The Heat Attributable Mortality Tool in Spain and Its national impact
A new cross‑device application enables users to estimate and monitor deaths in Spain linked to high temperatures. During the previous summer, authorities reported 2,155 deaths attributed to heat exposure. This finding comes from the Supreme Council for Scientific Research (CSIC) and its collaborating teams.
A scientific collaboration involving the Institute for Environmental Diagnostics and Water Research (IDAEA/CSIC), the University of Valencia, and the Foundation for Climate Research (FIC) has built a web app that uses official data from the Climate Monitoring system and temperature records from the State Meteorological Agency (Aemet). The tool calculates mortality rates attributable to moderate heat, extreme heat, and the most intense heat events across the June‑to‑August period in Spain.
The application, named the Heat Attributable Mortality Rate (MACE) in Spain, is accessible through any web browser on a computer or other electronic device. The project team notes that daily updates provide a five‑year view of temperature‑related mortality. The year 2022 stands out with a high number of heat deaths, and the researchers also emphasize the intensity and duration of heat events, which during summers can span multiple weeks.
In a statement about the context of heat‑related mortality, the study highlights that the summer of 2023 marked the third highest level of deaths attributable to extreme heat, following notable heat periods in 2003 and 2022. The team relies on daily death counts and daily temperature data to perform its calculations.
Mortality linked to moderate heat is estimated by looking at days when temperatures lie between the daily minimum mortality level and the threshold for extreme heat. The threshold for extreme heat is defined as the 95th percentile, meaning that only about 5 percent of days between June and September in the past decade experienced higher temperatures. This approach helps quantify the portion of deaths connected to unusually warm conditions, separating routine seasonal variance from spikes tied to extreme heat.
Thus, the excess mortality associated with extreme heat is derived from days when daily temperatures exceed that high threshold. The CSIC notes that the excess heat component relates to the intensity of peak heat days, framing the app as a bridge between research and practical awareness of heat impacts on health. The goal is to translate scientific findings into actionable information for the public and policymakers—an important step toward protecting health in hot conditions.
Experts emphasize that while meteorological agencies and health ministries issue warnings about heat waves, they do not always quantify potential health effects or the combined impact of isolated extreme‑heat days. The researchers suggest that greater public awareness about the health consequences of extreme heat could motivate behavior changes guided by preventive actions outlined in national health plans. Practical recommendations include staying hydrated, seeking cool environments, limiting outdoor activity during the hottest parts of the day, wearing breathable clothing, and eating light meals to replenish minerals and salts.
At present, MACE calculates death rates for the summer season at a national level, with plans to incorporate regional differences and to consider vulnerable groups by age or gender in future updates. The team is actively working to broaden the data set to span May through October for the next version, expected in 2024, while continuing to refine its methodology and expand the range of variables analyzed. The effort represents a continued collaboration between research institutions and public health bodies to better understand and mitigate the health effects of heat.
Notes on methodology and data sources are provided by the researchers and their institutions, with ongoing updates to reflect new information as it becomes available. The project emphasizes transparency in data and interpretation and aims to offer a reliable resource for understanding heat‑related mortality trends. The public and policymakers can use these insights to improve heat‑related health planning and protective measures during warm seasons. (Source: CSIC and collaborating institutions, with data support from Aemet and national health authorities.)
For further information about the Heat Attributable Mortality Rate project and its evolving capabilities, readers should refer to the official communications and published research notes from the participating organizations. (Attribution: CSIC, IDAEA, University of Valencia, FIC.)