Markers on Planet Earth

We are in a new geological epoch, the Anthropocene. A single species has become a major geological force, up there with erosion, volcanism, continental drift; reshaping the land and decimating many of the other thousands of species. There is now no serious doubt of that. I’ve talked about it before.

Anthrôpos is Greek for “human being.” The -cene part is from Greek kainos, “new.” This epoch is the eighth in the series since the end of the Cretaceous period 66 million years ago: Paleocene (“ancient new”), Eocene (“dawn new”), Oligocene (“few new”), Miocene (“less new”), Pliocene (“more new”), Pleistocene (“most new”), Holocene  (“wholly new”). Together making the Cenozoic era, “new life.”

(An inconvenience in talking about geology is that, in its time scale, eons are divided into eras, those into periods, those into epochs, those into ages. So there is no general word left for a unit of time. We can’t just freely refer to an age or period as we would in ordinary discourse.)

Definition by when it started

Forty scientists (called the Anthropocene Working Group) have been tasked with fixing the beginning of the Anthropocene. They are trying to agree on a time, and even a place, where there is the first “marker” of it.

If you dig down through the Cretaceous layer in England, you come to a level where chalk changes to limestone. That is a marker, though it doesn’t happen the same way all over the world.

The International Union of Geological Sciences has to tick a box. It needs an agreed marker before it can formally recognize the Anthropocene.

The ideal marker would be a substance that is found at the bottom of a layer all over the world. Such was the iridium found at the boundary between the Cretaceous and the layer above. It had been scatted around the world by the impact of an asteroid, which extinguished 75 percent of all species on Earth. So in that case there is a definite marker, the iridium, and a location, the Chicxulub crater in Mexico, where the asteroid struck.

But most transitions from epoch to epoch do not happen at an instant. The gradation from the top clay or loam of a layer to the next has a thickness, often with laminations – thin layers laid down by annual floods or by sandstorms. The thickness, I assume, represents some thousands of years as conditions changed. The epochs are distinguished from each other by different compositions of fossils, testifying to different assemblages of living things. I first learned some geology from The Children’s Encyclopaedia. For a period, it would have a picture of a scene, such as tree ferns and giant horsetails and dinosaurs hunting each other. One understood that a geological epoch was defined by a description of its contents, at least as much as by any marker of its beginning.

Some of the markers suggested for the start of the Anthropocene are plutonium from nuclear blasts, soot from fossil fuel, artificial fertilizes and pesticides and other chemical pollutants, microplastics, chicken bones, and black layers on sea beds caused by deoxygenation of water caused by algal blooms caused by fertilizers. And “tiny spheroidal carbonaceous particles (SCPs), a type of tough fly ash only produced by the high-temperature burning of coal or heavy oil.”

Several of these would date the onset of the epoch to the end of World War Two. Or the 1950s, when plastics started multiplying. (Nylon has all but replaced silk.) One would give a precise date and place, 1952 November 1, the first H-bomb test, over Eniwetok atoll. Another suggestion is 1610, for the mass colonization of the Americas that nearly wiped out its natives. How about the industrial revolution? And I remember a suggestion of the beginning, far back, of rice cultivation, which not only began mass agriculture but transformed landscapes into lagoons and terraces.

Definition by what it’s like

Those are markers in the sense of events. But a geological layer created during an epoch has contents, not necessarily present at its beginning, but so distinctive as to be markers in the sense of characteristics.

You could already dig down in places into a layer of soil formed by debris in the Anthropocene, and notice contents in it – cement fragments, television aerials, car wheel hubcaps, batteries, airplane fragments, bullets.

But the geologists, I think, have a longer view: the epoch they define should be recognized as an epoch by geologists of the far future, if any. We look back on the Jurassic and recognize it as a stratigraphic unit with its characteristic dinosaurs and mouse-sized mammals. It will be theoretically possible to look back on the Anthropocene and recognize it as a unit, with contents not seen before it. In it, or sticking up out of it, will be enormous and indestructible structures of steel and concrete and glass.

The more extensive descriptive markers of the Anthropocene, brought about by human activity, already show. Some make visible geological change. Rising sea level causes changes in coastlines. Humans are shifting 24 times more material than rivers do. Vast areas of land surface are covered by buildings and asphalt and other hard paving.

Other changes are not mineral, but affect all life-forms.

In the atmosphere, the amount of carbon dioxide has increased by 47 percent, and of methane 2.6 percent. They (methane more powerfully) slow the sun’s heat from escaping, thus heating the land and ocean. This changes the environments to which all species have adapted. Carbon getting into the ocean acidifies it and kills corals, which are not only geological formations but havens of biodiversity.

On the land surface, vast areas are covered by monoculture, with a single crop, inhibiting other life. An area of forest the size of Portugal is destroyed every year.

Of the world’s mammals, humans are now, by mass, 36 percent; 60 percent are “livestock,” slave animals kept for human consumption. The rest – from whales and tigers and monkeys to shrews – have shrunk to 4 percent. Of birds, captive chickens are by far the most numerous. Wild animals in general have been reduced by 70 percent. Invasive species, brought for instance in the ballast water  of ships, have replaced the biota of whole regions.

And?

The article I read about the Anthropocene Working Group ended: “What do we do about it?”

The Anthropocene is a monster. It cannot be killed; it could be somewhat tamed. Individuals can do a little. A person who wants to be in the forefront of the fight can avoid meat, flying, driving, plastics (just about impossible now because of packaging); maybe other things, plant trees, switch off lights and unused devices, avoid bottled water. But we are using spoons to bale out a flood.

Only governments and corporations and law courts are big enough to fight a monster. They must ban coal, raise taxes on fossil fuel, fine polluters more than they profit by their pollution, foster onshore wind farms and ocean current power and solar power and reforestation and vertical farms. So individuals have one more weapon: yell at governments with protests and votes.

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