Heat is the deadliest weather phenomenon

While the peak of the heat wave is reached this Monday and Tuesday in France, Meteo France evokes a situation of absolute vigilance”. At the same time, in the United Kingdom, the organization weather report national, the Met Office, declared an emergency situation posing a risk to the lives of citizens. More 1,000 people have already died in Portugal and Spain because of the heat wave that has been going on for a week: about 700 in Portugal and 400 in Spain. In France, no figures have yet been communicated.

In France, each major heat wave kills thousands

Contrary to what one might think, high heat does not only cause thousands of deaths in India, Pakistan or Africa. In Europe, as in the United States, the heat is the weather phenomenon that kills the most people on average, ahead of floods, extreme cold and hurricanes (for the United States). In the rest of the world, the cold remains the deadliest phenomenon, but the trend is changing gradually.

Remember that in 2003, the historic heat wave of 1^er August 15 had caused the death of 70,000 people in Europe, including 15,000 to 20,000 in France. As often, it is necessary to wait for the arrival of major disasters for the creation of specific alert systems. This is how “heat wave” (but also “extreme cold”) vigilance was added to the list of weather alerts from Météo France in 2004, after the thousands of deaths linked to the 2003 heat wave. In 2019, the historic heat wave which raised the temperature to 46°C in Vérargues in the Hérault caused the death of at least 1,500 people in France, more than any other weather phenomenon since the 2003 heat wave.

Although the management of extreme weather hazards has obviously improved, the UN specifies that everywhere in the world, the observation is the same: heat waves are the weather phenomena which worsen the most, but also those for which the countries are the least well prepared. In England, projections estimate that 2,000 people a year will lose their lives due to heat waves by 2050, while the country has until now felt very little concerned by the increase in temperatures.

Heat-related mortality is vastly underestimated

According to the World Health Organization, 166,000 people died worldwide due to heat between 1997 and 2017, a figure probably very underestimated due to the many indirect deaths linked to this weather phenomenon and possible health complications, not necessarily well understood or listed in certain countries. According to the UN, the global increase in temperatures will cause 250,000 more deaths between 2030 and 2050, and not only due to heatstroke, but also due to the diseases and lack of food that high heat causes. Some research organizations mention much higher heat-related mortality figures: according to a study of The Lancetthe heat is said to have killed at least 356,000 people worldwide in 2019.

In addition to being able to trigger heat stroke (when body temperature exceeds 40°C), heat waves can also causestrokeof thrombosis or of cardiac problem. Associated with pollution, they lead to or aggravate respiratory problems. When heat is combined with other hazards, such as air pollution or water, or an illness already in progress, the deaths are not necessarily attributed to the heat wave, which suggests that the number of heat-related deaths, including in Europe, is much greater than the figures officials.