Moving On from the Anthropocene

Recognizing the Anthropocene as a Geological Event Allows for a Radically Humanist Approach to Climate and the Environment

By Leigh Phillips

The decision of geologists to decline formal recognition of the Anthropocene as an epoch, with a start date in the 1950s, has led to a furious backlash in some quarters.

In March of this year, after some 15 years of deliberation by the Anthropocene Working Group (AWG), the Subcommission on Quaternary Stratigraphy voted to reject its proposal to alter the Geological Time Scale (GTS) and recognize the Anthropocene as an epoch.

In response to the decision, soil scientist Johan Rockström—also the head of the renowned Potsdam Institute for Climate Impact Research and one of the originators of the concept of planetary boundaries—went so far as to denounce the entire discipline of geology. “Big Mistake,” he said, posting on Twitter/X. “But geologists have often found themselves on the wrong side of scientific evidence, e.g., on Anthropogenic climate change.”

Responding to Rockström’s volley, the secretary-general of the International Commission on Stratigraphy tossed back his own contumely, calling the other side “sore losers.”

Ouch.

Beyond the vituperation and snark of this bunfight, the more serious suggestion from Rockström’s side in the debate is that their opponents are preventing humanity from coming to grips with the profound scale of what we have wrought. As New Yorker journalist Elizabeth Kolbert, self-described “Anthropocene partisan,” wrote in her coverage of the row: “It’s a succinct way of communicating a messy and profoundly consequential reality. Human activity has become the major driver of change on Earth.”

Within the AWG itself, there were opponents of recognition of the Anthropocene as an epoch within the GTS. Ecologist Erle Ellis ultimately resigned from the AWG because he felt that the concept was too narrowly defined.

And key to the opponents’ argument is the fact that geologically profound anthropogenic impacts run much further back. A wide range of historical events have been cited, from the Columbian Exchange after 1492, to the advent of cities perhaps 7,500 years ago, to the Neolithic Revolution and advent of agriculture some 11,700 years ago, or even the advent of fire by Homo sapiens (and Neanderthals) some 300 or 400,000 years ago. They argue that humanity’s geologically consequential impacts on the rest of nature are time-transgressive, and therefore cannot fit easily into a single date on the calendar.

From Gibbard et al. (2022)

Ellis and his colleagues have suggested continued use of the Anthropocene, but argue that it should be conceived of as a geological “event” rather than geological “epoch.” There are many deeply consequential phenomena to be found within geology’s description of the past that are nevertheless not formally declared within the GTS but considered as geological events. Ellis and company note the Great Oxygenation Event, the Great Ordovician Biodiversity Event, and the Devonian vascular plant conquest of land as key examples.

But what Kolbert, Rockström, and other “Anthropocene partisans” miss is that recognizing the Anthropocene as event rather than epoch is, if anything, more radical in its reckoning with Homo sapiens’ relationship to the rest of nature.

Recognizing the Anthropocene as a geological event prompts a philosophical-scientific framework that transcends mere comprehension of the profundity of what we have wrought to truly reckon with the deep-time novelty of what we are.

Evolutionary-Ecological Novelty

We can recognize this profundity when we consider the suggested comparisons. For example, the Great Oxygenation Event is believed to have resulted in the first and one of the most extreme mass extinction events. This extermination was compounded by a snowball Earth event—a global glaciation—that the oxygenation also likely caused. The deep freeze even threatened the cyanobacteria themselves, the very organisms that catalysed the event. Geochemists estimate that there was over an 80 percent collapse in the size of the biosphere. But, as time went on, the event produced something of an energetic quantum leap for life. The metabolism of oxygen is something of a superpower that allows organisms to do much more work. This energetic revolution, in turn, permitted the emergence of multicellularity.

