Heat-Related Deaths Have Increased More than 100% in the Past Two Decades

The number of heat-related deaths in the U.S. increased 117% between 1999 and 2023, according to new research. The research comes after a summer of scorching temperatures and heat waves in the U.S.

Research published in the Journal of the American Medical Association on Monday found that the number of annual heat-related deaths jumped from 1,069 in 1999 to 2,325 in 2023. In total, there were 21,518 heat-related deaths in that 24-year period. In the last seven years alone, researchers found a sharp increase in heat-related deaths, coinciding with record-breaking high temperatures.

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Researchers analyzed data from the U.S. Centers for Disease Control and Prevention on all heat-related deaths recorded in the country from 1999-2023. The number of deaths fluctuated year-to-year, but researchers found that heat-related deaths increased by 16.8% per year from 2016-2023.

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“As temperatures continue to rise because of climate change, the recent increasing trend is likely to continue,” the researchers said in their analysis.

Researchers acknowledged that the number of deaths could be even higher, if causes of death were misclassified on death certificates.

This summer has seen several heat waves—the Midwest and East Coast were hit by a heat dome in June, with temperatures exceeding 100 degrees; and officials in California sent out alerts ahead of the Fourth of July long weekend, warning tens of millions of Americans of high temperatures. This past July was the warmest July on record for the globe in 175 years, according to the U.S. National Oceanic and Atmospheric Administration. And 2023 was the hottest year on record. 

Amid growing concern over the effects of climate change, climate experts and meteorologists have warned the public about the dangers of heat waves. Research has also shown that climate change can make extreme weather events—like hurricanes and wildfires—more intense and more frequent.

Another heat wave is expected to hit the Midwest this week, with temperatures reaching between 105-115 degrees.