The move signals the end of the Holocene epoch, which began 12,000 to 11,600 years ago
Rising global temperatures, sea levels, depleting ozone layer and acidifying oceans are the result of human activity that has “distinctively” altered our planet. Now, a team of scientists have voted to declare “Anthropocene” as a new chapter in the Earth’s geological history.
Coined by Paul Crutzen and Eugene Stoermer in 2000 to denote the present geological time interval, Anthropocene has been used to describe humanity’s large impact on the environment, but the scientific community has in the past years intensely debated the idea to formally define it as a geological unit within the Geological Time Scale.
On May 21, 2019, 29 of the 34-member Anthropocene Working Group (AWG), voted in favour of starting the new epoch. The result builds on an informal vote taken at the 2016 International Geological Congress in Cape Town, and lays the groundwork for a formal proposal by 2021 to the International Commission on Stratigraphy.
“The Anthropocene works as a geological unit of time, process and strata,” Jan Zalasiewicz, chair of the AWG and a geologist at the University of Leicester, UK, said in an article published in the Nature journal. The Anthropocene, according to Zalasiewicz is “distinguishable...distinctive”.
The move signals the end of the Holocene epoch, which began 12,000 to 11,600 years ago.
But, to show a clear transition from the Holocene, the scientists plan to identify a definitive geologic marker or ‘golden spike’, and would be technically called a Global boundary Stratotype Section and Point (GSSP). For this, the group will search for the marker from around the globe, including a cave in northern Italy, corals in the Great Barrier Reef and a lake in China.
To demonstrate a sedimentary record representing the start of the epoch, the team is likely to choose the radionuclides that came from atomic-bomb detonations from 1945 until the Limited Nuclear Test Ban Treaty of 1963, Zalasiewicz said.
The International Union of Geological Sciences needs to ratify the AWG formal proposal, before the new epoch can formally be recognised.
Objecting against a single clear signal in the geological record, four members of the AWG voted against the idea of designating the Anthropocene as a new epoch.
“The stratigraphic evidence overwhelmingly indicates a time-transgressive Anthropocene with multiple beginnings rather than a single moment of origin,” says Matt Edgeworth, an archaeologist at the University of Leicester, UK, and a member of the AWG.
Declaring a new epoch on the basis of the radionuclide signal alone, “impedes rather than facilitates scientific understanding of human involvement in Earth system change”, Edgeworth said.
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