When the heat in Rome soars, the fountains provide a welcome respite.Credit: Andrea Ronchini/NurPhoto via Getty Images
The summer of 2023 has surpassed many temperature records in Italy, but by the end of the century it may be remembered as a mild one. According to an analysis published in 2019 by the European Union’s Copernicus Climate Change Service, Rome could have 28 heatwave days on average in 2080 if greenhouse emissions peak around mid-century, and 54 if they continue to grow, doubling by the end of the century. Milan will see a similar trend, with 30 heatwave days if climate mitigation policies are adopted and 60 if not.
Heatwaves are already longer and more frequent than a few decades ago. Last year in Rome the number of heatwave days was 11, around twice what was recorded in 2003, an especially hot year.
In 2021 a group led by Paola Mercogliano, climatologist at the Euro-Mediterranean Center on Climate Change (CMCC) reconstructed the evolution of the climate on a 2-kilometre grid during the last 30 years in Bologna, Milan, Naples, Rome, Turin, and Venice. The results of this work contributed to a report published by CMCC about climate risk in the six Italian cities.
According to that report, each of the last nine years was the hottest year observed since 1990 in all the cities. “Thirty years is the minimum time window to distinguish between normal climate variability and climate change,” she explains. The number of nights with temperature above 20°C, so-called tropical nights, have increased too.
“While rainfall projections are affected by larger uncertainties, climate models are much more accurate about temperatures,”, Mercogliano explains. “The evidence is strong, cities need to plan accordingly. Some of them have been doing so for several years, some others need to catch up,” she concludes.
A similar message comes from a preliminary study just published by the World Weather Attribution group of scientists. The study, which has not yet been peer-reviewed, considered the heatwave that struck in southern Europe between 12 and 18 July and indicates that without anthropogenic greenhouses gas emissions it would have been at least 1,000 times less likely. Moreover, scientists concluded that this kind of events are not at all rare in the current climate, having a return period of 10 years. If global warming reaches 2°C they will become even more common, with a return period between 2 and 5 years.
Since 2008, all six cities in the CMCC report have joined the European Covenant of mayors for Climate and Energy. The pact requires to approve a Sustainable Energy and Climate Action Plan, which details the interventions the city plans to put in place to reduce emissions (by at least 40% within 2030) and adapt to climate change effects. For some cities the plan has been an opportunity to map the risks posed by climate change, in particular heat and heavy rainfall. Bologna and Turin have the two most advanced risk assessment strategies and they are also considered examples at the international level.
Some other cities have relied more on the support and collaboration of research institutes and public agencies, as is the case of Rome.
“In January this year we signed two agreements with CMCC and ISPRA (Italy’s Institute for environmental protection and research) to conduct studies on hydrological stress and rising temperatures that will inform the adaptation strategy we are going to publish,” explains Edoardo Zanchini, who leads the Climate Office of the Municipality of Rome. “Partnering with research institutes will allow us to optimize resource allocation,” Zanchini explains.
This is already happening for the urban forestation initiative, funded by the Next Generation EU program, which should see nearly 560,000 planted in Rome by 2026. In 2015 a study by Roma Tre University and ENEA found that the Eastern part of the city is the most vulnerable to the impacts of climate change.
“In that area there are fewer green areas, and socioeconomic conditions are worse, limiting access to air conditioning. We will start from there.”
However, of the 130,000 trees expected for 2022, none have yet been planted. Other Italian cities are not doing better, as highlighted by a recent analysis by the Openpolis foundation.
