Is Milan really the Italian city most affected by the abnormally hot weather? A preliminary study that estimated deaths in 12 European cities reports this

Between the end of June and the beginning of July, a severe heatwave was recorded across much of Europe, with temperatures well above seasonal averages. Europe's record on heat is held by an Italian town, Catenanuova, a Sicilian location that has reached 45 degrees this week, a temperature that is prompting residents to leave town and move elsewhere partly because of the resulting high cost of utility bills. Recently, the World Weather Attribution (WWA), an international research group of climate scientists, published the results of a preliminary study on the consequences of this extreme weather event, estimating that the number of deaths due to excessive heat has tripled. The analysis examined over ten major European cities, where the perceived temperature (also due to so-called “urban heat islands”) was particularly high. According to the report's estimates, in Milan alone this event may have caused more than 300 excess deaths. The Lombard capital would be the urban center with the highest estimated number of deaths – followed by Barcelona with around 280 and Paris with roughly 230, while in Rome there would have been at least 160 deaths. The analysis estimates that 65 percent of the total deaths recorded during the period from June 23 to July 2 were in some way directly linked to the heatwave. Moreover, 88 percent of the estimated deaths were over 65 years old – confirming a long-known trend: not only do deaths increase during extreme heat, but the most vulnerable groups (especially the elderly) are the most affected.

Founded in 2015, the WWA focuses on a new branch of climatology called “attribution science”, which investigates the links between climate change and extreme weather events, aiming to quickly determine whether climate change played a role. The scientific community now has enough data to contextualize specific weather events relatively quickly—albeit preliminarily—within the broader and more complex climate-related phenomena. In addition, the increased amount of data has made it possible to definitively confirm what was hypothesized decades ago with the first climate prediction models: namely, that the rise in the Earth’s average temperature (caused by greenhouse gas emissions largely due to human activities) is a key factor in increasing the frequency and intensity of extreme weather events. Storms, prolonged droughts, below-average temperatures in some regions, and, precisely, heatwaves in others: these are just some of the extreme weather events made more likely by climate change, which in turn contribute to uncontrollable wildfires, floods, or droughts in various parts of the world, with severe consequences for local populations.

However, weather events and climate events should not be confused. Scientists strongly emphasize the distinction between “weather” and “climate” to prevent premature conclusions from being drawn from isolated extreme events without sufficient data. The former involves the study of specific atmospheric phenomena confined in time and space, while the latter includes more complex analyses of how weather patterns affect an area over decades. In recent years, studies on individual atmospheric phenomena have improved thanks to the effectiveness of models used to assess climate changes, also due to the ability to gather much more information and evidence on weather events in different parts of the world.

The year 2024 was the first in which the 1.5 °C threshold set by the Paris Climate Agreement – the most important international treaty to combat global warming – was exceeded for such a prolonged period. This threshold had long been expected to be surpassed, especially since the past year, like the last decade, was the hottest ever recorded. The reference point for evaluating the trend of the global average temperature is the late 19th century, when industrialization levels were very low and, consequently, the emission of large amounts of carbon dioxide—the main greenhouse gas produced by human activities—was minimal. The primary cause of the rise in global average temperature is, in fact, the accumulation of greenhouse gases, mainly due to the use of fossil fuels. At this rate, there is a risk in the future of also exceeding the 2°C threshold, established by the Paris Agreement as the maximum limit to avoid even more catastrophic consequences linked to climate change. An additional half degree would further increase the likelihood of increasingly frequent disastrous weather events – including the same heatwaves, with real consequences for many people.