by When people talk about the “Anthropocene,” they usually refer to the enormous impact human societies have had on the planet, from the rapid decline of biodiversity to increases in Earth’s temperature through the burning of fossil fuels.
Such massive planetary changes did not all begin at once in one place or time.
That is why it was controversial when an international committee of scientists – the Anthropocene Working Group – after more than ten years of study and debate – proposed to mark the Anthropocene as an epoch in the geological time scale starting precisely in 1952. A radioactive fallout that was in the marker. from hydrogen bomb tests.
On March 4, 2024, the Commission responsible for identifying time units within our most recent geological time period – the Sub-Commission on the Quarterly Strategy – rejected that proposal, and 12 out of 18 members voted no. These are the scientists who are most expert in reconstructing the history of the Earth from the evidence in rocks. They concluded that the standards used to define periods did not support the addition of the Anthropocene Era – and the elimination of the Holocaust Era.
To be clear, this vote has no bearing on the overwhelming evidence that human societies are transforming this planet.
As an ecologist who studies global change, I served on 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 detrimental to wider scientific and public understanding.
By tying the beginning of the human age to such a recent catastrophic event – nuclear fallout – this proposal confused the deep history of how humans are transforming the Earth, from climate change and biodiversity loss to plastic pollution and tropical deforestation.
The basic idea of the Anthropocene
In the years since the term Anthropocene was coined by atmospheric chemist Paul Crutzen who won the Nobel Prize in 2000, it has increasingly defined our times as an age of human-caused planetary transformation, from climate change to biodiversity loss, pollution plastic, megawatt fires and many. bigger.
Crutzen first 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 Epoch for about 11,700 years, since the end of the last ice age.
Human societies began to affect Earth’s biodiversity and climate through agriculture thousands of years ago. These changes began to intensify about five hundred years ago with the colonial collision of the old world and the new world. And, as Crutzen noted, the Earth’s climate really began to change when the use of fossil fuels increased in the Industrial Revolution that began in the late 1700s.
The Anthropocene as an epoch
The rationale for defining the Anthropocene Era as beginning around 1950 came from overwhelming evidence that many of the most consequential changes in the human age by that time had greatly increased in a so-called “Great Acceleration” identified by the -climate scientist Will Steffen and others. .
Radioisotopes like plutonium from hydrogen bomb tests conducted around this time left clear traces in soils, sediments, trees, corals and other possible geological records across the planet. The plutonium peak in the sediments of Crawford Lake in Ontario, Canada – chosen as the “golden spike” to determine the beginning of the Anthropocene Age – is well marked in the exceptionally clear sedimentary record of the lake bed.
The Anthropocene Age is dead; Long live the Anthropocene
So why was the Anthropocene Era rejected? And what happens now?
The proposal to add the Anthropocene Era to the geological time scale was rejected for a variety of reasons, none of which related to the fact that human societies are changing this planet. In fact, the opposite is true.
If there is one main reason geologists have rejected this proposal, it is because its recent date and shallow depth are too narrow to contain deeper evidence of human-induced planetary change. As geologist Bill Ruddiman and others wrote in Science Magazine in 2015, “Does it really make sense to define the beginning of a millennium as a human-dominated era after most forests in arable regions have been cleared for agriculture? “
The discussions on the Anthropocene Age are not over yet. But the rulebook for determining units of the geologic time scale requires that fixed periods cannot be changed for at least 10 years, so an official declaration of the Anthropocene Era is unlikely anytime soon.
The lack of a formal definition of the Anthropocene is not a problem for science.
A scientific definition of the Anthropocene is already widely available in the form of the Anthropocene Event, which basically defines the Anthropocene in simple geological terms as “a complex, transformative and ongoing event on par with the Great Oxidation Event and others in the geological record.”
So, despite the “no” vote on the Anthropocene Era, the Anthropocene will continue to be as useful as it has been for more than 20 years to stimulate discussion and research on the nature of human transformation of this planet.
This article is republished from The Conversation, a non-profit, independent news organization that brings you reliable facts and analysis to help you make sense of our complex world. It was written by: Erle C. Ellis, University of Maryland, Baltimore County
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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.
