We are saddened when hearing about persons dying in floods, tornadoes, and other natural weather disasters. The numbers seem so high. But...it turns out the biggest killer each year is heat. Extreme heat kills more people most years than hurricanes, floods, and tornadoes combined.
Extreme heat events are on the rise globally (yup, climate change) and so the number of people dying are increasing. For example, the recent heat wave across Europe, when temperatures surged higher than 100 degrees Fahrenheit, is thought to have killed thousands of people. Especially since in many of the areas hit by the extreme heat people don't have air conditioning in their homes.
A quick analysis of heat-related deaths by researchers at the Imperial College London found that human-induced climate change intensified the European heatwave between June 23 and July 2, 2025 and tripled the number of heat-related deaths. They found that about 2300 people may have died from the extreme heat over the 10 day period across the 12 European cities they looked at, but that over all Europe there could have been tens of thousands of deaths. People over 65 accounted for a majority (88%) of the deaths.
Each year in the US, heat kills more people than any other type of extreme weather.
The following article was written last year, but it still applies since each year is getting hotter. Note that 2024 was hotter than 2023, which was the final year of the heat-related death analysis. NY Times: Heat Deaths Have Doubled in the U.S. in Recent Decades, Study Finds
As dangerous heat bears down on the central and eastern United States this week, a new study shows heat-related deaths across the country are on the rise.
While 2023 was the hottest year on record and led to at least 2,325 heat-related deaths in the U.S., more than 21,518 people have died from heat since 1999, according to a study published Monday in JAMA, the journal of the American Medical Association.
Heat kills more people in the United States than any other type of extreme weather, according to researchers. The study noted a 117 percent increase in heat-related deaths over the past 24 years, with a significant upswing since 2016.
The Southwest has seen a disproportionate amount of those deaths. About 48 percent of heat-related deaths took place in Arizona, California, Nevada, or Texas, Dr. Howard said. That detail was not included in the study, he noted.
Warming can be deadly around the globe. Heat contributed to 47,000 deaths in Europe last year [2023]. according to a recent study. That number could have been even higher if air-conditioning, better public information and other strategies had not been implemented across the continent, researchers found.