Campaign and protest have been the traditional tools of environmental action in the UK. American lawyer, James Thornton, set up Client Earth to defend the planet in a different way- by using the courts. Using local laws to challenge governments and businesses they've had success across Europe and beyond, preventing the construction of coal-fired power stations and challenging the curse of air pollution. As well as enforcing environmental laws they're helping get new laws written. Tom Heap meets James and discusses the carbon implications of his ideas with climate scientist, Dr Tamsin Edwards. Producer: Anne-Marie Bullock Photo of James Thornton by Dan Wilton. Series made in partnership with the Royal Geographical Society