Impacts of climate change and urban heat island on mortality risk: summer average vs. extreme heat events

Climate change is expected to increase heat-related mortality risks. However, mortality risks associated with cold weather, which can also occur during summertime, are expected to decrease. The overall impact of temperature changes on summer average risk may therefore evolve differently than the risk associated with heat extremes. A similar, though less pronounced, picture can also be painted for the impact of urban heat island on mortality risk. In two separate studies, we highlight the differing impacts of warming on summer mean versus extreme heat-related mortality risk. Factors such as the local climate and vulnerability to heat play a role in mediating the net summer average impact, while a clear enhancement of risk during extreme heat events is expected in association with both climate change and urban heat island effects. These findings provide a more comprehensive picture of the potential impact of climate change and urbanisation on summer temperature-related mortality risks, which may be relevant for adaptation and mitigation strategies.