Gayathri Vaidyanathan

Environment/science reporter

Searching for the Human Age


Discover; Oct. 2, 2014

Gary Stinchcomb walks into a Paleo-Indian dig site shaded by a canopy of trees in Pennsylvania’s Lehigh Gorge State Park. He weaves past holes dug by looters hunting for pieces of human prehistory: knives, scrapers, projectile points.

At a tarp sheltering a 6-foot-deep pit, he stops and climbs into the hole. On the bottom are large boulders left behind by glaciers some 12,000 years ago. It was around that time that Paleo-Indians arrived in this part of the Lehigh Valley.
Stinchcomb, a geologist at Murray State University in Kentucky, is there looking for traces of a more recent past. He is searching for evidence that Earth has entered the Anthropocene, a new epoch defined by the idea that humans have surpassed nature as the primary shapers of the planet.

Scientists are divided over whether to formally recognize the Anthropocene, or the Human Age, as a bona fide geologic time period. To establish a new epoch, geologists usually have to find clear evidence in the rock record of a massive, planet-altering shift. Human-caused change is undeniable, but have we truly become master engineers of the planet?

Stinchcomb believes he’s found a way to resolve some of the debate. The clues for humanity’s entrance into the Anthropocene, he says, lie in the traces we’ve left behind in layers of sediment and soil. What’s needed is a concerted effort to plot these imprints and use them to show when the epoch of the past 11,500 years, the Holocene, could have yielded to the Anthropocene.