Working with Climate Projections to Estimate Heat-related Illness Disease Burden

Background Local public health agencies and practitioners are interested in estimating the future burden of climate-related health outcomes. Calculating future disease burden estimates can be especially daunting, given the complexities of climate modeling and the multiple pathways by which climate influences public health. In most cases, interdisciplinary coordination between public health and climatological experts is necessary for scientifically-derived estimates. We describe how a partnership of state and regional climate scientists and public health experts assembled by the Florida Building Resilience Against Climate Effects (BRACE) program collaborated to project future heat-related illness. This presentation expounds on the methodologies put forth in a submitted journal manuscript for combining climate and health data to project future disease burden and highlights the challenges to selecting climate data.

Methods We provide a brief background on climate modeling and projections, designed specifically with health scientists in mind. Selection criteria for climate projections are discussed in detail, including how climate model uncertainty is addressed. Downscaled climate projection data from ten global climate models are used to project the future health burden for the period 2040-2069 for six National Weather Service regions. Future disease burden is estimated using an attributable fraction approach. Attributable fractions are calculated for each value of maximum temperature above a reference range of 88°F (average maximum temperature for Florida during historical period 2005-2012).

Results Disease burden projection results are presented by six National Weather Service regions for the average number of heat-related illness cases per year for the period of interest (2040-2069), averaged across all ten global climate models. The average projected additional heat-related illness cases per year range from 36 to 421 across regions. Results are shown by region.

Conclusions Studying the associations between climate and health outcomes is a relatively new concept, and projecting future disease of climate-sensitive outcomes from within a state or local health department is novel. The methodology presented here highlights the challenges in selecting and organizing climate projection data, calculating future health burden and the importance of partnering with interdisciplinary subject matter experts.