In his new documentary, Before the Flood, Leonardo DiCaprio takes viewers on an eye-opening tour of how climate change is affecting the planet's oceans right now, from rising seas threatening Miami to the perilously melting Arctic.

One of the experts DiCaprio meets in the film is Enric Sala, a marine biologist and National Geographic explorer-in-residence. Sala is working to study, document, and protect some of the most biologically important areas of the ocean through the Pristine Seas project.

We spoke with Sala about his work and role in the new film.

Read the full story in National Geographic.