Fertiliser and poison gas: The legacy of chemist Fritz Haber

German chemist Fritz Haber's discovery of how to turn atmospheric nitrogen into ammonia is seen as one of the most significant of 20th century science - it enabled the industrial manufacture of fertilisers, which now provide food for up to half the planet's people. But he was also responsible for the development and deployment of poison gas on the battlefields of World War One and is remembered by some as the 'father of chemical warfare'. His was also a life touched by personal tragedy and a struggle against a Jewish heritage that at first threatened to hold back his career, and would later send him into exile. Bridget Kendall examines a life that epitomises science’s capacity to create and to destroy. Contributors: Dan Charles, US journalist and author of ‘Master Mind: The Rise And Fall Of Fritz Haber, The Nobel Laureate Who Launched The Age Of Chemical Warfare’; Shulamit Volkov, professor emerita of European and especially German History at the University of Tel Aviv, Israel; Dr Anthony Travis, senior researcher in the history of technology at the Sidney M. Edelstein Centre for the History and Philosophy of Science, Technology and Medicine, at The Hebrew University of Jerusalem, and author of ‘Nitrogen Capture: The Growth of an International Industry’. (Image: A portrait photograph of Fritz Haber, dated around 1920. Credit: ullstein bild via Getty Images)