Five eminent thinkers speak from around the world on different aspects of the complex theme of sustainable development. At the end of the series the lecturers will come together for a final round-table discussion hosted by the Prince of Wales. Presented by Kate Adie.

Leading scientist Thomas E. Lovejoy, chief biodiversity adviser to the World Bank and councillor at the Smithsonian Institution in Washington, tells an audience in Los Angeles: "We are in deep trouble biologically and already into a spasm of extinction of our own making unequalled since the one which took the dinosaurs."

(Repeated Saturday 10.15pm)
Lectures published on: [web address removed]