Anthropocene may officially become a geological age – 07/11/2023 – Fundamental Science

A revolution is simmering in the world of geology. And an announcement from Tuesday, July 11th, has just increased the intensity of the flame: researchers from the Anthropocene Working Group (AWG) have chosen a geological landmark to demonstrate the advent of the “Epoch of Humans”. “, or Anthropocene.

In practice, it is a breakthrough in deciding whether or not the Anthropocene should enter the geological time scale that officially demarcates eras, periods, epochs and other intervals of the Earth’s age as we know it.

From a list of 12 geological sites that could prove the emergence of the new epoch, researchers from the AWG chose Lake Crawford — located in a nature reserve in southern Ontario, Canada — as the physical representative of the change.

Based on samples collected in 2019 and 2022, a group of researchers made an important discovery: the waters at the bottom of that lake contained oxygen. According to palaeoclimatologist Francine McCarthy — a researcher at Brock University, in Canada, and coordinator of studies at the site — finding oxygen there was important because, thus, the rock layers on the lake bed “managed to record, very clearly, traces of plutonium released in the detonation of nuclear bombs in the early 1950s” — a timeframe proposed as a starting point for the Anthropocene.

To carve a new milestone in geological chronology, scientists must first collect several rock samples — and they need to mirror a major change that has happened simultaneously on a global scale. In the case of the Anthropocene, the explosion of hydrogen bombs could be that big event, as no continent escaped the radioactivity of these explosions.

Once the most significant sample has been chosen, the discussion moves on to a higher level. Now the AWG proposal needs to be approved by the International Union of Geological Sciences, at which point the nomenclature will become official. “The requirement to go through three levels of voting forces the proposal to be very solid. It’s a very conservative process, and there’s a reason for that: you can’t formalize a unit [estratigráfica] without the support of robust evidence,” says geologist Colin Waters, coordinator of the AWG.

Popularized in 2000 by biologist Eugene Stoermer and Nobel Prize in Chemistry Paul Crutzen, the term Anthropocene derives from the Greek — combination of anthropos (human) and scene (new) — and names a new geological division, in which human activities have had a decisive impact on environmental change. Thus, the Earth leaves behind the Holocene, which began at the end of the last glaciation, around 11,700 years ago.

It was in the Holocene that humanity achieved its greatest advances, from the creation of agricultural systems to progress in politics and economics, including the emergence of writing and science. “As the climate in the Holocene remained extraordinarily stable, Europe, especially in the Renaissance, had the luxury of creating a philosophy that did not take nature into account, as if only the relationship between humans was decisive,” says Renzo Taddei, professor of Anthropology at the Federal University of São Paulo (Unifesp).

That is why Taddei, who has been working on the subject for almost two decades, considers the Anthropocene a dramatic “turn of the key”, since it gives protagonism to nature in the sphere of human thought. “The Anthropocene shows us that the Renaissance optimism regarding technique, the domination of nature and later industrial capitalism was an illusion”, he adds.

For the physicist and historian of science Jürgen Renn, director of the Max Planck Institute for the History of Science in Berlin, one of the great challenges that the possible new era proposes is to make “a geology of the present”: to open a new chapter in the geological book as we witness the writing of this new page — or stratigraphic layer. Furthermore, due to the philosophical questions and questions it raises, the new era “creates a bridge between the natural sciences and the humanities”.

Taddei observes that, while geology decides whether to formalize the term or not, disciplines such as philosophy and anthropology itself adopted it immediately. The concept isn’t perfect, he says, “but it manages to encapsulate our dysfunctional relationship with the planet in multiple dimensions.” Not because we became aware that reflection was necessary, but because nature imposed it, with its altered balance and increasingly frequent and intense extreme events.

“The Anthropocene caught us unawares. I see this era as a huge ‘slap in the face’ of modern Western arrogance, which effectively thought it was solving all historical problems,” concludes the anthropologist.

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Meghie Rodrigues is a science journalist.

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