There are dozens of projects underway around the world to mitigate the heatwave. But not all of them have proven effective because every city is different from the others. What is certain is that it is useless to create eco-anxiety and even shout about the emergency
Five days of heatwave and the climate crisis’s cassandras are unleashed again. They accuse the deniers, the government, even those they meet on the street in a slightly dated car; they try (and also succeed) to create that new disease called eco-anxiety, especially in the most fragile, easily impressionable classes of citizens, ultimately generating waves of social envy. The fault, obviously, according to them, would be those who are wealthy enough to own an air conditioner, those who use the car to go to work or tolerate the heat without panicking.
What would it really take to mitigate the summer heat
Everyone is good at alarming, less so at making truly useful decisions to mitigate the heat, especially in cities. There is talk of increasing the greenery, but then trees and lawns must be chosen well, cared for, and this increases costs. More outdoor swimming pools are needed, but they haven’t been built for decades; less asphalt and more grass, but then even the streets that become pedestrian end up being tiled, albeit perhaps with athermal elements (which don’t get too hot). Naturalistic engineering works would also be useful, such as rain gardens and drainage trencheswhich collect and filter rainwater in a natural way, also avoiding sudden loads on the sewer system when violent downpours break out.
However, with a little intellectual honesty we must admit that in the last twenty years, completely glazed buildings have been built in large numbersoften passed off as ecological, in which survival is impossible without the continuous supply of electricity for heating or cooling. The walls and roofs must comply with the heat dispersion limits imposed by the regulations; even offices, often characterized by large continuous windows that can cause strong overheating, a perfect greenhouse effect.
Virtuous examples already exist
It therefore becomes essential to provide solar shading and the installation of selective glass so as not to increase the work of the air conditioning system.
Yet history teaches and it is sufficient to observe how they were built farmhouses in the Po Valley (thick walls and small windows), or even the dammusi of Pantelleria, to understand that our ancestors knew a lot. According to studies conducted in the United States, in particular those by the US Geological Survey, with the correct installations, over 4°C can be recovered in urban areas. To achieve this, however, it is necessary to replace the asphalt surface with thermo-refractory compounds, planting but not at random, nor by choosing the types of tree among those least expensive to care for, but rather by selecting them among the most suitable species for the purpose.
On this front, the Colombian city of Medellín seems to have set the examplewhere almost ten million dollars have been invested to create green corridors connected to each other, with the aim of offering fresh spaces to pedestrians. They call it the “green wall”; they created it in 2023 and it is made up of 2.5 million plants and almost 880,000 trees planted along thirty urban routes interconnected to each other to counteract the urban heat island effect.
Some models used abroad to combat the summer heat
Other cases studied by Usgs (the scientific agency of the United States government that deals with geology, hydrology, geography and ecology) concern Sydney and Dubaimetropolises that overheat because they are located near deserts. In these contexts, reflective surfaces are effective, as they repel solar radiation, thus lowering temperatures and reducing the column of hot air that is created above cities. TO Singaporewhere according to the local Meteorological Service, the island is warming at double the rate of the rest of the world, +0.25 °C per decade, today the temperature is almost a degree higher than in the 1950s.
Well, the strategy is seeing the application of both architectural and technological innovations in terms of cooling, investing not only in green and shaded spaces, but also in the design of special pipelines for underground cooling. The attempts have used a variety of materials, from reflective paint to lighter-colored asphalt alternatives.
Reflective pavements were laid in Los Angeles and, during a 2022 heat wave, recorded ambient air temperatures as much as 1.67°C lower than those in neighboring areas, at least according to a 2024 study published in ER-Communications at this link: Micrometeorological effects and thermal-environmental benefits of cool pavements: findings from a detailed observational field study in Pacoima, California – IOPscience.
The environmentalist short circuit
A possible solution also in Italy? It is difficult to say, while it is certain that each city must act differently from all the others due to its own environmental and climatic characteristics. Finally, we mention Santiago de Chile, the capital which has committed to planting 30,000 new trees in its metropolitan area. Then discovering that in some cases the plants chosen trapped the heat in the foliage instead of attenuating it. And this is why believing in the demagogy of national cassandras is useless: It’s not by buying an electric car that the problem is solvedIf anything, and this is the case of numerous buildings, there has been the conversion of buildings created for industrial or tertiary use into homes, operations which in many cases took place without knowing that the technical characteristics are certainly not those of a house. And which without air conditioning quickly become ovens.
