Kenneth Lacovara: What's The Anthropocene? Have we entered a new age defined by humans? Paleontologist Kenneth Lacovara says there's "no doubt" that humans' impact on Earth will show up in the geological record.

What's The Anthropocene?

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GUY RAZ, HOST:

It's the TED Radio Hour from NPR. I'm Guy Raz.

Did you know that the birthplace of dinosaur paleontology is actually in New Jersey?

KENNETH LACOVARA: It is. The world's first really substantial dinosaur skeleton was found in Haddonfield, N.J., in 1858. And the world's first tyrannosaur was found about a mile from my quarry 150 years ago this week.

RAZ: This is Ken Lacovara. He's a paleontologist and dean...

LACOVARA: ...Of the School of Earth and Environment at Rowan University.

RAZ: Which runs a dinosaur quarry in New Jersey.

LACOVARA: Wonderful place.

RAZ: Yeah. The New Jersey Turnpike doesn't exactly scream birthplace of paleontology.

LACOVARA: It does not.

RAZ: Yeah, because you just go by, like, factories and...

LACOVARA: Yeah.

RAZ: ...You don't think about dinosaurs when you're there.

LACOVARA: I do.

RAZ: You do.

(LAUGHTER)

RAZ: You do when you're driving down the New Jersey Turnpike?

LACOVARA: Well, I do because I know what geological formations I'm driving over.

RAZ: OK. So just out of curiosity, driving down the New Jersey Turnpike, if you were, like, a dinosaur and you went back in time, what would that look like?

LACOVARA: Well, if you were back in the Cretaceous Period - the last of the time of the dinosaurs - and you were driving from New York to Philadelphia on the New Jersey Turnpike, you would be driving across water...

(SOUNDBITE OF WATER SPLASH)

LACOVARA: ...For the most part. So the coastline would be a little bit to the west of there. And so the dinosaurs that we find in New Jersey are what we call the bloat and float dinosaur. So these are dinosaurs that died on the beach, ended up in the water, probably initially sank when they get a lung full of water and then the body starts to decay. And as those decay gases build up in the body, the carcass floats. They become, like, this big giant bobbing meat buoy at sea. And as the body decays, then pieces of the skeleton start to drop out of the carcass and settle to the sea floor. And that's what we find in the Cretaceous deposits of New Jersey.

RAZ: And those Cretaceous deposits mark a geological era. And eras are how geologists measure time. And they're usually created by these big, world-changing events.

LACOVARA: And so when the dinosaurs go extinct and 75 percent of life goes extinct after a meteor hits the planet, that's an era boundary. That's when we change from the Mesozoic to the Cenozoic.

RAZ: So think of an era kind of like an hour on the clock, right? It's a lot of time, tens of millions of years. And like an hour, it's made up of smaller increments. But instead of minutes and seconds, they're known as periods and epochs.

LACOVARA: In our case, we are in the Cenozoic Era, which started at the end of the time of the dinosaurs. We are in the Quaternary Period, which is within the Cenozoic Era. And within the Quaternary, we are in the Holocene Epoch.

RAZ: The Holocene Epoch, basically defined by the development of our human civilization. But in geological time, the Holocene is tiny, only the last 11,700 years, or basically since the end of the last ice age.

LACOVARA: It's roughly correlated with that. The technical definition of the Holocene has to do with the extinction of a snail species in Sicily.

RAZ: Oh, really?

LACOVARA: Yeah.

RAZ: Wow. Just one snail species?

LACOVARA: They have to find a - yeah. They have to find a marker...

RAZ: Wow.

LACOVARA: ...So other geologists can say, well, there it is. There's the snail, there's not the snail. That's when we set the boundary.

RAZ: Humans, here's your age. A snail died in Italy.

LACOVARA: Right.

RAZ: Wow.

LACOVARA: Yeah.

RAZ: But here's the thing, a lot has changed since that snail died in Italy. We humans have made our presence felt on the planet more than any other species in Earth's history. And what that means for our future isn't yet clear.

LACOVARA: And so it was Winston Churchill who said the further back you look, the further ahead you can see. And so if we want to know how the Earth's biosphere is going to respond to the things that humans are doing to the planet right now, the only evidence that we have is how biotic systems have responded in the past.

RAZ: And based on the past several million years, we know the Earth goes through natural cycles of cooling. In fact, 20,000 years ago, most of North America was covered in a giant ice sheet.

LACOVARA: Might have been a mile or more high at the North Pole, that extended all the way down to East Brunswick, N.J. or the Lehigh Valley in Pennsylvania or deep down into Illinois in the Midwest. Just south of that where southern New Jersey is, that was tundra.

RAZ: And based on that past, we know that the Earth - it should be getting cooler right about now.

LACOVARA: But it's not. It's getting warmer. And the divergence between where we know we ought to be and where we're going, we can attribute that to the human influence that we're having on the climate.

RAZ: And for that reason, some scientists have proposed thinking about our place in geological history differently, that the world today is a lot different than it was when that snail died in Italy. And that we need a new term for a new epoch - the Anthropocene.

LACOVARA: The Anthropocene essentially would be the time of human influence on the planet. That's controversial though, because geology is a retrospective discipline. The rocks of the Anthropocene haven't been deposited yet, really. But at the same time, I think it's a really useful tool in the same way that we would discuss the Iron Age or the Bronze Age.

Certainly, we have entered into a new age on our planet. We're changing things, in many cases in irreparable ways, and that will certainly be recorded in the geological record. There's no doubt if you could go 5, 10, 15 million years into the future and dig down to 2016, you would be able to find the geological evidence that humans occupied the planet.

RAZ: So today on the show, the Anthropocene. Ideas about a new human age, an age that's changing our planet in unprecedented ways, and what that might mean for our future.

Ken Lacovara returns later with the story of one dinosaur that reveals a lot about where we're headed.

But first, how should we relate to the idea of the Anthropocene right now?

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