Actor and environmental activist Leonardo DiCaprio is furiously trying to get the world to take get serious about climate change.

He uses every platform he can to wake people up to the reality of the growing environmental crisis. 

DiCaprio delivered an impassioned speech at the the UN, used his first Oscar victory speech to advocate for the environment, and even spoke on the Global Citizen Festival Stage. 

Oh, and his foundation gives out millions of dollars in grants for all sorts of sustainability and conservation projects. 

Read More: The Other Reasons Leonardo DiCaprio Deserves an Award

Now DiCaprio's racing around the world to spread the news even further. In a stunning new documentary, "Before The Flood," that will be released Oct. 21, he watches massive pillars of ice collapse, explores fragile coreal reefs, and hovers above moutain ranges shredded by explosives. 

All throughout, his question is simple and urgent: "Can we change our course in time?"