At base, the late Devonian novelty is the vascularization of plants—the development of true roots, stems, branches and leaves, which resulted in break-up of rocks by roots, the first soils, and, as a result, a flood of nutrient “pollution” washing into the oceans. This nutrient flood into the oceans resulted in large algal blooms that triggered the Late Devonian mass extinction. These pulses of die-off amounted to a loss of perhaps three quarters of species. But had this event not occurred, there would be no lush, green terrestrial ecosystems that we humans love and depend on.

These two events were caused by life—novelties within the evolution of bacteria and then plants. Meanwhile, the likely cause of the Cambrian-Ordovician extinction, and thence the Great Ordovician Biodiversity Event—the third comparator of Ellis et al—was abiotic. It was an episode of massive volcanism that geologists call a large igneous province, a gargantuan effusion of lava flows across hundreds of thousands of kilometres. This released vast quantities of greenhouse gases and changed the climate. Collectively these selection pressures drove the emergence of radically more complex food webs, an increase in predator diversity, and much more competition for resources. A vastly more interesting world.

From a non-anthropocentric point of view, these events have no moral valence. They are neither good nor bad. They are simply the latest ecological transformation to occur in response to novel evolutionary selection pressures. However, from an anthropocentric point of view, we are very glad these novel selection pressures emerged, for we would not be here without them

But, if the Anthropocene is a geological event on the scale of these others and not a mere geological epoch, then what really is the Anthropocene Event? What fundamentally is the evolutionary-ecological novelty? In other words, what is its novel evolutionary selection pressure, and how do ecosystems respond? And, crucially, what ethical consequences follow from this?

In trying to pigeonhole the Anthropocene as a geological epoch, various scholars have suggested the cause, i.e., the novelty, was the Industrial Revolution, or the advent of the use of fossil fuels, or, as ultimately became the consensus of many in the AWG, the Great Acceleration (the radical uptick in human energetic and material consumptions after the Second World War). Some quarters of social science and political theory have tried to argue the novelty is political-economic: modernity, capitalism, the Enlightenment, etc. Journalist Naomi Klein argues that the ultimate cause was the scientific revolution’s Baconian impulse to dominate the rest of nature.

Meanwhile, as mentioned, advocates of the Anthropocene-as-event want us to recognize that developments such as the advent of cities, agriculture and even fire push radical human impacts much further back than the last few hundred years.

But no matter which of these options anyone might be sympathetic to for the Anthropocene’s origin story, the time-transgressive nature of them all suggests that they are all mere social epiphenomena atop a deeper evolutionary-ecological novelty.

If the Great Oxygenation Event’s evolutionary-ecological novelty is ultimately the advent of photosynthesis, and the late Devonian event’s novelty is the advent of plant vascularisation, then it follows that the evolutionary-ecological novelty of the Anthropocene Event is the advent of the advanced sapience of the genus Homo, particularly in the Homo sapiens lineage (but not exclusively).

This advanced sapience was sufficient to produce the first few species with dual inheritance—two lines of inherited information: genetic inheritance and cultural inheritance. Cultural inheritance, amongst other things, allows us to steadily improve technologies (including social technologies), resulting in a capacity to constantly change      our ecological niche construction far faster than genetic inheritance alone.

Put another way, the novelty is constant novelty.

And what is a possible evolutionary-ecological response to this constant novelty, akin to the explosion of multicellularity thanks to the Great Oxygenation Event, and the vertebrate colonization of land thanks to the Late Devonian event? What might be the ecological revolution this time? Potentially, a radiation of species (i.e. an explosion of new species) that are best able to flourish amidst constant novelty, to thrive in constantly changing conditions. This could include those that are highly adaptable and resilient, such as antibiotic resistant bacteria, raccoons, pigeons, rats, weedy plants and other denizens of regularly anthropically altered ecosystems. Science writer David Quammen, albeit disparagingly, has referred to this phenomenon as the “planet of weeds.”

From a non-anthropocentric, non-speciesist point of view, there is no more a moral valence to this future weedy ecological revolution than there is to the ecological revolutions that followed those other geological events of deep time. If, as anti-speciesism commands, all species have an equal right to existence, and simultaneously we cannot put an end to evolution, then the assemblage of species prior to any of these geological events is neither better nor worse than the assemblage of species following these events.

