Recent findings from ISGlobal, the Barcelona Institute for Global Health supported by la Caixa Foundation, show that heated environments and reliable heating have contributed to lowering deaths linked to extreme temperatures in Spain. The study, published in Environment International, offers essential insights for professionals designing climate adaptation policies.
Temperatures rise while mortality declines
Spain, like many regions, has faced a warming trend. Across the country, average temperatures have climbed by about 0.36 degrees Celsius per decade, with summers warming even more quickly at roughly 0.40 degrees per decade. Yet the data reveal a counterintuitive pattern: heat-related deaths have gradually decreased, and cold-related deaths have also fallen, despite the hotter climate.
Understanding the factors that dampen human sensitivity to extreme temperatures is crucial for informing health policy and climate resilience measures. This perspective comes from Hicham Achebak, the study’s lead author, a researcher at ISGlobal and Inserm in France, who holds a Marie Sklodowska-Curie postdoctoral fellowship from the European Commission.
Effective social adaptations
The researchers examined demographic and socioeconomic factors to explain why deaths from heat and cold have declined even as temperatures rise. Findings indicate a growing use of air conditioning in Spain, which correlates with fewer heat-related deaths. At the same time, heating improvements contributed to fewer cold-related fatalities.
Specifically, air conditioning was linked to a 28.6 percent reduction in heat deaths and a 31.5 percent decrease in deaths during extreme heat between the late 1980s and early 2010s. Heating systems were associated with a 38.3 percent drop in cold-related deaths and a striking 50.8 percent reduction in extreme cold deaths. These trends would likely be more pronounced if not for a rising share of residents over the age of 65, a group more vulnerable to low temperatures.
The researchers conclude that the overall decline in temperature-related mortality during the studied period is largely tied to socioeconomic development in Spain rather than to specific measures such as heat warning systems.
Forty years of data
For their statistical analysis, the team gathered daily mortality data for all causes and climate data including temperature and relative humidity. The dataset covered 48 provinces on the Spanish mainland plus the Balearic Islands from January 1980 through December 2018. These data were linked to 14 contextual indicators encompassing housing, income, education, and other demographic and socioeconomic factors for the same timeframe.
Adapting to climate change
The study reinforces prior observations about heat-related deaths in Spain and underscores the value of air conditioning and heating as effective adaptation tools against heat and cold. Yet the authors note significant provincial disparities in air conditioning presence. Achebak points out that the cost of running cooling systems remains unaffordable for many households, highlighting inequality in resilience.
They also warn that widespread air conditioning could contribute to warming if electricity sources are not clean. As a result, other strategies are needed to cool urban areas, such as expanding green and blue spaces in cities. The researchers emphasize that their findings carry important implications for devising climate adaptation strategies and anticipate future projections on how climate change will influence human health. Joán Ballester, an ISGlobal researcher and study coordinator, echoes the call for informed action based on these insights.