When people talk about the “Anthropocene,” they typically imagine the enormous impact human societies are having on the planet, from rapid declines in biodiversity to increases in global temperatures from burning fossil fuels.
Such massive planetary changes did not all begin at one time or place.
That’s why it was controversial when, after more than a decade of study and debate, an international committee of scientists – the Anthropocene Working Group – proposed marking the Anthropocene as an epoch on the geological time scale that began precisely in 1952. of hydrogen bomb tests.
On March 4, 2024, the committee responsible for recognizing time units within our most recent period of geologic time – the Subcommittee on Quaternary Stratigraphy – rejected that proposal, with 12 of 18 members voting against. These are the scientists most expert at reconstructing Earth’s history from evidence in rocks. They found that adding an Anthropocene epoch – and ending the Holocene epoch – was not supported by the standards used to define epochs.
To be clear, this vote has no bearing on the overwhelming evidence that human societies are indeed transforming this planet.
As an ecologist who studies changes in the world, I have been part of the Anthropocene Working Group from its inception in 2009 until 2023. I resigned because I was convinced that this proposal defined the Anthropocene so narrowly that it would damage broader scientific and public understanding.
By linking the dawn of the human era to such a recent and devastating event – nuclear fallout – this proposal risked confusing the deep history of how humans are transforming the Earth, from climate change and biodiversity loss to plastic and tropical pollution. deforestation.
The original idea of the Anthropocene
In the years since the term Anthropocene was coined by Nobel Prize-winning atmospheric chemist Paul Crutzen in 2000, it has increasingly defined our time as an era of human-induced planetary transformation, from climate change to biodiversity loss, plastic pollution, megafires and more. much more. more.
Crutzen originally proposed that the Anthropocene began in the latter part of the 18th century, as a product of the Industrial Age. He also noted that setting a more precise start date would be “arbitrary.”
According to geologists, we humans have been living in the Holocene for about 11,700 years, since the end of the last ice age.
Human societies began influencing Earth’s biodiversity and climate through agriculture thousands of years ago. These changes began to accelerate about five centuries ago with the colonial collision of the old and new worlds. And, as Crutzen noted, Earth’s climate really began to change with the increasing use of fossil fuels during the Industrial Revolution that began in the late 1700s.
The Anthropocene as an era
The rationale for the proposal to define an Anthropocene epoch beginning around 1950 arose from overwhelming evidence that many of the most consequential changes of the human epoch shifted dramatically upwards around that time in a so-called ‘Great Acceleration’ , identified by climate scientist Will Steffen and others. .
Radioisotopes such as plutonium from hydrogen bomb tests conducted around this time left clear traces in soils, sediments, trees, corals and other potential geological records across the planet. The plutonium peak in the sediments of Crawford Lake in Ontario, Canada – chosen as the “golden peak” to define the beginning of the Anthropocene epoch – is well marked in the exceptionally clear lakebed sediment record.
The Anthropocene Epoch is dead; long live the Anthropocene
So why was the Anthropocene era rejected? And what happens now?
The proposal to add an Anthropocene epoch to the geological time scale was rejected for several reasons, none of which were related to the fact that human societies are changing this planet. In fact, the opposite is true.
If there is one major reason why geologists have rejected this proposal, it is because its recent dating and shallow depth are too limited to encompass the deeper evidence of human-induced planetary changes. As geologist Bill Ruddiman and others wrote in Science Magazine in 2015, “Does it really make sense to define the beginning of a human-dominated era, millennia after most cropland forests had been cleared for agriculture?”
The discussions about an Anthropocene era are not over yet. But the rulebook for determining units of the geologic time scale requires that ratified epochs cannot be changed for at least ten years, so it’s highly unlikely that an official Anthropocene epoch declaration will happen anytime soon.
The lack of a formal definition of an Anthropocene epoch will not be a problem for science.
A scientific definition of the Anthropocene is already widely available in the form of the Anthropocene Event, which essentially defines the Anthropocene in simple geological terms as “a complex, transformative and ongoing event analogous to the Great Oxidation Event and others in geological history.”
So despite the “no” vote on the Anthropocene, the Anthropocene will remain as useful as it has been for more than twenty years in stimulating discussion and research into the nature of human transformation of this planet.
This article is republished from The Conversation, an independent nonprofit organization providing facts and trusted analysis to help you understand our complex world. It was written by: Erle C. Ellis, University of Maryland, Baltimore County
Read more:
Erle C. Ellis is a former member of the Anthropocene Working Group of the International Commission on Stratigraphy. He is a member of the American Association of Geographers.