2023-04-27 16:00:00
Increasing drastic change in temperature wreaks real havoc on our body. For example, the lungs and hearts of heat wave victims are subjected to a significant overexertion to maintain the pressure of blood vessels that dilate when we are subjected to an intense rise in temperature. If left unchecked, your blood pressure will eventually drop dramatically, which can lead to dizziness and slurred speech. Then, the collapse of the circulatory system can trigger failure of vital organs, such as the bladder, heart or kidneys, which in extreme cases can lead to death.
According to a study published in the specialized magazine Nature Climate Change, until a third of the deaths attributable to the increase in temperature are caused by humans. This is the conclusion reached in a joint investigation by the London School of Hygiene & Tropical Medicine (LSHTM) and the University of Bern using data frome 732 locations in 43 countries around the world between 1991 and 2018. The research shows for the first time the real contribution of anthropogenic climate change to the increase in mortality as a consequence of heat.
Madrid, among the most affected cities
According to the researchers, the highest rates of mortality from human-induced heat occurred in Central and South America (up to 76% in Ecuador and Colombia) and in Southeast Asia (with figures ranging from 48 and 61%). The absolute values reflect the extent of the tragedy: a total of 136 additional deaths per year in Santiago de Chile (44.3% of total heat-related deaths in the city), 189 in Athens (26.1% of the total), 172 in Rome (32%), 156 in Tokyo (35.6%) and 177 in Madrid (31.9%). Other regions with high death peaks were Bangkok (53.4%), New York (44.2) or Ho Chi Min City (48.5%).
Mortality due to human-induced heat in the city of Madrid was 177 people, 31.9% of the total related to excess heat.
The human impact on heat waves
Global warming affects human health on several fronts. It impacts directly through the spread of forest fires, unleashing extreme weather events, facilitating the spread of vector-borne diseases… But the scientists found the dimensions of human-induced heat waves on population mortality and morbidity, a scenario that will worsen as temperatures rise even more. The study, say those responsible, it is the first evidence of an effect that until now had not been quantified.
The authors of the study assure that their conclusions are further proof of the need to mitigate future heat waves with measures aimed at protecting the population from this thermal overexposure. “We know that warming has accelerated in recent years, and that perhaps the rate of adaptation of the population is being much slower than that of the increase in temperatures. Therefore, we believe it is necessary to strengthen the adaptation systems in force to be able to face the progressive increase in temperatures”, he explains by email to National Geographic España Dr. Ana M. Vicedo Cabrera, lead author of the study.
Scenarios with and without contamination
To carry out the study, the scientific team focused on man-made global warming through a “detection and attribution” study that identifies and attributes the phenomena observed to the climatic changes caused in a certain time. Specifically, the team examined simulated past weather conditions under scenarios with and without anthropogenic emissions. This allowed the researchers to separate warming and the health impact related to human activities. Thus, they determined that heat-related mortality data was defined as the number of deaths attributed to heat, occurring at exposures above the optimal temperature for human health, which varies from location to location.
Greater impact on low-income populations
Curiously, the populations that live in countries that polluted little in the past and with an average income of medium or low, are among those most affected by excess deaths.
Although the authors acknowledge the limitations of the research, since it is impossible to include places from all regions of the world, emphasize the importance of the study when defining future environmental policies. “Our results are a sign that climate change is a reality and that it is already affecting the health of the population. They suggest that, therefore, it is necessary to implement urgent and ambitious mitigation and adaptation measuresto attenuate global warming and reduce the number of deaths due to heat in the medium-long term,” concludes Dr. Vicedo.
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