Anthony Capon1, Ollie Jay2, Kristie Ebi3, Selina Lo4. 1. Sydney School of Public Health, Faculty of Medicine and Health, University of Sydney, Sydney, NSW 2006, Australia. Electronic address: tony.capon@sydney.edu.au. 2. Thermal Ergonomics Laboratory, Faculty of Health Sciences, University of Sydney, Sydney, NSW, Australia. 3. Center for Health and the Global Environment, School of Public Health, University of Washington, Seattle, WA, USA. 4. The Lancet, London, UK.