As part of our series about oceans, we're featuring a special bonus episode from our friends at Gimlet's How to Save a Planet. Hosts Alex Blumberg and Ayana Elizabeth Johnson explore how seaweed and giant kelp can help us address climate change and how fisherman Bren Smith has become kelp's unlikely evangelist. Listen to more episodes of How to Save a Planet on Spotify, including part II of Bren Smith's story. Follow How to Save a Planet and host Alex Blumberg and Ayana Elizabeth Johnson on Twitter. (Warning: This episode contains some explicit language).