Katherine Dewar's novel Ruby and the Blue Sky

In her political thriller Ruby and the Blue Sky, Katherine Dewar blends the environment with rock n roll. In the near future, an international pop star goes viral when she calls for young people to rally and save the planet. But when eco-groupies start pursuing her, she has to decide if she's willing to lead the movement. Katherine Dewar tells Lynn Freeman how she's worked on campaigns for environmental change for more than 20 years.