9 Centre on Climate Change and Planetary Health, London School of Hygiene and Tropical Medicine, Keppel Street, London, WC1E 7HT, UK. p.wilkinson@lshtm.ac.uk.
10 Department of Public Health, Environments and Society, London School of Hygiene and Tropical Medicine, 15-17 Tavistock Place, London, WC1H 9SH, UK. p.wilkinson@lshtm.ac.uk.