AUDIE CORNISH, HOST:
It's time for a big think conversation about cities as part of the NPR Cities Project.
UNIDENTIFIED MAN #1: We have to make sure that our cities are safe.
UNIDENTIFIED MAN #2: How are we going to maintain the city?
UNIDENTIFIED MAN #3: Location, location, location.
UNIDENTIFIED WOMAN: If other cities can do it, we can do it.
CORNISH: There's the city, and then there's the country - urban and rural. And we often think of these as separate things. But more than half the world's population lives in urban areas these days. And that percentage is rapidly increasing. Some scientists say our planet is now so influenced by our cities and all that human activity that we entered a new geologic era. They call it the Anthropocene, and with that change, we should be rethinking the relationship between civilization and nature. NPR blogger and astrophysicist Adam Frank has a big interest in this as someone who spends a lot of time thinking about planets. And he joins us now. Hey there, Adam.
ADAM FRANK, BYLINE: Hey, Audie.
CORNISH: So you're outside in Seattle, where you're going to be giving us your take on this. Where exactly are you, for starters?
FRANK: Well, I'm actually standing in this little park on the edge of Seattle's Capitol Hill district. And as a park, it's a lot like what you'd expect. There's some, you know, little plants. And there's some uncomfortable places to sit. And that pretty much is the traditional idea of cities and nature, right? You have some grass, some tress, some landscaping. But now as we enter the Anthropocene, people are beginning to think that that relationship has to go much deeper than parks. In their eyes, it's the city itself that really is its own kind of ecosystem.
CORNISH: What do you mean by that?
FRANK: Well, one of the reasons I'm out here is to work with a University of Washington professor Marina Alberti. She's a really creative researcher and she studies on how cities depend on nature and how they feed back on it. So Alberti likes to think in terms of what she calls hybrid ecosystems - that's a city. So she's interested in how cities depend on the flows of water and clean air and soil, but also how cities change those. So for one example, people have found that plants actually can adapt to the city by using the corridors of roads that we build for seed dispersal. Or there are birds, songbirds, whose songs actually change when they're inside the city compared to nature.
CORNISH: But, Adam, you know, cities haven't historically been exactly one with nature, right? I mean, people try to get out of the city to experience nature.
FRANK: That's true and that'll probably always happen but what we've got to understand is how big the impact of our cities has become now. So that means what we have to think about is their impact on the dark spaces. I really love that term. So, you know, we've all seen cities or maps of the Earth at night and we know that on those maps the cities show up as these bright, web works of light. And then you see the tendrils of roads that connect them. And all the dark spaces we think well that's the true home of nature. But the truth is really much more complex than that.
CORNISH: Well, how are the dark spaces connected to the cities?
FRANK: Well, I'm looking around here in the city, and what do I see? I see cars and trucks and traffic lights and air conditioning units and they're all consuming energy, right? You can hear that with the sound. But where does all this energy come from? Well, it comes from the oil-rich Alberta tar sands or it comes from West Virginia and mountaintop removal sites. These are massive industrial scale resource extraction projects and they're out there in those dark spaces. And it's our use of their energy here in the city that is changing the entire planet. So it's feeding back onto those dark spaces.
CORNISH: So, Adam, it sounds like you're basically advocating that we build nature into cities in a different way. Is that right?
FRANK: Well, building cities to act more like nature is one option. It's called biomimicry. And you can think of it as making cities more like trees, which get everything they need from where they stand. So along those lines, we're going to go from the park and we're going to walk into this building here, this very interesting building called the Bullitt Center. And you may have heard it before. It's called the greenest building in the world. OK. So we're inside the building now and I'm standing at this window and what I can see are a bunch of the very important design principles, the biomimicry design principles that are built into the building. So for example, I'm looking at the roof of the building and it actually extends beyond the walls. And that's because the designers thought the building should be like a forest. It should be like a canopy of a forest. So the solar panels up there are so extensive that they generate more power than the building actually needs. And here I'm looking out at this amazing rooftop garden. And it's a very different kind of garden because it's all horse tales and instead of being just something that's beautiful to look at, which it is, it's also a wetlands. And it functions to purify the water that the building uses before that water is actually returned to the ground. So there's a number of different ways and this building has become completely passive in the sense of only using what is available to it, and then returning all that back to the environment.
CORNISH: So, Adam, where do you think this is taking us as we enter this so-called age of the city?
FRANK: Well, I think with the dawning of the Anthropecene what's happening is we've become a truly planetary species, and that's what gets the astronomer inside me very excited. With all of our city building it's the entire planet that we're changing now. And, you know, once you get to that scale the decision between nature and not nature you've got to update that. Maybe it's time to really think about how nature and cities can evolve together.
CORNISH: All right, NPR blogger and astrophysics Adam Frank, in Seattle. Adam, thanks so much for talking with us.
FRANK: Oh, it was my pleasure.
CORNISH: And the Cities Project wants your photos and stories about nature showing up in your town on Twitter, Tumblr and Instagram. Use the hashtag #NPRcities. Transcript provided by NPR, Copyright NPR.