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Officially, the Holocene is still running today. You have lived your entire life in the Holocene, and the Holocene has constituted the geological “present” for as long as there have been geologists.But if we now live in a new epoch, the Anthropocene, then the ICS will have to chop the Holocene somewhere. It will have to choose when the Holocene ended, and it will move some amount of time out of the purview of the Holocene working group and into that of the Anthropocene working group.

This is politically difficult. And right now, the Anthropocene working group seems intent on not carving too deep into the Holocene. In a paper published earlier this year in Earth-Science Reviews, the Anthropocene working group’s members strongly imply that they will propose starting the new epoch in the mid-20th century.

Some geologists argue that the Anthropocene started even earlier: perhaps 4,000 or 6,000 years ago, as farmers began to remake the land surface.“Most of the world’s forests that were going to be converted to cropland and agriculture were already cleared well before 1950,” says Bill Ruddiman, a geology professor at the University of Virginia and an advocate of this extremely early Anthropocene.

“Most of the world’s prairies and steppes that were going to be cleared for crops were already gone, by then. How can you argue the Anthropocene started in 1950 when all of the major things that affect Earth’s surface were already over?”Van der Pluijm agreed that the Anthropocene working group was picking 1950 for “not very good reasons.”“Agriculture was the revolution that allowed society to develop,” he said. “That was really when people started to force the land to work for them. That massive land movement—it’s like a landslide, except it’s a humanslide. And it is not, of course, as dramatic as today’s motion of land, but it starts the clock.”

This muddle had to stop. The Holocene comes up constantly in discussions of modern global warming. Geologists and climate scientists did not make their jobs any easier by slicing it in different ways and telling contradictory stories about it.

This process started almost 10 years ago. For this reason, Zalasiewicz, the chair of the Anthropocene working group, said he wasn’t blindsided by the new subdivisions at all. In fact, he voted to adopt them as a member of the Quaternary working group.“Whether the Anthropocene works with a unified Holocene or one that’s in three parts makes for very little difference,” he told me.In fact, it had made the Anthropocene group’s work easier. “It has been useful to compare the scale of the two climate events that mark the new boundaries [within the Holocene] with the kind of changes that we’re assessing in the Anthropocene. It has been quite useful to have the compare and contrast,” he said. “Our view is that some of the changes in the Anthropocene are rather bigger.”

Zalasiewicz said that he and his colleagues were going as fast as they could. When the working group group began its work in 2009, it was “really starting from scratch,” he told me.While other working groups have a large body of stratigraphic research to consider, the Anthropocene working group had nothing. “We had to spend a fair bit of time deciding whether the Anthropocene was geology at all,” he said. Then they had to decide where its signal could show up. Now, they’re looking for evidence that shows it.

This cycle of “glacials” and “interglacials” has played out about 50 times over the last several million years. When the Holocene began, it was only another interglacial—albeit the one we live in. Until recently, glaciers were still on schedule to descend in another 30,000 years or so.Yet geologists still call the Holocene an epoch, even though they do not bestow this term on any of the previous 49 interglacials. It get special treatment because we live in it.

Much of this science is now moot. Humanity’s vast emissions of greenhouse gas have now so warmed the climate that they have offset the next glaciation. They may even knock us out of the ongoing cycle of Ice Ages, sending the Earth hurtling back toward a “greenhouse” climate after the more amenable “icehouse” climate during which humans evolved.For this reason, van der Pluijm wants the Anthropocene to supplant the Holocene entirely. Humans made their first great change to the environment at the close of the last glaciation, when they seem to have hunted the world’s largest mammals—the wooly mammoth, the saber-toothed tiger—to extinction. Why not start the Anthropocene then?He would even rename the pre-1800 period “the Holocene Age” as a consolation prize:

Zalasiewicz said he would not start the Anthropocene too early in time, as it would be too work-intensive for the field to rename such a vast swath of time. “The early-Anthropocene idea would crosscut against the Holocene as it’s seen by Holocene workers,” he said. If other academics didn’t like this, they could create their own timescales and start the Anthropocene Epoch where they choose. “We have no jurisdiction over the word Anthropocene,” he said.

Ruddiman, the University of Virginia professor who first argued for a very early Anthropocene, now makes an even broader case. He’s not sure it makes sense to formally define the Anthropocene at all. In a paper published this week, he objects to designating the Anthropocene as starting in the 1950s—and then he objects to delineating the Anthropocene, or indeed any new geological epoch, by name. “Keep the use of the term informal,” he told me. “Don’t make it rigid. Keep it informal so people can say the early-agricultural Anthropocene, or the industrial-era Anthropocene.”

