Watch the trailer for Leonardo DiCaprio's new climate change documentary Before The Flood

Leo gives David Attenborough a serious run for his money in the gripping new trailer for his climate change documentary.

If you've wondered that Leonardo DiCaprio has been noticeably absent from the movie scene of late, a new trailer for his climate change documentary should shed some light on what he's been up to, and gives us yet another reason to love him.

Before The Flood is Leo's ambitious new documentary, in which he sees first-hand the effects of global warming and travels the world speaking to scientists, politicians and environmentalists about what he says is the 'most important issue of our time.'

Oscar-winner Fisher Stephens directs the project, while DiCaprio's has produced it under his Appian Way film company and narrates it, too.

In one scene after we a desperate polar bear and a glacier dramatically collapsing, he declares 'I just want to know how far we’ve gone, and if there’s anything we can do anything to stop it.'

DiCaprio isn't afraid to instigate his home country for its culpability in the devastating effects he sees, stating that 'The U.S. has been the biggest emitter of greenhouse gases in history,' and that 'half the people in office still don’t believe in climate change.'

A combination of Leo's passion for the issue, his oh-so soothing voice, the awe-inspiring footage and interviews with high-profile figures like Pope Francis and President Obama, all add up to a highly gripping viewing.

The documentary is already Oscar-tipped, and we can all watch it from our sofas when it airs on the National Geographic channel in 171 countries on 30 October, after limited US screenings next week.