This story is part of Record High, a Grist series examining extreme heat and its impact on how — and where — we live.

More than 61,000 people died because of record-breaking heat in Europe last year, according to a new study published Monday in the journal Nature Medicine. The summer of 2022 was the hottest period ever recorded on the continent.

Researchers looked at heat-related deaths during the summer of 2022 and found that women in Europe made up more than 60 percent of deaths and that adults over the age of 79 made up over half of all deaths. Study authors said that this is a jump of more than 25,000 heat-related deaths from the period spanning 2015 to 2021. 

Italy, Spain, and Portugal had the highest mortality rates linked to the heat, emphasizing the vulnerability of Mediterranean countries to heat-related mortality. 

“Our study highlights the accelerated warming observed over the last decade, and emphasizes the urgent need to reevaluate and substantially strengthen prevention plans,” said Marcos Quijal, a co-author of the paper. “These trends also suggest that without effective adaptive responses, Europe could face a significant increase in premature deaths each summer, reaching more than 68,000 by 2030 and over 94,000 by 2040.”

So far this summer, the trend has continued — last week, the planet experienced its hottest seven-day stretch in recorded history.

Average surface temperatures have been rising for years due to climate change, but this summer’s extreme heat has been rapidly breaking records. In addition to average hotter temperatures, the reemergence of the weather phenomenon known as El Niño is poised to drive up temperatures even more. 

The human body is not meant to survive long periods of extreme heat, mostly because it already produces heat from daily activities like circulating blood and digesting food. Sweating can be an essential tool to cool down and prevent overheating, but when humidity levels are also high the body can’t produce the adequate amount of sweat needed to manage its temperature. 

While temperatures throughout Europe were sky-high during the summer of 2022, the average daily temperature in southwestern Europe that year was the highest recorded since 1950, according to the European State of the Climate report for 2022. 

Older people can be more vulnerable to heat stress because of cultural differences — they may not hail from a warm region and might not know how to adjust — and biological ones, as aging can impact the body’s ability to regulate temperature. 

Justin S. Mankin, a researcher at Dartmouth University who was not involved with the study, said that heat waves like the one in Europe last summer are part of a trend that has been worsening for years. As the planet continues to warm, extreme heat will only get worse. 

“You could throw a dart at the map and probably find a heat wave somewhere,” said Mankin. 

Though the conditions of last summer’s European heat wave and 2021’s heat wave in the U.S. Pacific Northwest were extreme, Mankin says there is a lot of science to support the fact that temperatures won’t rise in a straightforward fashion. 

[Read more about the science behind climate-change-driven heat waves.]

“We have a really good understanding of why the likelihood of extremely rare heat events should increase nonlinearly with warming,” said Mankin. 

The study authors noted that last year’s heat wave bears a striking resemblance to the 2003 heat wave in Europe that killed 70,000 people, which in France led to the resignation of the nation’s health chief and spurred the country to redesign their approach to heat. 

Mankin also noted that despite the astounding figures, there is a lot that researchers can’t account for –– including a completely accurate total death count. 

“In all likelihood, these death counts are probably an undercounting to some extent,” said Mankin. 

This story was originally published by Grist with the headline More than 61,000 died from heat in Europe last summer — and experts think that’s an undercount on Jul 11, 2023.