The population of Spain has adapted to increasingly extreme temperatures since 1989

The number of deaths due to heat has decreased in Spain despite being one of the Mediterranean countries most affected by the increase in temperatures and heat waves. Source: Joan Costa

The population of Spain has adapted progressively to extreme temperatures, both cold and hot, since 1989 for the cold and since 2009 for the heat. This is one of the results of a study prepared by the Spanish National Research Council (CSIC), that provides quantitive estimates at the national level of the long-term adaptation of the population to non-optimal temperatures in Spain in the last 40 years. The work, which analyses more than 14 million deaths, has been published in the Environmental Health journal.

“Currently, Spain is one of the countries most affected by the increase in temperatures and heat waves within the Mediterranean region. Over time, people tend to adapt to new conditions, wheather favourable or unfavourable. However, adequately assessing the adaptation to non-optimal temperatures in the population is complicated, since it requires the joint evaluation of several epidemiological indicators”, explains Dariya Ordanovich, researcher from the Institute of Economy, Geography and Demography of CSIC.

According to the data obtained, the mortality due to cold showed a significant reduction, whereas the risk of mortality attributable to heat showed a much smaller reduction and is only observed at the end of the observation period. The minimum mortality temperature, in which the risk of death is lower, decreased until the most recent decade, between 2009 and 2018, when the optimum temperature threshold increased by almost 2°C in Spain. “The minimum mortality temperature is frequently used as an indicator of the speed of adaptation. The logic is that if populations become less susceptible to heat, an increase of this optimum temperature can be expected over time. In addition, it is also crucial to measure the reduction in mortality risk due to non-optimal temperatures”, declares Ordanovich. The study shows a wider range of optimal temperatures both cold and hot.

“We could consider that the adaptation to non-optimal temperatures in Spain has been taken place progressively. First, since 1989 for the cold and 20 years later, since 2009, for the heat. Despite this adaptation, there remains a considerable health risk from extreme heat, as seen during the summer of 2022”, says the researcher  Aurelio Tobías, from the Institute of Environmental Assessment and Water Research (IDAEA-CSIC).

According to Diego Ramiro, director of the Institute of Economy, Geography and Demography, Spain must establish as a priority to continue with the development of a climate change adaptation strategy. “The increase of temperature and the greater protection and adaptation have made mortality related to cold waves the ones thas has reduced the most. In the current context of inflation and where the cost of energy is higher, it can mean that in periods of more intense cold, the most vulnerable population, for instance, elder people, see their possibilities of protection limited against low temperatures and that produces an increase of health problems in this population. But this is something that we will only be able to analyse in detail in the coming months, when the data is available”, concludes Ramiro.

Ordanovich, D., Tobías, A., Ramiro, D. 2023. Temporal variation of the temperture-mortality association in Spain: a nationwide analysis.  Environmental Health volume 22, Article number: 5 (2023)

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