When people talk about the “Anthropocene,” they often picture the massive impact human societies are having on the planet, from rapid declines in biodiversity to rising Earth temperatures through the burning of fossil fuels.
Planetary changes of this magnitude did not begin suddenly in any place or time.
It was therefore 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 a period starting exactly from 1952 on the geological time scale. The sign was radioactive fallout. From hydrogen bomb tests.
On March 4, 2024, the commission responsible for recognizing units of time within the most recent period of our geological time – the Subcommittee on Quaternary Stratigraphy – rejected this proposal, with 12 of 18 members voting no. These are the scientists most expert at reconstructing Earth’s history from evidence in rocks. They determined 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 nothing to do with the overwhelming evidence that human societies are indeed transforming this planet.
As an ecologist studying 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 too narrowly to undermine broader scientific and public understanding.
By tying the beginning of the human age to such a new and devastating event – nuclear fallout – the proposal risked creating confusion about the deep history of how humans have transformed the Earth, from climate change and biodiversity losses to plastic pollution and tropical 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-caused planetary transformation, from climate change to biodiversity loss, plastic pollution, megafires, and more. More.
Crutzen initially proposed that the Anthropocene began in the second half of the 18th century as a product of the Industrial age. He also stated 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 influencing Earth’s biodiversity and climate through agriculture thousands of years ago. These changes began to accelerate with the colonial collision of the old and new worlds about five centuries ago. And as Crutzen points out, Earth’s climate really began to change with the increased use of fossil fuels in the Industrial Revolution, which began in the late 1700s.
Anthropocene as an epoch
The rationale for proposing to define an Anthropocene Epoch that began around 1950 came from overwhelming evidence that many of the most significant changes in human history shifted dramatically upward during that period, the so-called “Great Acceleration” described by climate scientist Will Steffen and others. .
Radioisotopes such as plutonium from hydrogen bomb tests conducted during this period left clear traces in soil, sediments, trees, corals, and other potential geological records across the planet. Selected as the “golden nail” for marking the beginning of the Anthropocene Epoch, the plutonium peak in the sediments of Crawford Lake in Ontario, Canada, is clearly marked in the lake bed’s exceptionally clear sediment record.
The Anthropocene Era is dead; long live the Anthropocene
So why was the Anthropocene Era rejected? Alright what now?
The proposal to add an Anthropocene Epoch to the geological time scale was rejected for various reasons; None of this was about the fact that human societies are changing this planet. In fact, the opposite is true.
If there is one main reason why geologists reject this proposal, it is that recent history and shallow depth are too narrow to encompass deeper evidence of human-caused planetary change. As geologist Bill Ruddiman and others wrote in Science Magazine in 2015, “Does it really make sense to define the beginning of an era of human domination a thousand years after most of the forests in arable regions were cleared for agriculture?”
The debate about the Anthropocene Epoch is not over yet. However, the rulebook for determining units of the geological time scale requires that approved periods cannot be changed for at least 10 years, so an official Anthropocene Epoch declaration is unlikely any time soon.
The lack of an official definition of the Anthropocene Epoch will not pose a problem for science.
A scientific definition of the Anthropocene is already widely available in the form of the Anthropocene Event; This essentially defines the Anthropocene in simple geological terms as “a complex, transformative, and ongoing event similar to the Great Oxidation Event and others in the geological record.”
Thus, despite the “no” vote on the Anthropocene Epoch, the Anthropocene will continue to be as useful in stimulating debate and research on the nature of human transformation of this planet as it has been for over 20 years.
This article is republished from The Conversation, an independent, nonprofit news organization providing facts and authoritative analysis to help you understand our complex world. 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 Association of American Geographers.