John Shepherd is a physicist who has worked on a wide range of environmental issues, including the transport and deposition of atmospheric sulphur dioxide, the dispersion of tracers in the deep ocean, the assessment and control of radioactive waste disposal in the sea, the assessment and management of marine fish stocks, and the ocean’s role in climate change. He was the first Director of the Southampton Oceanography Centre, and Deputy Director of the Tyndall Centre for Climate Change Research, and was elected a Fellow of the Royal Society in 1999 and awarded a CBE in 2010. He has been a member of the DEFRA Science Advisory Council and chaired the DECC Science Advisory Group from 2009 to 2013. He has been involved in several of the Royal Society’s science policy studies and chaired the study on Geoengineering the Climate in 2009. More recently he has helped prepare several public documents on climate science including the RS Summary of the Science and the recent joint RS/NAS briefing document.