The heat-related mortality It has been identified as one of the greatest climate extremes posing a threat to human health. Current research focuses primarily on how this mortality increases as the average global temperature rises.
However, these changes are being strongly promoted extreme events that are becoming more frequent and intense, hitherto unseen, reaching uncharted territory.
This is according to a new study published in nature communicationled by Swiss research centers and in which the researcher Dominic Royé from the Foundation for Climate Research (FIClima) participates, where the Changes in the frequency of extreme heat events and that associated mortality.
Through a probability analysisOn the one hand, the authors summarize the connections between heat and mortality 748 locations in 47 countriesand on the other hand data from large amounts of climate modelsto identify likely past and future high-impact summer events.
Therefore, a heat mortality event of once every 100 years would be expected in most locations in 2000 or early this century every 10 to 20 years in 2020 or in today’s climate.
Under these conditions it is to be expected that Return periods are shortened even less warming 1.5°C and 2°Cwhere the heat mortality extremes of past climates will eventually become normal if not adapted.
This is to be expected given that the effects are not linear, both for the new climate extremes and for the heat vulnerability of the population unprecedented impact on human healthespecially among the most disadvantaged, assuming that there is no adjustment.
The study’s conclusions underscore the urgent need for strong containment and adaptation to reduce the impact on human life.
The examples of Paris and Barcelona
As an example: In the summer of 2003, the excess mortality was 2,700 people Parisit was a very rare event, occurring once every 100 years. In the current climate, it is expected to occur every 18 years and every four years in a world with global warming of 2°C.
At the same time, mortality caused by future summers in Paris with unprecedented intensity doubles in a 1.5°C world and nearly triples in a 2°C world without adjustment.
In Spain, an extreme summer event that could occur every 100 years in the recent past, currently in Barcelona, has increased its frequency to every 10 years in 2020, even with a projected global warming of 2°C 1 every 2 years.
Thus, heat-related mortality from a secular event would increase from 7.4% in 2020 to 13% in a world with global warming of 2°C.
With this approach it is possible to quantify the direct potential impacts of climate change in human health. City-level results are more practical for decision-makers such as health authorities.
This information can also be very useful for decision makers to prepare for extreme conditions of the future. In this way it will be possible to create the possibility of better adaptation and reduction of vulnerability, which is the most important end use of the study.
Changes in the return periods of a secular event at the 748 locations. Changes in return periods for climate 2020 (1.2 °C warming, a), at 1.5 °C warming (b) and at 2.0 °C warming (c) compared to the risk in the climate of the year 2000 (0 .7 °C warming). ). / Samuel Lüthi et al./Nat. commune
Samuel Lüthi et al. “Rapid increase in risk of heat-related mortality” nature communication, 2023