Transcript for Jane Fonda on changing her lifestyle to combat climate change
Reporter: Jane fonda still pushing boundaries. We are all here today because we know what lies ahead. Reporter: Lately a fixture on capitol hill. Sounding the alarm on climate change. Shut it down! Reporter: Bringing together average folks along with activists like Gloria steinem and Hollywood a-listers like Joaquin Phoenix and Rosanna Arquette. Two, four, six, eight, save the world it's not too late! Reporter: Fonda's voice now part of a growing chorus of celebrities concerned about our planet, including Leonardo Dicaprio, who spoke at this year's global citizens festival in New York. Our future is being gambled away. Reporter: Russell Crowe, whose comments delivered at the golden globes by Jennifer aniston talked about the wildfires in Australia. Make no mistake, the tragedy unfolding in Australia is climate based. Are fonda's mission is she's leading weekly protests in Washington, D.C. With her group fire drill Fridays hoping to inspire others to take action in any way they can. It's a tough time right now. A lot of people are feeling hopeless about our world. Are you hopeful at this moment? Yes, yeah. I mean, activism makes you hopeful. I was very depressed until I decided to come here and do the minute I came here and began to engage in activism with my whole body, I overcame the depression. That's what activism can do. When you're doing something that you think can possibly make a difference, it lifts despair. Reporter: You might expect this privileged Hollywood icon to be slowing down. Enjoying the fruits of an illustrious career. Instead, on the eve of her 82nd birthday, fonda's being led out of the hart senate building in handcuffs, arrested for civil disobedience. How many times have you been arrested since September, since you began this? I think five? I'm not sure, I've lost count. Reporter: She began her recent crusade back in October. Inspired by teen activist Greta Thunberg, who's been boycotting school every Friday since last year to protest climate change. All these young people striking on Friday saying, come on, adults, where are you? We didn't cause this. So I thought, well what can I do? I want to be able to put my body on the line and kind of role model what the next step should look like. Specifically what would you feel successful about, if you saw something changed? Here's the thing. In cities all over the country and states, they're all at the table figuring out what has to be done to reduce the carbon footprint. It's happening, it's just now it has to happen globally. Reporter: Fonda, born into Hollywood royalty, made her mark in the iconic film "Hagarellao." Later she built a workout empire. Her personal fitness videos selling millions worldwide. But her activism has garnered just as much attention along the way. She's grown accustomed to being arrested, becoming a regular at protests for years. Both revered and reviled for her efforts. Fonda found her voice back in the '60s after taking a stand against the Vietnam war. A trip to Hanoi landed the actress in hat water with veterans who believed she was anti-american. But that was just the beginning for Jane fonda. You've been putting your body on the line for a very long time for a lot of causes. The Vietnam war, civil rights, teen pregnancy, reproductive rights, indigenous people's rights, violence against women, the expansion of the west bank settlements, the Iraq war, north Dakota pipeline, climate change. So much. How is it different for you now? What's different is what it is I'm protesting about. There's never been a ticking time bomb hanging over our you know, this isn't one war or one issue in one place. This is the future of the entire planet. It's a global thing, and it's very, very, very urgent. This idea of protesting, getting arrested, isn't new for you. But you're not in your 30s anymore, when you started this kind of activism. How tough is it now getting arrested and spending a night in jail? Most of the time we're engaging in civil disobedience, which is a time-honored, noble thing to do. You get held awhile, pay $50, you get let go. But it does attract media attention. That's why you're here. Which is why you're here. Yeah. Which is what we need to do. People tend to say, my god, she's almost 82, if she can do it, I can do it. It's the next step up. Reporter: For fonda, it's important that she's not just talking the talk. A lot of people notice you and they certainly notice you in your red coat. That's gotten to be your signature. I had to get something read. I went to Neiman's and it was on sale. So I bought it. Never buying anything new again. It's easy for me to say, I'm 82, and I don't have that much time to worry about it. It's becoming a thing, consumerism. And so I thought, well, that's another way that I can try to be a role model. No more. Well, I might buy underwear. And socks. I seem to put holes in socks. You're not going to do any major fashion purchases, you're not shopping really? No. I try to fly less. I've gotten rid of single-use plans tibs, I've gotten rid of the car. Reporter: She's been joined by people like Taylor Schilling of "Orange is the new black," ice cream bigwigs Jerry Cohen and Ben green field, lily Tomlin, her "Grace and franky" costar. Two, four, six, eight, save the world it's not too late! Reporter: She marched with photographer Annie leibovitz. And of course some Hollywood star power. I think the best way to honor Jane is maybe on her birthday, to be here. It's our right as American citizens to be able to protest things that are unjust. And killing the planet, we need to wake up and do something about it. There's so many fantastic people that are coming and going to engage in civil disobedience with me. It moves me so much. I think that together we're going to be braver and stronger. To then go out each in our own way and step it up. A very different kind of birthday celebration. Yeah. Reporter: When we sat down to talk, fonda's long-time friend and fellow activist Sally field joined in. I'm here today because I know Jane is right. It's now we have to get loud. I live in California. If you think climate change isn't happening, come live in California for a few months. The whole state is being burnt to the ground. It's terrifying. In the United States, there is not a region that is left untouched. It has to be done now. This is about me maybe not so much, it's about my children and my grandchildren. You say you've been passionate and you've been an activist in some ways, but this idea of protesting and getting arrested, that's new for you. Oh, yeah. It's 73, it's time to get arrested with Jane. Putting your body on the line. Jane is sitting there nodding so proudly like a teacher. But it's right, she's so right to get excited. Putting it on the line. I love this woman, I admire her so greatly. And you know, it's time. Reporter: Later that afternoon, true to her word, she was led down the steps of the capitol in zip tie handcuffs. It's a very transformative experience because it's art in life these days to be able to align your body with your deepest values. When the two parts of your selves, your physical self and your spiritual self, can align. That's very empowering and transformative. That's what happens when you engage in civil disobedience and risk getting arrested. How much did your faith impact what you're doing? It gives me a lot of strength. And I believe in the power of You light up when you talk about this. It's true. You can ask the people that have joined me. You can ask the young people that inspired me, that have been out there every Friday. I wish it didn't take a celebrity to get people to pay attention. Because what they're doing is awesome. Reporter: I'm Deborah Roberts for "Nightline" in Washington,
This transcript has been automatically generated and may not be 100% accurate.