Scientists Are Arguing About When, Exactly, Humans Started to Rule the Planet
Mother Jones
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Signs of human impact on the planet are everywhere. Sea levels are rising as ice at both poles melts; plastic waste clogs the ocean; urban sprawl paves over landscapes while industrial agricultural empties aquifers. Between climate change, urban development, and straight-up, old-school pollution, the Earth we inhabit now would be scarcely recognizable to our earliest ancestors 150,000 year ago.
In fact, these changes are so pronounced and their connection to human activity so obvious, that many scientists now believe we’ve already ventured well past a remarkable tipping point—Homo sapiens, they argue, have now surpassed nature as the dominant force shaping the Earth’s landscapes, atmosphere, and other living things. Units of deep geologic time often are defined by their dominant species: 400 million years ago fish owned the Devonian Period; 265 million years ago dinosaurs ruled the Mesozoic Era. Today, humans dominate the Anthropocene.
If defining what the Anthropocene represents is straight-forward, assigning it a commencement date has proved a monumental challenge. The term was first proposed by Russian geologist Aleksei Pavlov in 1922, and since then it has occupied off-and-on the attentions of the niche group of scientists whose job it is to decide how to slice our planet’s 4.5 billion-year history into manageable chunks. But in 2009, as climate change increasingly gained traction as a matter of public interest, the idea of actually making a formal designation started to appear in talks and papers. Today, if the scientific literature is any indication, the debate is fully ignited.
In fact, “it has been open season on the Anthropocene,” said Jan Zalasiewicz, a University of Leicester paleogeologist who is a leading voice in the debate. Within the last month a heap of new papers have come out with competing views on whether the Anthropocene is worthy of a formal designation, and if so, when exactly it began. The latest was published in Science today.
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Scientists Are Arguing About When, Exactly, Humans Started to Rule the Planet
