Spain is on red alert for heat, not orange: why the maps of Health and the Aemet differ so much

Spain is currently experiencing extreme heat conditions, prompting health alerts across multiple regions. The situation has sparked confusion due to differing assessments between two major institutions: the Spanish Ministry of Health and the State Meteorological Agency (AEMET). These discrepancies have led to conflicting messages about the severity of the current heatwave, affecting how the public perceives the risk.

The Ministry of Health's Meteosalud system has issued red-level warnings for a significant portion of northern Spain, as well as several areas in central and southern regions. This system evaluates the physiological impact of heat on local populations, taking into account both average temperatures over three days and the level of adaptation of each area’s population to high temperatures. In contrast, AEMET's maps highlight temperature thresholds based solely on historical records, using maximum daily temperatures to determine warning levels—yellow, orange, or red. As a result, some regions deemed highly risky by Meteosalud appear less severe on AEMET's maps.

This divergence has raised concerns among experts who argue that the public might underestimate the danger due to reliance on AEMET's more widely recognized maps. For instance, while Meteosalud marks parts of Catalonia, Cantabria, and Madrid under red alert, these areas are shown in yellow or orange on AEMET's map. This discrepancy could lead to inadequate preparation and response measures, especially in regions where the health risks are higher than the meteorological indicators suggest.

Experts such as Julio Díaz, an investigator at the Institute of Health Carlos III specializing in climate change and health, emphasize the importance of considering the health impacts rather than just temperature readings. He highlights that the focus should be on how heat affects individuals living in specific areas, rather than simply noting where the highest temperatures occur. Despite this, AEMET's maps continue to dominate public discourse and media coverage, partly because they have been around for much longer than Meteosalud, which was introduced in 2024.

According to Héctor Tejero, responsible for Health and Climate Change in the Minister of Health’s office, efforts are ongoing to promote awareness of Meteosalud. While acknowledging that AEMET's maps still hold greater influence, he stresses that the Ministry of Health recommends relying on Meteosalud for its focus on public health. The newer system aims to provide more accurate guidance tailored to the health risks faced by residents in different regions.

A study published in 2024 further underscores the differences between the two systems. It found that in 52.5% of Spain's 182 climatic zones, the threshold for declaring a heatwave according to Meteosalud is lower than what AEMET considers necessary. This indicates that the health risks associated with heatwaves can be identified earlier and more accurately by incorporating factors beyond just temperature measurements.

As the heat continues, the challenge remains in ensuring that the public receives clear and consistent information about the risks they face. Both systems serve important roles, but the need for better communication and integration of health-focused data into public awareness campaigns becomes increasingly apparent. With the summer months ahead, the effectiveness of these alerts will play a crucial role in protecting vulnerable populations from the adverse effects of prolonged heat exposure.