Establishing intensifying chronic exposure to extreme heat as a slow onset event with implications for health, wellbeing, productivity, society and economy

The Warsaw International Mechanism for Loss and Damage has identified increasing temperatures as a key slow onset event. However, it is the resulting increases in short-term heat events — heatwaves — that have so far been the primary focus of risk assessment and policy, while gradual and sustained increases in temperature have received less attention. This is a global issue but particularly important in tropical and subtropical regions already chronically exposed to extreme heat. This paper reviews recent analyses of intensifying seasonal and year-round extreme heat exposures and how this affects daily life, including worker productivity, health and wellbeing, reduced GDP and economic viability. It frames this as a slow onset event and closes with a brief indication of tools available to assess and address these risks.