Heat mortality in Berlin – Spatial variability at the neighborhood scale

Abstract

Heat stress increasingly affects urban populations in higher geographical latitudes. Related adverse health effects are expected to increase due to urbanization, population aging, and global warming. While many studies have examined the relationship between heat and mortality, only a few have examined the intra-urban spatial variability between them. This missing research is particularly evident for northern mid-latitude cities, where populations are not prepared for heat stress. The aim of this study is therefore to investigate heat-related excess mortality in its spatial variability at the neighborhood scale (397 planning areas) for Berlin, the capital of Germany. We analyzed age-standardized mortality rates by calculating the relative heat mortality risk ratio for months with and without severe heat waves. Local indicators of spatial association were used to locate spatial clusters. The results highlighted the intra-urban variability of heat-related excess mortality, and demonstrated clustering for the planning areas of Berlin. Temporal aggregation of mortality data enabled a neighborhood-scale analysis. Resulting heat-related excess mortality maps allow urban decision makers to identify hot spots for emergency and adaptation planning, and serve as a basis for further investigations of heat stress risk on an individual level.