“This is the age of geochemical dating,” he said. Geologists have stopped looking to the ICS to place each rock sample into the rock sequence. Instead, field geologists use laboratory techniques to get a precise year or century of origin for each rock sample. “The community just doesn’t care about these definitions,” he said.

in the broadest sense we have to embrace the characteristics, good and bad, that make humans such a rare thing — a species that has become a planet-scale force.

Once you begin to get the many feedbacks bouncing off each other and bouncing off the Earth system, it’s going to be very hard to follow what’s going to happen, particularly biologically…. One could not imagine, at the very end of the Cretaceous, the beginning of the Tertiary, that the mammals — these itty-bitty little squeaky furry things, would take over – effectively taking the position that the dinosaurs held for so long. All we can say is that, for sure, it will be different. We’re going down a different trouser leg of history.

on whether it’s possible to have a “good Anthropocene.” Kolbert’s Twitter post last spring nicely captured their view:

Taking full ownership of the Anthropocene won’t be easy. The necessary feeling is a queasy mix of excitement and unease. I’ve compared it to waking up in the first car on the first run of a new roller coaster that hasn’t been examined fully by engineers.

That’s a very different sensation than, say, mourning the end of nature. It’s more a celebration, in a way — a deeper acceptance of our place on the planet, with all of our synthetic trappings, and our faults, as fundamentally natural.

There’s little predictability in how things will play out after this anthropogenic jolt, especially in the living world. [More on the “great acceleration” behind the jolt is here.]

“The way I would like to see it is in, say, 100 years in the future the London Geological Society will look back and consider this period…a transition from the lesser Anthropocene to the greater Anthropocene.”

Fully integrating this awareness into our personal choices and societal norms and policies will take time. It is “the great work,” as Thomas Berry put it.

Technology alone will not do the trick. Another keystone to better meshing humanity’s infinite aspirations with life on a finite planet will be slowly shifting value systems from the foundation up

Edward O. Wilson’s “Biophilia” was a powerful look outward at the characteristics of the natural world that we inherently cherish.

Now we need a dose of what I’ve taken to calling anthropophilia, as well.

We have to accept ourselves, flaws and all, in order to move beyond what has been something of an unconscious, species-scale pubescent growth spurt, enabled by fossil fuels in place of testosterone.

We’re stuck with “The World With Us.” It’s time to grasp that uncomfortable, but ultimately hopeful, idea.

Defining the Anthropocene: nine sites are in the running to be given the ‘golden spike’ designation

Mentioning the Jurassic period, for instance, helps scientists to picture plants and animals that were alive during that time

“The Anthropocene represents an umbrella for all of these different changes that humans have made to the planet,”

Typically, researchers will agree that a specific change in Earth’s geology must be captured in the official timeline. The ICS will then determine which set of rock layers, called strata, best illustrates that change, and it will choose which layer marks its lower boundary

This is called the Global Stratotype Section and Point (GSSP), and it is defined by a signal, such as the first appearance of a fossil species, trapped in the rock, mud or other material. One location is chosen to represent the boundary, and researchers mark this site physically with a golden spike, to commemorate it.

“It’s a label,” says Colin Waters, who chairs the AWG and is a geologist at the University of Leicester, UK. “It’s a great way of summarizing a lot of concepts into one word.”

But the Anthropocene has posed problems. Geologists want to capture it in the timeline, but its beginning isn’t obvious in Earth’s strata, and signs of human activity have never before been part of the defining process.

“We had a vague idea about what it might be, [but] we didn’t know what kind of hard evidence would go into it.”

Years of debate among the group’s multidisciplinary members led them to identify a host of signals — radioactive isotopes from nuclear-bomb tests, ash from fossil-fuel combustion, microplastics, pesticides — that would be trapped in the strata of an Anthropocene-defining site. These began to appear in the early 1950s, when a booming human population started consuming materials and creating new ones faster than ever.

Why do some geologists oppose the Anthropocene as a new epoch?“It misrepresents what we do” in the ICS, says Stanley Finney, a stratigrapher at California State University, Long Beach, and secretary-general for the International Union of Geological Sciences (IUGS). The AWG is working backwards, Finney says: normally, geologists identify strata that should enter the geological timescale before considering a golden spike; in this case, they’re seeking out the lower boundary of an undefined set of geological layers.

Lucy Edwards, a palaeontologist who retired in 2008 from the Florence Bascom Geoscience Center in Reston, Virginia, agrees. For her, the strata that might define the Anthropocene do not yet exist because the proposed epoch is so young. “There is no geologic record of tomorrow,”

Edwards, Finney and other researchers have instead proposed calling the Anthropocene a geological ‘event’, a flexible term that can stretch in time, depending on human impact. “It’s all-encompassing,” Edwards says.

Zalasiewicz disagrees. “The word ‘event’ has been used and stretched to mean all kinds of things,” he says. “So simply calling something an event doesn’t give it any wider meaning.”