Our planet, at least for the time being, remains firmly in the Holocene epoch which began 11,700 years ago with the most recent melting of the ice sheets, years of stable climate during which human civilisation arose.
The top body in geology, however, has overruled a contested vote by scientists in favour of locating our present as a new interval in the official geologic timeline of Earth’s history, the Anthropocene age of human-induced planetary-scale changes, of nuclear weapons, human-caused climate change and the proliferation of plastics, garbage and concrete across the planet.
The term, widely employed in other disciplines, will, however, continue to be used and the proposal is not dead. The suggestion to define our age as Anthropocene – overturned as inadequately based on evidence – came initially from a subcommittee of the International Union of Geological Sciences, the Anthropocene working group (AWG), which took an appropriately glacial 15 years to reach its recommendation.
The geologic time scale divides Earth’s 4.6 billion-year story into chapters, sub-chapters and sub-sub-chapters, from largest to smallest, eons, eras, periods, epochs and ages. Right now we are in the Meghalayan Age of the Holocene Epoch of the Quaternary Period of the Cenozoic Era of the Phanerozoic Eon.
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The AWG suggest that the Anthropocene started in 1952, when plutonium from hydrogen bomb tests showed up in the sediment of Crawford Lake near Toronto, Canada. That’s when, they argue, human populations, economic activity and greenhouse gas emissions began skyrocketing worldwide, leaving indelible traces.
But given the pace at which change comes, even the notion of a start date is problematic. When exactly does incremental, quantitative change become qualitative change? When does an age qualify as an epoch or a period? Why not start with the dawn of agriculture or the industrial revolution? Geologists, it seems, are stuck between a rock and a hard place.