Scientists working off the West African coast have discovered evidence of dramatic climate change - more than three million years ago. They believe there was a ten-degree drop in temperature, just at the moment when our earliest ancestors were emerging in subtropical Africa. Quentin Cooper talks to Dr Jeremy Marlow who led the international team, who believes that the fall in temperature had a significant impact on human evolution. How different might we have been if the temperature had not dropped? Producer John Watkins. E-MAIL: scirad@bbc.ac.uk