Research focuses on how human and natural influences on climate contribute to observed climate change and extreme weather events. Has served on successive IPCC Assessments. Recent work has addressed the causes of the Autumn 2000 floods in the UK and the 2010 heat-wave in western Russia, together with quantifying the cumulative impact of carbon dioxide emissions and the relative importance of short- and long-lived climate forcing agents for future climate. Runs the climateprediction.net experiment, which has been the subject of two BBC television documentaries, winning the 2007 Prix Europa Internet Project of the Year. Recipient: Appleton Medal, Institute of Physics (2010).