We do not say that cyanobacteria, vascular plants, or large igneous provinces were “destroying the planet” or “disrupting Earth systems.” The transformations they wrought were just the latest evolutionary selection pressures, and there is no direction or purpose to evolution. There is no optimum temperature for the planet; no optimum chemical composition of the atmosphere; no optimum pH or oxygen level to the oceans. Whatever set of conditions that exist on the earth—out to the theorized edge of the “Goldilocks Zone” for life in the solar system—there will be an assemblage of species that thrives, and an assemblage for which those same conditions are deadly. So, something like “multi-species flourishing”—i.e., the simultaneous flourishing of all species—is unworkable because there is no one set of conditions optimal for all species at the same time. And the optimum set of conditions for maximizing biological productivity, or species biodiversity or genetic biodiversity, may be different from the optimum set of conditions for human flourishing. We would have to ask instead “which set of species do we want to flourish?” And “what sort of biological productivity do we want?” But these questions unravel the supposed imperative to avoid speciesism.

So, let us now consider an explicitly and consciously anthropocentric and speciesist point of view to see if anything changes morally.

The immediate, obvious problem with our Anthropic ecological revolution is that not all these planet-of-weeds species may be the ones that deliver the ecosystem services we humans depend upon, and not all the ecological conditions that emerge from some of our technologies (such as global warming, nitrogen pollution, or, previously, ozone layer depletion, acid rain, lead pollution and so on) are amenable to us and the other species that we care most about. Just as cyanobacteria’s advent of photosynthesis almost wiped out cyanobacteria through that first Snowball Earth, so could our sapience wipe ourselves out.

Or, more likely and more prosaically, we could accidentally produce sub-optimal conditions that limit our flourishing. Our inadvertent changing of the climate is an example of this—harmful but most likely not existential.

Moreover, if the Anthropocene Event’s evolutionary-ecological novelty is our sapience, dual inheritance, and constant novelty, then we cannot undo that outside of our own extinction. In other words, we cannot retreat from the Anthropocene Event. It would require retreating further back than the emergence of Homo sapiens.

So we have no choice but to try to make the Anthropocene Event a good one—a “Good Anthropocene Event;” we cannot avoid our imposition of constant novelty. It is what we are.

Luckily, while cynanobacteria were solely driven by genetic inheritance and so could do no other than continue producing free oxygen, our sapience and thus cultural inheritance enable us to adapt by switching technologies when we discover that one of them (including social technologies) is harmful to us. We can, in principle, through decoupling of economic development from negative environmental impacts, ensure that the evolutionary-ecological novelty of constant novelty does not deteriorate the ecosystem services that we and the species we care most about depend upon.

What are the ethical consequences of all this? This means that we need to be more cognizant of our radical evolutionary-ecological novelty, which is at least as profound as the advent of photosynthesis and use it to tend and alter the earth’s garden consciously. We must deliberately shape the earth system in our interest, rather than accidentally altering it in ways that potentially harm us.

But be very clear, this also means that to mitigate climate change, to bring an end to nitrogen pollution, to avoid biodiversity loss, and all the other environmental measures we rightly undertake, cannot mean that we do it to “save the planet,” to “liberate nature,”, or to “restore a healthy planet.” None of this makes any sense now. Environmental action can instead only, logically, be to “save” ourselves and those other species we most care about. Or, more accurately and less apocalyptically, environmental action can only be to optimize conditions for ourselves (and, again, the organisms we like most based on how closely they approach us in our situation as moral agents).

Recognition of the Anthropocene as event unavoidably entails an explicitly humanist environmentalism. And that humanism may make some a bit uncomfortable because it suggests that some species are more important than others. But it is the only response to environmental challenges that is coherent with a deep-time understanding of what the evolutionary-ecological novelty of humanity truly is.

It is the only response that plumbs the full scientific and moral depth of the Anthropocene.