Heat-related deaths to rise by up to 7.7% by end of century if climate change is not halted

BarcelonaThere are several scientists who point out that as long as greenhouse gas emissions cause an increase in global temperatures, people's health will be at risk. Now, however, a study by the Institute for Global Health (ISGlobal), a centre promoted by the Fundació "la Caixa", reveals that if the necessary measures to mitigate the effects of climate change are not taken urgently, the number of deaths from heat will grow exponentially in the coming decades. The research, published in the scientific journal The Lancet Planetary Health shows that global warming will inevitably lead to a decrease in cold-related mortality and an increase in heat-related deaths, an effect that could be controlled if measures are implemented to reduce the number of CO2 emissions into the atmosphere.

The study, which has analysed mortality and temperature data recorded between 1998 and 2012 in 16 European countries with a total of 147 regions, concludes that more than 7% of all deaths recorded in this period were related to temperature. Moreover, during these years, cold temperatures had an impact on mortality up to ten times higher than warm temperatures. This trend, however, is reversed in the projections made by the study based on the combination of four climate models, which show that heat-related deaths will exceed cold-related deaths by mid-century, especially in areas such as the Mediterranean: "The incidence of this phenomenon is uneven, since the Mediterranean is an area more vulnerable to heat", says Marcos Quijal, a researcher at ISGlobal and one of the main authors of the study.

Three impact scenarios

The research projections vary according to three different scenarios: a more optimistic scenario -in which there would be a significant reduction in greenhouse gas emissions-, a moderate one -in which a stable trend in emissions would be expected-, and a final scenario, the most pessimistic of all, in which emissions would continue to increase at the same rate as they have done so far and global temperatures would rise by up to five degrees. It is precisely this last scenario that worries the authors, since it would imply that, without applying any mitigation measures, this increase in temperatures would translate into an increase in mortality in the different regions. "This is important because depending on the measures taken, one scenario or another will occur and the lethal consequences may vary".

If the data is broken down by region, and we take the worst-case scenario, in Spain the increase in mortality due to high temperatures in the middle of the century - that is, in just 30 years - would be between 1.3% and 4.5%, while this figure would increase by between 2.5% and 10% by the end of the century. Catalonia, moreover, would be the third autonomous community in which heat-related deaths would increase the most if measures to control the effects of climate change were not applied: this type of death would increase by 7.7% by the end of the century and by 2.8% in less than three decades. It should be borne in mind that the predictions of the study have been made on the basis of epidemiological data from the whole population, both in urban and rural areas.

The researchers point out that the projections indicate a large increase in deaths as a result of extreme heat, although they do not delve into the analysis of extreme heat waves, such as the one experienced in Canada last week. The study assures that in the scenario that does not adapt to the climatic emergency mortality is accentuated and it urges to take measures to avoid it. "Our results confirm the urgency of adopting global mitigation measures, which if only adapted in specific countries or regions will not be effective", says Joan Ballester, researcher at ISGlobal and author of the study, who assures that acting - or not - in the face of climate change makes us more vulnerable to heat.