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December 16, 2016
Q. Jurassic, Cretaceous, Pleistocene… and now Holocene, which began some 12,000 years ago — such epochs comprise a complex geologic time scale, characterizing how Earth evolved. But some scientists are beginning to wonder if the impact of humans on our planet calls for the naming of a new epoch — the Anthropocene (“anthropo” meaning “human”). Why seriously consider it?
A. Writing in Scientific American magazine, paleobiologist Jan Zalasiewicz describes a number of human geological signatures which will persist for eons. Since World War II we have extracted and purified enough aluminum to “coat the entire U.S. in kitchen foil,” with pure aluminum “becoming part of modern sediment layers.” Today the annual production of plastics is “roughly equivalent to the total human body mass,” and we've manufactured “about a kilogram (2.2 pounds) of concrete for every square meter (about a square yard) of the earth's surface.” Human-created smoke particles falling to the ground worldwide form “a geologically lasting smoke signal.” And astonishingly, “humans shift more sediment than natural forces such as rivers and wind do.”
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