Anthropocene Revoked: The proposal to formalize a new epoch was just rejected — what now?
“…Shovel them under and let me work. Two years, ten years, and passengers ask the conductor:
What place is this? Where are we now?
I am the grass. Let me work.” — Grass by Carl Sandburg
A 15-year journey came to an end on March 4th, as the International Union of Geological Sciences rejected the Anthropocene as a new epoch.
Stratigraphy is a branch of geology revolving around our sense of time. Deep time. The kind of time that attempts to date the Earth beyond human history, beyond dinosaurs, and beyond any documented form of life at all — back to the Earth’s formation.
Experts in stratigraphy — which stems from the root word “stratum”, meaning “layer of rock” — developed this sense of “geological time” using the planet’s rock record to divide events in Earth’s history into groups. These units of time, from largest to smallest, include eons, eras, periods, epochs, and ages. These units serve the practical function of allowing us to understand when certain life forms came to be, when they became extinct, when major climactic changes occurred and why, etc.
However, they also serve the dual function of helping human beings understand their position and impact on our old and vast planet. As illustrated in the above diagram, when we consider geological time, humans have been around for less than a blink of an eye.
The Earth is estimated to be around 4.5 billion-years-old. Our species is estimated to be approximately 300,000-years-old. This means that we occupy only 0.007% of the Earth’s history. And yet, our impact has been immense.
We have destroyed over one-third of global forests, their oxygen-generating leaves returning to dust, their soil-stabilizing roots torn from the ground.
We’ve reduced the amount of wild grass and shrubland by a nearly equal percentage. The stable biodiversity of these ecosystems has been, in large part, replaced by agricultural monocultures that frequently require large amounts of herbicides and pesticides to persist and meet production demands.
Large areas have also been paved with concrete and built up with residential, commercial, and industrial complexes that meet key human needs and wants but fail to provide any of the ecological benefits of a natural system.
We’ve also taken to mining, whether by stripping the earth of its surface or hollowing it out underground, to source raw materials for use in chemical synthesis and manufacturing. Then, there’s overfishing and pollution, the creation of “forever chemicals”, fossil fuel consumption and greenhouse gas emissions, pollution of oceans, lakes, and groundwater reserves, and many other — largely gloomy — human impacts on the world.
This leads us to the Anthropocene debate. Our impacts are clear. But has the impact been large enough to justify a new epoch? Until the early 2000s, our geological clock ended with the Holocene, which we defined as beginning over 11,000-years-ago when the last ice age ended.
The Anthropocene would be the beginning of a new epoch, one defined primarily by human impacts on the planet. You’ll remember that climate is a large portion of how a unit of geological time is defined, as the geological record can reveal everything from wind patterns and volcanic eruptions to the composition of the atmosphere at a given time. The proposal to formally define this human-influenced time as an epoch was rejected earlier this month.
Have we just not made enough of an impact to have started a new geological unit? Was the decision based on a lack of evidence or our current methods of stratigraphy? Did deep-time politics have anything to do with the decision?
The Anthropocene is a well-loved term. It sounds wonderful and important and true in its centering of the human enterprise on impacts on the environment. But in terms of geological time, ‘chronostratigraphic’ evidence had to be gathered. That means, geologists had to find physical sites where rock layers showed clear changes from one unit to another.
It wasn’t until 2023, that a group of scientists promoting the found a record they thought was undisturbed enough to verify that a new geological time had truly begun.
The evidence was found in the sediments of Crawford Lake in Ontario, which held markers of environmental degradation, fertilizer use, and even plutonium isotopes from nuclear weaponry. That meant that the beginning of the Anthropocene, based on this unit, coincided with the creation of the hydrogen bomb, the onset of the Korean War, and the civil rights movement in the United States. Therefore, at least according to the resulting proposal, the Anthropocene began in the 1950s.
However, this new evidence only raised more questions among researchers. The Holocene recursively defines over 11,000 years of the Earth’s history. Can we truly define an epoch in real time, only 75 years in? And can we truly pinpoint the 1950s as the beginning of this time period when massive greenhouse gas impacts began over 50 years prior?
These questions were all points of contention, even among the Anthropocene Working Group (AWG), which developed and voted on the proposal. These issues became so contentious that a long-involved group member, and current director of the Anthroecology Lab, resigned from the group.
The member, Erle Ellis, cited: “the increasingly corrosive nature of discussions surrounding two recent resignations,” and concerns over the narrow definition of Anthropocene as key reasons for the decision. Ellis’s full resignation letter is published here.
Elaborating in the letter, Ellis wrote:
“The AWG’s choice to systematically ignore overwhelming evidence of Earth’s long-term anthropogenic transformation is not just bad science, it’s bad for public understanding and action on global change. This, at a time when broader cooperation to address these grave societal challenges is more critical than ever.”
