John Mitchell (1948-), meteorologist, worked for the Meteorological Office throughout his career, after a PhD in nuclear physics. In the Dynamical Climatology Branch he helped to develop computer models of the atmosphere called GCMs (Global Climate Models/Global Circulation Models), especially by ‘adding’ interaction with a more realistic ocean. In the 1980s he successfully used Met Office GCMs to predict theeffect of increasing concentrations of carbon dioxide in the atmosphere. Following its establishment in 1990, he led the development of GCMs in the Hadley Centre for Climate Prediction and Research and has contributed to the Intergovernmental Panel on Climate Change’s (IPCC) Climate Change Assessments. These two areas of work are closely linked: for example the very successful HADCM3 GCM was used extensively in the third IPCC Assessment (2001). He served as Chief Scientist at the Met Office from 2002 to 2008 and Director of Climate Science from 2008 to 2010; he is currently a Principal Research Fellow.