional writer and scientist. Take care!

  2. Geologists define boundaries between geologic periods by reference to clearly defined stratigraphic layers – an empirical boundary that can be measured and observed in the earth – thus the argument for the appearance of strontium 90 from atomic testing and setting 1950 as the date. But the global changes we are experiencing result from factors that may not create a stratigraphic demarcation, or might create a mark that we currently cannot observe or predict. Two very powerful factors that underlay global challenges are 1. the rapid spread since about CE1600 of organisms across ecosystem boundaries and associated catastrophic impacts, and 2. the near logarithmic rise in human population since about that same time, and its catastrophic impacts. Human ingenuity has so far been able to attenuate the negative impacts of these two factors, but systems that get too far out of balance are subject to unpredictable collapse. I’d like to think that human ingenuity will win out, but we are fast outpacing our ability to think up good solutions to global problems.

    1. I would have thought (I may be wrong, being untrained in geology) that markers used to define the beginning of a layer (formation) do not have to be spread all across it. Some markers such as strontium and iridium, and the carbon particles from coal-fired plants mentioned in the article, get spread around the globe, but others are local. New species of mammals (and absence of dinosaurs) mark the first layer of the Palaeocene (don’t they?), but the same species will not be found all across it. If excavation is made into the areas that were once New York or London or Beijing, there will be a layer distinguished by (among other things) huge objects of reinforced concrete, absent from the layers below. Excavation some distance away will find a layer that can be shown to be of the same age, though this particular part of it may be without reinforced concrete.
      I imagine the real reason why a geologist could be uneasy about defining a formation with a beginning so close to us in time is that, unlike all other transitions, it cannot, yet, be observed as a horizon in the ground through which we dig. You could by digging expose the foundations of a skyscraper, but that’s archaeology, not geology. Only in the future will there be an observable layer in the ground thick with near-indestructible bits of human products, so to that extent it’s a prediction, not an observation.

      1. Nor am I a geologist – closest I can come to that is my son who studies geology. But the method of layers is not necessarily precise nor uniform, and therein lies the science (or art). My interest is more in the transition, the change of a system from one state to another, or of collapse. We cannot use that transition to mark the boundary, just the evidence that some transition occurred. And we humans have pushed the global system to the brink – the question is whether we have the capacity recognize this, and regain some stability before the tipping point. An analogy (that works for me as a ship captain) is overloading a vessel; as the ship rolls, the period of recovery changes – rather than regaining center smartly, the ship lags at the extreme ends of the roll – but then seems fine in the period of the roll in the middle. But if one fails to take heed of this sometimes subtle warning sign, at some point the ship will roll to one side, lag, but then fail to recover and very quickly go past the tipping point. If you can stomach the big words, check out this scholarly article that describes indicators of pending failure of general systems:
        http://www.uvm.edu/pdodds/files/papers/others/2009/scheffer2009a.pdf

        Oh, and perhaps to justify this non-astronomical screed, I was lucky enough to have several great naked eye observations of the five planets last winter. Human nature being what it is, with hubris I set my goal to see the same in the morning sky this August. In spite of great viewing on many days, I was foiled during the entire time of ‘prime’ viewing, and as the opportunities dwindled, had to adjust to simply appreciating the sky for what it is, irrespective of getting my sighting or not. But I still made hour long drives to good viewing spots just to enjoy whatever I could see, figuring that the opportunity had passed. Lo and behold, on August 23 the low clouds in the west parted for a few minutes and Mercury appeared. Don’t know if this was a lesson in persistence, acceptance or luck, but it was nice.

        1. That’s great, and you don’t need to “justify” non-astronomical comments; my hope all along has been to make this blog more than astronomical, and I’m now assigning posts to one of other of both of two categories,”astronomy” and “humanity”, though I can’t yet see what difference these categories make to the user.

          I’m packing for a journey (as will be seen in the next post), so will have to enjoy the link about tipping-points on iPad on the train if possible.

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