Will there be a billion climate refugees?

Former Vice President Al Gore has said that climate change is predicted to lead to a billion climate refugees. But where do these predictions come from and are they realistic? We investigate the idea that floods, droughts, storms and sea level rise will cause a mass migration of people across borders. Reporter and Producer: Tom Colls Sound Mix: James Beard Editor: Richard Vadon (Photo: Floods in central Somalia Credit: Said Yusuf - WARSAME/EPA-EFE/REX/Shutterstock)