1 Steven Sherwood is a professor at the Australia Research Council Centre of Excellence for Climate Extremes at the University of South Wales, Sydney, Australia. s.sherwood@unsw.edu.au.
2 Brian Hoskins is chair of the Grantham Institute at Imperial College London, London, UK, and a professor in the Department of Meteorology at the University of Reading, Reading, UK. b.hoskins@imperial.ac.uk.