Heat-related deaths are on the rise, but they don’t have to be

The number of heat-related deaths recorded in the US jumped 117 percent between 1999 and 2023, it finds. These kinds of deaths are preventable, and had previously been on the decline. This study is likely the first to show an about-face in the US since 2016, the authors write.

Keeping people safe when temperatures spike is becoming more difficult in a warming world. Heatwaves are more frequent and more intense than they used to be. Authorities need to put appropriate safety measures in place to prevent more deaths in the future, the paper warns.

“As temperatures continue to rise because of climate change, the recent increasing trend is likely to continue,” it says. “Local authorities in high-risk areas should consider investing in the expansion of access to hydration centers and public cooling centers or other buildings with air conditioning.”

The research is based on data from the the Centers for Disease Control and Prevention (CDC) on deaths between 1999 and 2023. It counts deaths in which heat was recorded as an underlying or contributing cause — a total of 21,518 people who lost their lives over that time period.

The age-adjusted mortality rate started to increase significantly in 2016, growing 16.8 percent per year since then. That’s compared to a slight 1.4 percent decrease per year between 1999 and 2016. Heat-related deaths peaked in the US last year with 2,325 documented. 2023 also happened to be the hottest year on record for the planet.

We know that heat kills far more people each year than hurricanes, tornadoes, or other weather related disasters. And yet, official numbers can easily miss deaths related to heat that authorities may not have had the resources to investigate. Heat exposure can increase the risk of heart attack or stroke, for example, but that might not be named on a death certificate. Children, whose bodies are less efficient at cooling themselves down, and older people, who are more likely to have chronic health conditions, are most at risk during extreme or prolonged heat.

Policymakers and urban planners across the US are working to prevent those deaths and prepare for rising temperatures with climate change. The Biden administration has proposed federal heat protections for workers. Arizona, Miami, and Los Angeles now have chief heat officers charged with coordinating responses to extreme heat. Simple measures like keeping people informed ahead of a heatwave, making sure residents have safe places to cool down, and designing cities to trap less heat can all help save lives.