Note4Students

From UPSC perspective, the following things are important :

Prelims level : Anthropocene epoch

Mains level : Geological time scale of Earth

• 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.

Anthropocene Epoch

• 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.
• The scientific community have intensely debated in the past the idea to formally define it as a geological unit within the Geological Time Scale.
• Recently 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 move signals the end of the Holocene epoch, which began 12,000 to 11,600 years ago.
• The International Union of Geological Sciences needs to ratify the AWG formal proposal, before the new epoch can formally be recognised.

Global boundary Stratotype Section and Point

• To show a clear transition from the Holocene, the scientists plan to identify a definitive geologic marker or ‘golden spike’.
• It 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.

Demarcation of an epoch is not so easy

• To demonstrate a sedimentary record representing the start of the epoch, the researchers are likely to choose the radionuclides that came from atomic-bomb detonations from 1945 until the Limited Nuclear Test Ban Treaty of 1963.
• The stratigraphic evidence indicates a time-transgressive Anthropocene with multiple beginnings rather than a single moment of origin.
• 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.