Dr Paul D. Williams is Professor of Atmospheric Science at the University of Reading, UK. He was educated at Oxford University, receiving a first-class degree in physics and a PhD in atmospheric physics. He specialises in atmospheric modelling, turbulence, and climate change. In particular, he is noted for his published studies showing that climate change could double or treble the amount of severe turbulence in the atmosphere, causing aircraft flights to become much bumpier in the coming decades. He has published two books and over 50 peer-reviewed scientific papers in leading journals, including Nature. He has held visiting fellowships at the Universities of Cambridge and California. He is a Fellow of the Institute of Physics, the Royal Meteorological Society, and the Royal Astronomical Society. His frequent TV and radio appearances have included the BBC, Sky News, CNN, The Discovery Channel, and The Weather Channel. He tweets regularly about atmospheric science as @DrPaulDWilliams.