Extreme Heat, Vulnerable Populations and Adverse Health Outcomes: Informing Targeted Climate Change Adaptation Planning.

Abstract

Heat-related deaths in the United States, although entirely preventable, account for largest proportion of mortality attributed to weather. The expectation that, with climate change, extreme heat events will occur more frequently, last longer and have more intensity, has significant implications for human health. To inform the development of interventions and program that protect the public from the deleterious effects of a changing climate, accurate identification of the populations most vulnerable to extreme temperature is urgently needed.

Building from the extensive epidemiological research on heat-related mortality, this research addresses gaps in methodologies commonly used to characterize the impacts of extreme heat on population health. The first section presents a novel method for estimating, or ‘downscaling’, epidemiologic effect estimates of the association between extreme heat and mortality to the census tract level for 20 large U.S. cities, 1990-2006. Results were mapped to display city-specific spatial patterns of the risk of heat-related death among subpopulations defined by age, race and gender. Spatial patterns varied across city, suggesting that this method could be used to evaluate the possible location of vulnerable populations. The second aim examined whether the creation of 21, fine-spatial-scale heat vulnerability indices would depict consistent, explicit spatial patterns of vulnerability across 913 Census block groups in Detroit, Michigan. Spatial patterns of vulnerability were dependent on the combination of input variables including in the index computation. Lastly, geocoded mortality data (2000-2009) was used to evaluate whether the fine-scale heat vulnerability indices accurately identified census block groups where heat-related risk was the highest. The results indicated an effect opposite to that expected of the predictive capability of the indices in identifying high risk areas in Detroit. Future research on heat-health associations in the context of climate change should focus on developing and evaluating precise methodologies for identifying fine-scale vulnerability and informing targeted interventions.