Anthropologist Noah Theriault contributes to the blog Inhabiting the Anthropocene, which examines how humans have influenced climate and the environment. He'll discuss this proposed geological epoch with Suzette Grillot.

But first, we check in with Rebecca Cruise, who's in Germany. The country recently saw four violent attacks in less than a week. 

A power plant
Wladimir Labeikovsky / Flickr (CC BY-SA 2.0)

No matter where you land on the climate change discussion, humans have become a geophysical force that impacts everything from local ecosystems to the atmosphere itself.

“Humans are having, for a single species, pretty much unprecedented effect on their entire biosphere, such that it could possibly be recorded permanently in the geological record,” University of Oklahoma anthropologist Noah Theriault argues. “If an extraterrestrial species came down and studied our planet sometime in the distant future, they would be able to tell there was some big change right around what we would consider to be the geological present.”

But what do you call that?

Erle Ellis

Over the last three decades, certain environmental scientists have started characterizing a new geological epoch, the Anthropocene, to mark the moment when humans started profoundly affecting ecological landscapes.

University of Maryland, Baltimore County ecologist Erle Ellis studies how agriculture, hunting, settlements, and other human activity have changed landscapes. He estimates three-quarters of earth’s land could be characterized as anthropogenic. But even as humans influence their environment, the mass influx of residents into urban centers can reverse that process.