Comparing Approximated Heat Stress Measures Across the United States

Abstract

Climate change is escalating the threat of heat stress to global public health, with the majority of humans today facing increasingly severe and prolonged heat waves. Accurate weather data reflecting the complexity of measuring heat stress is crucial for reducing the impact of extreme heat on health worldwide. Previous studies have employed Heat Index (HI) and Wet Bulb Globe Temperature (WBGT) metrics to understand extreme heat exposure, forming the basis for heat stress guidelines. However, systematic comparisons of meteorological and climate data sets used for these metrics and the related parameters, like air temperature, humidity, wind speed, and solar radiation crucial for human thermoregulation, are lacking. We compared three heat measures (HImax, WBGTBernard, and WBGTLiljegren) approximated from gridded weather data sets (ERA5‐Land, PRISM, Daymet) with ground‐based data, revealing strong agreement from HI and WBGTBernard (R2 0.76–0.95, RMSE 1.69–6.64°C). Discrepancies varied by Köppen‐Geiger climates (e.g., Adjusted R2 HImax 0.88–0.95, WBGTBernard 0.79–0.97, and WBGTLiljegren 0.80–0.96), and metrological input variables (Adjusted R2 Tmax 0.86–0.94, Tmin 0.91–0.94, Wind 0.33, Solarmax 0.38, Solaravg 0.38, relative humidity 0.51–0.74). Gridded data sets can offer reliable heat exposure assessment, but further research and local networks are vital to reduce measurement errors to fully enhance our understanding of how heat stress measures link to health outcomes.

Heat‐related fatalities in North Carolina 1999–2017

“…and migrant workers are less likely to be documented for inclusions in the occupational fatalities database. Research on climate change-related mortality in other US jurisdictions and countries calls for improved surveillance and investigation of potentially heat-related deaths to mitigate this type of underestimation,23,24 which is particularly prevalent in minoritized populations 25. AUTHOR CONTRIBUTIONSElizabeth S. McClure designed the study, drafted the initial manuscript, analyzed the data, created the tables and figures, assisted with the literature review synthesis, and approved the final manuscript as submitted.…”