David de Rothschild spoke to me by phone from San Francisco. We talked about the narrative power of adventures, the economics of the plastic industry, and how an Evian bottle thrown away in Illinois can end up in the middle of the Atlantic.

You're an ecologist, activist, journalist, TV host, traveler. How would you describe your profession?

I want to give nature a voice through storytelling—and this requires a kind of focused environmental ADD. You know, there's no such thing as a box in nature. Boxes are human inventions. And to tackle these issues you have to think outside the box, otherwise you're limiting your scope and your work. You have to be a champion of change across all mediums, whether that's through TV, design, exploration, traveling, teaching, talking, touring, whatever it is.

So why is adventuring, in your view, an important way to shed light on our ecological challenges?

Adventure is a very charming medium, in the sense that it's far more attractive to learn about something in an adventurous way than the old-school, wordy way. The old-school method goes like, "Um, the oceans are screwed, they're filling up with plastic, you're part of the problem—and, oh, you should be interested in this." Right?

Our method is to say, "The oceans have a problem, but we're going to build a boat out of plastic bottles, sail across the world on it, prove anything's possible. Do you want to get involved?" Which one would you rather go for? Adventure allows better integration of the message, and more accessibility to the message.

Not only that, adventures generate stories, and stories inspire more people to dream and ultimately ask questions. Someone who's seen the Plastiki might also then turn around and start asking: "Can I build a boat? Can I undertake my own adventure? If he can build this boat out of plastic bottles and sail across the south Pacific, can't I become more sustainable in my everyday life?" As soon as someone starts asking questions, they're on their own adventure.

What went into the boat's creation? What's so noteworthy about the design of your craft, the Plastiki?

We tried to make it—on every level—as sustainable as possible. To do that meant that we had to avoid the path of least resistance. And in order to do that, we had to innovate.

One breakthrough was realizing that pressurizing bottles gives them more integrity and strength. By putting C02 powder in every bottle and letting it evaporate into a gas, we found a way to turn a weak structure into an incredibly strong structure. This emphasizes the design work that goes into plastic bottles—how incredible the engineering is, how resilient these things are, and yet how disposable we make them.

The second big breakthrough was the structural material that we developed [the recycled PET compound, Seretex], which allowed us to generate the Plastiki's skeletal structure. That was an enormous breakthrough because not only did that allow us the longitudinal rigidity, the strength down the length of the boat. But it's also allowed to take plastic—and show that we can take discarded plastic bottles and effectively create a material that doesn't need to be like-for-like—take one plastic to make another plastic bottle. But you can take a plastic bottle and build a bridge. You can build a boat. You can build a house. You can build rooftops. You can build skateboards. You can build whatever you can build now with this material. What that does is change the narrative that plastic is valueless and single-use—now [it] becomes, "Plastic is valuable and multi-use."