It’s an understatement to say that renowned paleontologist Kirk Johnson has done some traveling: he’s been to the Amazon 15 times, Antarctica seven. He’s led hundreds of fossil expeditions, from Australia to the Canadian Rockies. His day job: Sant Director of the Smithsonian’s National Museum of Natural History, the most visited natural history museum in the world. He has accomplished most people’s bucket lists many times over. But it was his travels as host of NOVA’s Polar Extremes that gets his top kudos, “my dream project.” In this new NOVA film, Johnson travels to the polar extremes of our planet — and back in time — to show viewers potential parallels to our present and future climate story. We caught up with Johnson over sandwiches before a recent full-house preview of the show at WGBH Studios in Boston.

What’s the best thing about your line of work?

Kirk: I have the number one key to the planet, because I'm a paleontologist. I love planet Earth. I love rain forests and deserts and mountains and coastlines. My true love is being outside in amazing places. That's bliss to me. And no matter where you go, there are plant fossils that can tell you something about our changing climate.

You travel with the same team, trip after trip. How do you all get along?

Kirk: The film crew I work with is the same one that worked on NOVA’s Making North America with me. For Polar Extremes, we traveled together for 78 days, but not all in one chunk. The longest trip was about three weeks. We’re all really close friends now. Together, we have taken an epic trip around the planet. Very few people get to see the places we’ve seen.

Is the Earth in a state of emergency?

Kirk: I personally don't like the term"‘climate emergency," but I think that this is the century when the human experiment on Earth is tested. And it may fail. It's an unknown outcome. I prefer to think about our collective desired outcome for this century and how to get there rather than worry about catastrophic scenarios.

What’s the most meaningful message of this film?

Kirk: Almost no one I have ever talked to has known that the polar regions were warm and forested for most of Earth history. That's the important message of this film. Once you realize that all of the ice did melt in the past, you realize that all of the ice could melt in the future. Because of human activity, the poles are melting more quickly now than they did millions of years ago.

We are in a race now to use human ingenuity to outwit humanity's impact on the climate. It’s easy to say that we can’t make it happen, but so many unexpected things have happened. We just might figure it out. With the right breakthroughs, governments and leaders — it's not impossible.

Stream NOVA's Polar Extremes for free here, and deepen your exploration of the poles with the Polar Lab, an immersive, multimedia game, or by watching the fun and quirky behind-the-scenes Antarctic Extremes, a new, 10-part digital series from NOVA and PBS Digital Studios about what it takes to conduct research in the planet’s most unforgiving climates.