On top of the plethora of documentaries that have already been made on the subject of global warming, we can now add actor-turned-director Fisher Stevens‘ Before the Flood. As is so often the case, the film is built around an investigation into the effects that global warming has had on our planet and the (largely man-made) causes of this tremendously destructive happening. The crucial difference? Where the other films were stacked with nothing but experts, with a possible cameo from a celebrity who passionately believes in fighting against global warming, this one is centered on Leonardo DiCaprio, who gamely plays the part of guinea pig for a bunch of experts to explain what exactly is going on with Earth.

With the release of the first trailer for the documentary, which you can take a look at below, one gets a better sense of the film outside of the realm of a political passion project for arguably the biggest actor in the entire world. This doesn’t feel like Brad Pitts‘ cameo in 12 Years a Slave, though. What can be seen from the trailer is fascination and concern, which are two key components to any decent non-fiction movie these days.

Before the Flood will debut in theaters on October 21st and will then play on National Geographic starting on October 30th.