Abstract: The Sahara is our largest hot desert. It extends 5000 km from west to east and 3000 km from north to south. Driving across the Sahara is like being on the moon. Not a blade of grass. Nothing but sand, wind, dust; dust, wind, sand. Present aridity contrasts with abundant evidence that the Sahara was once a green and pleasant land. Rock paintings and rock engravings of elephants, giraffes and rhinos are common on sheltered rock outcrops throughout the desert. The rock paintings also depict scenes of cattle herding. Even more persuasive is the evidence provided by the fossil remains of hippos, crocodiles, turtles and Nile perch embedded in now dry lake sediments. When and why was the Sahara once able to support such an abundance of life? When and why did it become dry? Did humans cause the Sahara to become a desert? This talk will seek to answer these questions
Bio: Martin Williams has always been fascinated by desert landscapes. He has travelled widely in many parts of the Sahara and has worked with international teams of archaeologists and geologists in some of the remoter parts of that vast desert. His more recent books include Climate Change in Deserts (CUP, 2014), Nile Waters and Saharan Sands (Springer, 2016) and The Nile Basin (CUP, 2019). His latest book When the Sahara was Green: The story of our greatest desert is written for non-specialist readers. It will be published next year by Princeton University Press. He is Professor Emeritus and Adjunct Professor in Earth Sciences at the University of Adelaide, Australia.