Swedish campaigner Greta Thunberg made a passionate speech at the UN this week, accusing world leaders of failing to act on climate change. She told them: "You are failing us. But the young people are starting to understand your betrayal. The eyes of all future generations are upon you."

It’s hard to remember that a year ago we had not heard the name Greta Thunberg, that she was just a lone teenager staging her solo climate strike outside the Swedish parliament on Fridays. Now she’s having the camera trained on her to gauge her reaction as Donald Trump walks by and her speeches are being broadcast around the world.

What Greta says is scary, but that’s the point. In this episode we speak to David Wallace Wells, author of The Uninhabitable Earth. David, like Greta, has spent a lot of time going through climate studies and talking to the scientists who’ve measured where we’re heading. In this episode he tells us how much our future remains in our hands.

Presenter: Matthew Price

Producer: Duncan Barber

Mixed by Nicolas Raufast

Editor: John Shields