A study by Maria A. Barceló and Marc Saez, from the Research Group on Statistics, Econometrics, and Health (GRECS) at the University of Girona (UdG), estimated the excess mortality attributable to extreme temperatures in Catalonia during the summer of 2022 and assesses how the risk of death from these extreme temperatures can be modified by other factors, particularly socioeconomic variables.

The summer of 2022 was one of the deadliest in recent decades in Spain. A study conducted by our research group reveals that, in Catalonia, almost half (49.4%) of the excess deaths recorded during those months can be directly attributed to extreme heat.

Until now, official estimates had calculated that only about 23% of these deaths were related to high temperatures. However, our analyses show that this figure may be an underestimate due to limitations of the models used.

The study, based on data from 2015 to 2022 and analyzed at the basic health area level, uses advanced statistical methods to reduce potential bias and more accurately capture differences between territories. In addition to heat waves, extreme maximum temperatures also increased the risk of death, especially among people over 65 years of age. Other factors that increased risk included high humidity, extreme minimum temperatures, and low income.

These results highlight the need to consider socioeconomic and spatial factors to better understand the impact of extreme heat on health. They also show the importance of using small geographic units and robust statistical models to obtain more reliable estimates.

The work reinforces the message that heat waves and extreme temperatures are a growing public health problem. Identifying the most vulnerable groups is key to designing prevention and adaptation policies that protect the population in the context of climate change.

This article is the first result of the CLIMA project ‘Geographic variability in the effect of extreme heat events on mortality in Catalonia. The case of Summer 2022’, whose Principal Investigator is Professor Dr. Maria A. Barceló.

Study reference

Barceló MA, Saez M. Assessing excess mortality and heat-attributable risk during the summer of 2022 in Catalonia, Spain: a Bayesian spatiotemporal analysis. Journal of Geographical Systems 2025, .https://doi.org/10.1007/s10109-025-00475-2.