Extreme heat likely cause of almost 3,000 excess deaths in Catalonia last summer

Catalonia recorded 17,458 deaths between June 1 and August 28 last year, 2,705 (15.5%) more than expected, according to a report from the health department published this week. 

The most likely cause of the excess deaths is extreme heat, while the impact of coronavirus "seems more limited," researchers say, as most of the population were already vaccinated.  

Temperatures were unusually high last summer, with 42 days of heat waves. 

The first wave, between June 12 and 18, was the second earliest on record. The second and third heat waves, from July 9 to 26 and from July 30 to August 15, were among the longest on record. 

The second heat wave was also the most extensive and intense registered in Spain. 

"Extraordinarily high" excess mortality 

"We had extreme heat almost the entire summer," Anna Mompart, a deputy director general at the health department and one of the authors of the report – Excess Mortality in Catalonia, June-August 2022 – told the Catalan News Agency (ACN). 

The report found that Spain suffered an "extraordinarily high" excess mortality from mid-July to mid-August, especially among people over 75 years old. 

Other countries, including France, Italy and England and the German state of Hesse also suffered from high excess mortality, which is the difference between recorded and expected deaths according to a baseline reference. 

Correlation with heat waves  

After combining health data with data from the Catalan network of automatic meteorological stations, researchers observed a relatively clear correlation between temperature and deaths: "The increase in temperatures means an increase in deaths," the report states. 

Mompart says that the study methodology did not enable the researchers to establish causal relationships but that, in accordance with the data collected, they can conclude that "heat waves, and related pollution, drought, humidity and pollen, affected the population and led to this excess mortality." 

Gender and postcode inequality 

Excess mortality was higher in women (8.8%) than men (5.1%), according to the study, which researchers put down to two factors: first, more women are elderly than men, and second, women have a lower socioeconomic level on average, meaning less access to resources to deal with extreme heat, such as air conditioning. 

Excess deaths were also higher in rural areas and in more disadvantaged urban areas, but Mompart attributes this to demographic differences – ie there are more elderly people in rural areas and elderly women in particular "live in situations of greater vulnerability," with "lower earnings." 

The authors of the report call on authorities to "prioritize the analysis of the impact of climate change on the health of the population."