This week on Environmental Politics I speak with Tom Bigg, director of Strategy and Learning at the International Institute for Environment and Development (IIED). IIED is one of the world's biggest names in promoting sustainable development, accruing an enormous amount of insight and influence in the nearly fifty years since its creation. My conversation with Tom covers the challenges and successes in promoting a sustainable development agenda in a world that displays the ever-increasing need to balance economic growth with environmental protection.