Ellis also expressed concern regarding the social and political ramifications of such a narrow definition, writing:
“To define the Anthropocene as a shallow band of sediment in a single lake is an esoteric academic matter. But dividing Earth’s human transformation into two parts, pre- and post-1950, does real damage by denying the deeper history and the ultimate causes of Earth’s unfolding social-environmental crisis. Are the planetary changes wrought by industrial and colonial nations before 1950 not significant enough to transform the planet? The political ramifications of such a misleading and scientifically inaccurate portrayal are clearly profound and regressive.”
Ellis argued that the finding would not be confined to world of stratigraphy, and could easily be misinterpreted by media outlets and the public at large.
This point may be supported by the observation that the term Anthropocene has been used in popular culture, and embraced by writers, musicians, and some scientists, since long before the golden stratigraphic evidence was collected at Crawford Lake in 2023. Ultimately, despite this evidence, the Anthropocene did not win the vote of the Subcommission on Quaternary Stratigraphy.
Due to some members ‘aging-out’ of voting status, and what some described as a rushed voting process, the vote was almost immediately contested. However, it was later upheld by the International Union of Geological Sciences.
So, given that this development does not only impact stratigraphers, what are the ramifications of the vote? In 2019, the Quarternary journal, published by the Multidisciplinary Digital Publishing Institute (MDPI), released a special issue pertaining to this exact question entitled, “What if the ‘Anthropocene’ is Not Formalized as a New Geological Epoch?”
Two articles were published, written by earth science researchers affiliated with institutes in Spain, Belgium, New Jersey, the UK, and Italy.
Authors Martin Bohle and Nic Bilham discussed potential geoethical considerations for the vote, citing the ‘geoethical promise’ as well as methodological rigor:
“Regarding the roles and responsibilities of geoscientists in the face of global change, the Cape Town Statement on Geoethics states: “Geoscientists have know-how that is essential to orientate societies towards more sustainable practices in our conscious interactions with the Earth system. Applying a wider knowledge-base than natural sciences, geoscientists need to take multidisciplinary approaches to economic and environmental problems, embracing (geo)ethical and social perspectives. Geoscientists are primarily at the service of society. This is the deeper purpose of their activity.””
The authors concluded, using this promise as a framework, that if the proposal was accepted it would not cause ethical issues. But if it was rejected, an “ethical quandary” would occur.
The authors argued that if the IUGS rejected the proposal because it did not meet established scientific methodologies, they would uphold the promise of methodological rigor but not the promise of considering social context.
Despite this, the authors pointed out that, “Geologists developed the geological time scale (International Chronostratigraphic Chart) to describe a distant past of millions or billions of years. Although the geological time scale includes the present, it is mainly about the history of Earth in deep time, driven by geological processes… Seen at that geological timescale, human history is an almost instantaneous event, more like a point than a period of time.”
They proposed that a possible remedy to balance potentially competing geoethical concerns could be the addition of a new ‘transition point’ category to the International Chronostratigraphic Chart to be situated in more recent history and to mark the beginning of a longer change to the geological record.
In a separate piece, author Valentí Rull similarly discussed different non-epoch categories that may be more appropriate for the observed anthropogenic changes and comply with current chronostratigraphic methodologies. They noted that the formalization of the term seemed to matter most in geological and stratigraphic circles.
Recounting an experience giving a talk at the Autonomous University of Madrid, where the audience was primarily comprised of professionals in social sciences, activism, and philosophy, Rull noted that many audience members simply felt that the term would continue to be used regardless of formalization and questioned the use of defining the term. Others argued that new terms could be used to describe changes to the environment outside of the chronostratigraphic paradigm.
In addition to a growing body of evidence supporting some kind of stratigraphic delineation, Rull pointed out that many geologists believed a formal definition of the Anthropocene might mobilize governments to enact corrective actions pertaining to the environment.
Rull ultimately argued, however, that while stratigraphic committees were not created to police the use of terms, “Anthropocene: was strictly stratigraphic and its formalization should be assessed through the lens of the field, not through the lens of social or political considerations.
It seems that with a growing understanding of the impacts human beings have on the environment, combined with the sheer allure of using an all-encompassing word like “Anthropocene” to describe the momentous and personal consequences of the human enterprise, complete disentanglement from social and philosophical implications may not be feasible.
However, the rejection of the proposal seems to place geologists and non-geologists at an unexpected crossroads. While geological scientists may no longer be able to refer to a post-Holocene epoch due to the current consensus, the term will continue to be used in the arts and social sciences as a definition for humanity’s spark at the end of geological time.
As Chris Thomas, head of the Leverhulme Centre for Anthropocene Biodiversity at the University of York, described in an interview with Nature Magazine, the term seems to appeal to many as a description of “indivisible connectedness.”
“It’s undoable ,” he said. “The change is everywhere.”
