Zurich [Switzerland]: The old, the ill, and the poor are especially vulnerable to the devastating effects of heatwaves like the one we are presently experiencing. One of the deadliest natural disasters in recent memory, the 2003 heatwave that saw temperatures in Europe exceed 47.5 degrees Celsius claimed between 45,000 and 70,000 lives in a few weeks.
The emergency rooms in the cities were overflowing, the forests burnt, and the harvests in the fields perished. Around 13 billion dollars worth of costs were incurred globally. However, compared to other climate-related events, the public continues to be less informed about the dangers of heat waves. According to a study that was written in the journal Nature Communications, this is an issue. Heatwaves similar to the one we experienced in 2003 might become the new standard in the coming years.
Epidemiology and climate modelling combined: Researchers from the Institute for Environmental Decisions at ETH Zurich collaborated with an international group of epidemiologists on the study. Since 2013, they have been systematically collecting data on daily heat-related excess mortality for 748 cities and communities in 47 countries in Europe, Southeast Asia, Latin America, the U.S. and Canada. The researchers used this dataset to calculate the relationship between the average daily temperature and mortality for all 748 locations. From this, they were able to establish each location’s ideal temperature, where excess mortality is at its lowest. In Bangkok, for example, this value is 30 degrees Celsius, in São Paulo 23, in Paris 21 and in Zurich 18 degrees Celsius.
Physically plausible weather extremes modelled: Every tenth of a degree above this ideal value increases excess mortality. “Not all heat is the same,” explains Samuel Lüthi, lead author of the study and doctoral student under David Bresch, Professor for Weather and Climate Risks.