Among the many effects of climate change on human health is increased mortality and morbidity from extreme heat events. In addition, high temperatures negatively affect the well-being of the population and cause high health costs. However, quantifying these impacts in an objective and measurable way is complex, and until now, no large-scale empirical data was known.
Now, a work published in the journal Nature Climate Change shows the real contribution of man-made climate change in increasing mortality risks due to heat, and reveals that between 1991 and 2018 more than a third of all heat-related deaths can be attributed to global warming. The work was carried out by an international team of researchers who used data from 732 locations in 43 countries to estimate the mortality burden associated with additional exposure to heat resulting from recent warming induced by anthropogenic activity.
Across the study countries, the researchers found that 37% (with a variability range of 20.5 to 76.3%) of heat-related deaths in the hot season can be attributed to anthropogenic climate change and that the increase in mortality is evident on all continents. The burdens varied geographically, but ranged from tens to hundreds of deaths per year in many parts of the world. Interestingly, populations living in low- and middle-income countries, which are responsible for a small part of anthropogenic emissions in the past, are the most affected , with a higher mortality ratio in Central and South America, and South- East Asia.
Spain, one of the most affected countries
“Spain is one of the southern European countries where the most warming has been observed. In relative terms and during the period studied, Spain had 30% of heat-related deaths attributed to human-induced climate change ”, indicates the CSIC researcher and author of the study Aurelio Tobías. “The number of deaths from heat related to climate change is 704 per year in the summer period in the provincial capitals of Spain, specifically, 177 in Madrid, 94 in Barcelona and 39 in Seville,” Tobías specifies.
The more global warming, the more deaths
Epidemiological research focused on human-caused global warming, in a study called “detection and attribution” since it identifies and attributes the observed phenomena to changes in climate and weather. Specifically, the researchers examined projected past climate conditions in scenarios with and without anthropogenic emissions , so they were able to separate warming and human-related health impacts from natural trends.
“We anticipate that the proportion of deaths related to heat will continue to grow if we do not do something to stop climate change or if we do not adapt,” says Ana M. Vicedo-Cabrera, researcher at the University of Bern (Switzerland) and first author of the study. . ” So far, the average global temperature has only risen by about one degree Celsius, which is a fraction of what we could face if emissions continue to rise uncontrollably .”
Heat, pollution, allergies …
According to the WHO, extreme temperatures contribute to deaths in several ways: directly from cardiovascular and respiratory diseases, especially among the elderly, but also indirectly. For example, high temperatures cause an increase in the levels of ozone and other air pollutants that in turn aggravate the aforementioned cardiovascular and respiratory ailments and, on the other hand, allergies to pollen and asthma are also worse with extreme heat.
According to the IPCC, by 2100, the combination of high temperature and humidity in some areas during certain periods of the year is expected to compromise normal human activities such as producing food or working outside. For the authors of this work, their findings support the urgent need for more ambitious mitigation and adaptation strategies to minimize the impacts of climate change on public health. “The message is clear: climate change will not only have devastating impacts in the future, but we are already experiencing the dire consequences of human activities on our planet,” warns lead author Antonio Gasparrini.
Referencia Vicedo-Cabreraet al. 2021.The burden of heat-related mortality attributable to recent human-induced climate change. Nature Climate Change. DOI: 10.1038/s41558-021-01058-x
Source: CSIC
