Star Leonardo DiCaprio has a message for the world: that climate change is a very real threat to millions of people around the world, and governments and the public should act now to avoid the worst impacts.

DiCaprio, a United Nations Messenger of Peace, told that organization: "A massive change is required right now. One that leads to a new collective consciousness. A new collective evolution of the human race, inspired and enabled by a sense of urgency from all of you."

DiCaprio was speaking after world leaders came together to agree to limit global warming to 2°C, after meeting in Paris last winter. The actor's words appear in the upcoming documentary film Before the Flood, which will air on