In 2023, Europe experienced a record number of days where the heat felt was “extreme” for human bodies, due to temperatures above 35°C or 40°C and whose effects on organisms were accentuated by humidity, the absence of wind or the heat of urban concrete.
“The year 2023 reached a record number of days of “extreme heat stress”, that is to say days where the “felt temperature” exceeded the equivalent of 46°C”, details a report from the he European Copernicus Observatory and the World Meteorological Organization (WMO) published Monday April 22. This “heat stress” index takes into account the effect on the human body of temperature combined with other factors (humidity, wind, etc.).
In addition to heatwaves, the continent suffered many extreme weather events in 2023: two million people were affected by floods or storms, severe droughts affected the Iberian Peninsula and eastern Europe and the largest The continent’s largest forest fire has devastated 96,000 hectares in Greece, according to the annual report from Copernicus’ Climate Change Service (C3S).
These disasters cost €13.4 billion, 80% attributable to flooding linked to well-above-average rainfall.
Increased health risks
The report focuses particularly on the health consequences of heatwaves, while global warming makes summers increasingly hot and deadly. “We are seeing an upward trend in the number of heat stress days in Europe, and 2023 was no exception” with this new record, which is however not quantified in the report, said Rebecca Emerton, climatologist at Copernicus.
To measure this thermal comfort, the C3S and the WMO refer to the universal thermal climate index (UTCI, in English), which represents the heat experienced by the human body taking into account not only the temperature, but also the humidity, wind speed, sunshine and heat emitted by the environment, the effect of which is more pronounced in cities, where materials (concrete, tar, etc.) absorb more solar radiation.
The index, expressed as the equivalent of a “felt temperature” in degrees Celsius, includes ten different categories: from extreme cold stress (above −40°C) to extreme hot stress (over 46°C) by the absence of thermal stress (between 9°C and 26°C). Prolonged exposure to heat stress increases the risk of illness and is particularly dangerous for vulnerable people.
Current measures “soon to be insufficient”
On July 23, at the height of the heatwave, 13% of Europe was experiencing at least one degree of heat stress, an unprecedented level. The extreme heat mainly hit southern Europe, where air temperatures reached up to 48.2°C in Sicily, 0.6 degrees below the continental record.
The figures for excess heat-related mortality in 2023 are not yet known, but the report recalls that tens of thousands of people died in Europe during the sweltering summers of 2003, 2010 and 2022.
Caused by greenhouse gas emissions from human activity, global warming increases the intensity, duration and frequency of heatwaves. The phenomenon is particularly visible in Europe, which is warming twice as fast as the global average, whose climate is already at least 1.2°C warmer than before the industrial era.
Increased warming in Europe, combined with an aging population and increasing numbers of urban dwellers, will have “serious consequences for public health”, the report adds. And “current measures to combat heat waves will soon be insufficient” to deal with it.