Number of Americans Who Die Prematurely Due to Heat Exposure Could Skyrocket by 2100, Climate Change Study Warns

By Kam Kompani,

April 14, 2020

The number of Americans who die prematurely due to heat-related complications could rise by a factor of nine by the end of the century, according to a recent study, bringing the total to more than 100,000 deaths annually. Over the past decade, 12,000 Americans have died each year due to heat exposure.

The authors found that the number of annual deaths could be limited to 48,000 under a more moderate scenario; and even statistically unchanged under an “aggressive mitigation scenario”.

Among other adaptation measures, the study’s aggressive mitigation scenario assumed that people could adapt to warmer temperatures. For example, people could change their personal habits to minimize their exposure to heat, or cooling centers could be built for those without air conditioning, the authors suggested.



In Arizona, the annual number of deaths attributed to heat exposure more than tripled from 76 deaths in 2014 to 235 in 2017. Heat-related deaths in Nevada rose almost fivefold (from 29 to 139) during the same period.

If the adaptation measures are implemented perfectly, approximately 17,000 Americans (5,000 more people than the current average) could die prematurely each year due to heat-related complications by 2100. The authors, however, warned that a “fully synchronous adaptation to all aspects of changing temperatures seems implausible. A more likely scenario would be around 50,000 premature deaths per year.

Exposure to heat can compromise the body’s ability to regulate its temperature, “potentially resulting in heat exhaustion, hyperthermia, worsening of chronic conditions, and heatstroke, leading to temperature-related deaths,” the authors explained.

Adding that: “Temperature and mortality are linked not only at hot extremes, such as during heatwaves, but also at temperatures that are moderately hot. Owing to their more frequent occurrence, small temperature changes at mild or moderate temperatures can have larger health impacts than changes at extreme levels, such as during heat or cold waves.”

The researchers concluded that “unless adaptation is highly effective, it is less likely that heat risks to the U.S. population under high warming scenarios could be managed, a concept widely acknowledged in evaluation of future damages.

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“Our results provide an indication of the potential for warming to lead to large increases in the number of Americans who die prematurely each year due to heat exposure.

“This implies that significant efforts are required to increase the resilience of vulnerable populations in order to even maintain current (and unacceptable) levels of heat-related mortality.”



Study: Shindell, D., Zhang, Y., Scott, M., Ru, M., Stark, K., & Ebi, K. L. (2020). “The effects of heat exposure on human mortality throughout the United States”. GeoHealth, 3.