In a new study led by the Barcelona Institute for Global Health (ISGlobal), researchers have made a startling revelation about the impact of high temperatures on mortality in Europe last year. The study reveals that the number of heat-related deaths in Europe may have exceeded 70,000 during the summer of 2022.
In a previous study, the ISGlobal team had estimated that 62,862 premature deaths in Europe were linked to heat in 2022. This estimate was based on epidemiological models applied to weekly temperature and mortality data across 823 regions in 35 European countries. However, the experts acknowledged that this approach likely underestimated the true impact.
In the new study, the researchers aimed to develop a theoretical framework to quantify errors in mortality estimations caused by using aggregated data, such as weekly or monthly temperature and mortality records.
The team compiled daily temperatures and mortality records from 147 regions in 16 European countries, and compared mortality estimates across various levels of data aggregation: daily, weekly, bi-weekly, and monthly.
Compared to the daily model, the models using longer aggregation periods had significantly underestimated the effects of heat and cold on mortality.
For instance, during 1998-2004, the daily model estimated an annual mortality of 290,104 for cold and 39,434 for heat-related deaths, while the weekly model underestimated these figures by 8.56 and 21.56 percent, respectively.
“It is important to note that the differences were very small during periods of extreme cold and heat, such as the summer of 2003, when the underestimation by the weekly data model was only 4.62 percent,” explained Joan Ballester Claramunt, an ISGlobal researcher who leads the European Research Council’s EARLY-ADAPT project.
However, the differences in mortality estimates were still significant enough to warrant a revision of the mortality burden attributed to the 2022 heatwave.
By applying this new methodology, the researchers concluded that their earlier study had underestimated the 2022 heat-related deaths by 10.28 percent, revising the actual figure to 70,066.
This study highlights the severe impact of extreme temperatures on public health. The results emphasize the importance of improving data collection and analysis methods for more accurate and timely responses to rising temperatures.
“In general, we do not find models based on monthly aggregated data useful for estimating the short-term effects of ambient temperatures,” explained Ballester. “However, models based on weekly data do offer sufficient precision in mortality estimates to be useful in real-time practice in epidemiological surveillance and to inform public policies such as, for example, the activation of emergency plans for reducing the impact of heat waves and cold spells.”
Heat-related deaths, a critical concern in the context of global climate change, represent a growing challenge for public health systems worldwide. As global temperatures rise, the frequency and intensity of heatwaves are increasing, leading to a significant upsurge in heat-related mortality.
This phenomenon is particularly evident in regions like Europe, where historically milder climates are experiencing unprecedented temperature highs.
Heat-related deaths occur when the body, overwhelmed by excessive heat, is unable to regulate its internal temperature. This can lead to a cascade of health issues, including heatstroke, dehydration, and exacerbation of pre-existing health conditions like cardiovascular and respiratory diseases.
Vulnerable populations, such as older people, children, and those with chronic illnesses, are at a higher risk.
The impact of heat on mortality is not just direct; it also indirectly affects health through worsening air quality, increasing the prevalence of vector-borne diseases, and exacerbating mental health issues.
Urban areas, with their “heat island” effect due to dense infrastructure and limited green spaces, often record higher temperatures and, consequently, higher heat-related health issues.
In Europe, the recent increases in heat-related deaths have prompted a reevaluation of public health strategies. Governments and health agencies are now focusing on improving warning systems for heatwaves, establishing public cooling centers, and enhancing public awareness about the dangers of high temperatures.
These efforts are crucial in protecting the most vulnerable populations and mitigating the overall impact of heat on public health.
Furthermore, there’s an increasing emphasis on the long-term strategies to combat climate change and its effects. This includes urban planning initiatives to increase green spaces and improve building designs for better natural cooling, as well as broader environmental policies aimed at reducing carbon emissions and slowing global warming.
The study is published in the journal The Lancet Regional Health – Europe.
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