Too hot to handle: the global impact of extreme heat

Heatwaves are the deadliest weather hazard. Extreme heat also impacts cross-sections of society, from health to agriculture to infrastructure. The World Meteorological Organisation and the World Health Organisation recommend that countries should implement early warning systems to reduce the impacts of extreme heat. Despite this mandate no global heat hazard alert system currently exists. In addition, heatwave impacts are often under-reported by meteorological organisation databases and reports and in the English news media. This leads to them sometimes being known as silent or invisible killers. An interdisciplinary approach is taken in this thesis to investigate the impact of extreme heat and policy measures and to explore the development of a global heat hazard early warning system. This is presented through a systems approach framed using an adapted version of the WHO framework Operational framework for building climate resilient health systems. There are 4 components addressing different aspects of the system each with an objective and these are: 1. Mobilization and governance: assess policy prioritization and governance,2. Health Information Systems: evaluate the trends and modelling for extreme heat, 3. Essential Technologies: develop new technologies to reduce risk to heat and 4. Service Delivery: consider the communication of heat risks and impacts within wider culture. Overall, the research presented in this thesis provides research for a global heat hazard alert system focused on health impacts. An open-source python library for thermal comfort called thermofeel is developed and evaluated. In addition, the way in which extreme heat and heatwaves are communicated in English language research, policy and news media is explored, to start assessing what the best way to communicate heat stress risk might be on a global scale. All of this raises the profile of heatwave risk to ensure their impacts becomes more visible