Extreme heat has been responsible for more deaths in the United States than any other weather-related phenomenon over the past decade. The frequency and intensity of extreme heat events are projected to increase over the course of this century. In this work, we examine historical patterns of extreme heat exposure and mortality in the continental United States. We examine spatial variation in the mortality response to exposure, consider the contribution of key demographic and socio-economic factors in driving heat-related mortality, and test three different extreme heat thresholds using a national-level spatial autoregressive model and a geographically weighted regression approach. We find that the mortality response to exposure is higher in areas that do not routinely experience heat extremes, and that exposure itself is a stronger driver of heat-related mortality across the larger urban areas of the Midwest and Northeast. The importance of demographic/socio-economic factors varies substantially over space, and results are robust across alternative measures of heat extremes, suggesting that no single definition is necessarily superior. The baseline relationships established here are potentially useful for future predictions of exposure and heat-related mortality under alternative population and climate change scenarios, and may aid policy makers and planners in implementing effective adaptation and mitigation strategies.

过去十年，极端高温在美国造成的死亡人数比任何其他与天气相关的现象都要多。预计本世纪极端高温事件的频率和强度将会增加。在这项工作中，我们研究了美国大陆极端高温暴露和死亡率的历史模式。我们研究了死亡率对暴露反应的空间变化，考虑了关键人口和社会经济因素在推动与高温相关的死亡率方面的贡献，并使用国家级空间自回归模型和地理加权回归方法测试了三种不同的极端高温阈值。我们发现，在不经常经历极端高温的地区，暴露造成的死亡率更高，而且暴露本身是中西部和东北部较大城市地区与高温相关死亡的更强有力的驱动因素。人口/社会经济因素的重要性在不同空间中存在很大差异，并且在极端高温的其他衡量标准中结果都很稳健，这表明没有一个单一的定义一定是优越的。这里建立的基线关系可能有助于未来预测替代人口和气候变化情景下的暴露和与高温相关的死亡率，并可能有助于政策制定者和规划者实施有效的适应和缓解策略。