For years, one question has sparked a debate between geologists and environmentalists: have human beings measurably/permanently altered the planet?
If you've been following the news this week, there's been a flutter of excitement — scientists may have found definitive proof of humanity's industrious (pun intended) life on Earth. We might be living in the Anthropocene!
Yet unlike most news features, I don't want to dive headlong into the proof, just yet. I'd like to take a longer view of what the Anthropocene means, and why it is an important debate in academic and advocacy circles.
The Anthropocene — a proposed but still-to-be-formally-accepted term, derived from the Greek roots 'anthros' for human and 'kainos' meaning ‘new’ — represents the epoch when human activity begins to leave an indelible, irrefutable mark on the planet.
Though it was popularised by atmospheric chemist Paul J. Crutzen in 2000, geologists have been slow to define and accept it. Yet literature and popular culture have jumped on the bandwagon, with many peer-reviewed articles, novels, and music tracks bearing the term, Anthropocene, and online dictionaries publishing definitions too.
THE RACE TO FIND SIGNATURES OF HUMAN ACTIVITY
For over a decade, teams of scientists under the aegis of the Anthropocene Working Group, have been collecting core samples from rocks, sediments and ice across 11 locations, and 5 continents, in search of signatures of human activity. Excitingly, this race was both a collaboration and a competition, as ultimately only one site of eleven sites will bear the title of the "golden spike" location for the Anthropocene — and will represent the very boundary between past and present, between nature and human dominance, etched indelibly in the geological record.
Previous epochs were also defined by distinct boundaries in the geological record; an ice core from Antarctica bears a line of pollen and dust and serves as the official reference point for the start of the Holocene epoch, which began at the end of the last Ice Age, approximately 12,000 years ago. The age of the dinosaurs ended about 66 million years ago, as the debris records from the meteor impact in a Tunisian cliff attest.
So what comprises a signature? Materials which can be attributed to human industrial activity and do not occur naturally in the environment, and more importantly, are preserved in the geological record. Such industrial materials could include concentrations of mercury or lead pollution, heavy metals, fly ash, nuclear debris from the atomic age, isotopes in the rocks, trees, atmosphere, or humans, and plastics, especially microplastics. These signatures will help researchers identify the telltale, dramatic spike in human activity — a period known as 'The Great Acceleration'.
CRAWFORD LAKE, CANADA - THE GOLDEN SPIKE SITE?
At a press conference on July 11, 2023, Earth Science professor, Francine McCarthy, who led the working group of scientists studying Canada's Crawford Lake, proposed it as a golden spike site for the Anthropocene.
Crawford Lake was formed after a limestone cave collapsed and waters filled in the deep hole. In summer, as with most limestone lakes, the heat causes calcium carbonate to precipitate and sink to the bottom - a layered chalky record of the passage of time. Its depth ensures that the bottom-most layer of water does not mix as much with the upper layers, and the sediment can lie undisturbed on its bed.
Among these sediment layers, fly ash specks which serve as evidence of fossil fuel burning and traces of radioactive plutonium — chemical traces of the fallout from nuclear bombs — bolster Crawford Lake's claim as a reference point for the Anthropocene. Based on their findings, the team has proposed two possible dates for the golden spike: 1950, marked by accelerated environmental changes, or 1952, when there was a significant rise in plutonium levels. The proposal needs to go through a couple of rounds of approvals before a verdict is reached.
Interestingly, Crawford Lake has been granted the right of personhood by the indigenous communities that inhabit the area. As further sample collection may violate this status, McCarthy's research group will have to hang up their (hard) hats. In the meantime, the race continues at other research sites. If Crawford Lake fails to make the cut, other researchers will try to ascertain the golden spike location and proffer evidence for humanity's cataclysmic impact on the planet.
A SIDE QUEST: DECOLONISING THE ANTHROPOCENE
While reading up on this topic, I found myself in an interesting rabbit hole. A paper in a journal of critical geographies argued that linking the Anthropocene to colonization is crucial in understanding the ecological crisis we face today. By recognizing colonization as its starting point, and more specifically 1610, we can challenge the notion of inevitability and highlight the violence and power dynamics at its core. It calls for incorporating indigenous knowledge and self-governance while recognising the current ecological state as a product of specific ideologies rooted in extraction and accumulation through dispossession.
THE ANTHROPOCENE & CLIMATE CHANGE
Why is defining the Anthropocene so crucial? Some believe that the Anthropocene could represent the first time in Earth's history when a single species has not only radically changed the planet's physical, chemical, and biological constitution, but is acutely aware of having done so. A few others disagree about humanity's impact on the environment — an argument we hear often in climate change conversations — and resist the very idea of defining a new epoch.
Conversations around the Anthropocene also bring the issue of climate change into sharp focus, especially, as the world is facing extreme weather events in the recent past. Beyond signatures that are preserved in the geological record, humanity's marked impact on the planet is evident in the heat waves, flooding events, intense droughts, increased forest fires, polar vortexes, erratic patterns of precipitation, and the list goes on. This interactive CarbonBrief map depicts 'extreme events', as reported in peer-reviewed scientific publications, and offers mounting evidence of the role of human activity in exacerbating these risks and tipping over the fine balance of the Earth.
Over the years, climate change news has triggered the biggest epidemic of all: apathy. As a final note, I'd like to offer a perspective from human history: delineating, and defining the Anthropocene epoch will allow us to reflect more broadly on the planet's geologic history, and consider humanity's role in it, as well as questions of human accountability, responsibility, and morality.