In cities experiencing heatwaves, cooling is a form of infrastructure, not a household appliance. Carlo Ratti speaks

“For thirty years, the word ‘adaptation’ has been treated as a white flag, as if preparing for a warmer world meant accepting it. Today we are paying the price for that reluctance.” In the week that the Meloni government’s Ministry of Health has warned of the arrival of the summer’s fourth heatwave, Carlo Ratti, architect and urban planner, discusses with Il Foglio the practical options available to cities and their inhabitants for tackling the challenge of high temperatures. Starting with a key fact: to tackle the problem, all efforts and resources to date have focused on cutting emissions, whilst neglecting any measures that might make city summers less stifling – because such measures were seen as a form of surrender. “Reducing emissions remains the only way to prevent the problem from continuing to grow. But we cannot forget about adaptation, because the heat is no longer a forecast: it is already our reality. This is also why we placed it at the heart of the Venice Biennale,” says Ratti, who curated last year’s exhibition around this very theme.

Before turning the air conditioning up to full blast, we have many other options. First and foremost, we can learn from the environment once again, just as traditional architecture did. Persian wind towers channelled the breeze into homes; Arab cities filtered light through mashrabiyya; Singapore’s shophouses provided pedestrians with kilometres of uninterrupted shade. This was climatic intelligence, accumulated over centuries of trial and error.

The task today is to revive those mechanisms — from deep shade to thermal mass, right through to cross-ventilation — and add what was missing from the vernacular: buildings capable of sensing their own microclimate and adapting in real time.

But our way of life can adapt too. Doing away with the requirement to wear a jacket in the office is equivalent to reducing the need for air-conditioning by a couple of degrees. Taking a break during the hottest part of the day allows us to work more effectively when it cools down again. This practice is still observed today in Spain, but it was also the norm in the Piedmont countryside where I grew up: in summer, we would rise at six, lay down the pruning knife around ten, and resume work in the late afternoon.

The most obvious mistake is having paved over the ground. Black tarmac absorbs heat throughout the day and releases it throughout the night. It also makes our towns and cities impervious to water, increasing the risk of flooding.

This is why there is so much talk these days about ‘sponge cities’: a model that restores the soil’s permeability and makes way for green spaces.

In 1898, Ebenezer Howard envisaged the garden city as a reconciliation between town and country. The twentieth century, however, transformed this idea into the sprawling suburb. We have brought the city into the garden, paving the way as we went. Now we must do the opposite: bring the garden back into the city, especially in the densest neighbourhoods, where heat and people are concentrated.

This is already happening, with urban afforestation schemes, depaving initiatives and urban woodlands. The thermal surveys we presented with the Senseable City Lab at last year’s Biennale, from Amsterdam to Dubai, show that mature trees can lower the temperature of a narrow street by up to five degrees.

The most important innovation is a change of perspective. We need to think of refrigeration as a form of infrastructure, on a par with water or electricity, rather than as a household appliance: a white box bolted to a window.

The small, dripping boxes that still dot the façades of buildings around the world today are descended from a technology invented in the United States in 1902. Today, there are better systems available that can exchange heat with the ground or with water, where temperatures are lower. This results in greater efficiency, whilst at the same time avoiding the release of additional heat into the urban atmosphere.

Furthermore, one of Europe’s strengths – district heating networks – can be repurposed for summer cooling. Integrated with thermal storage systems, these networks enable ‘cooling’ to be produced when energy is abundant and low-cost, for use during periods of peak temperatures. Finally, real-time sensors and artificial intelligence can optimise the balance between energy production and cooling demand in ways that were not possible until recently.

Approaches of this kind could lead to smarter, more efficient and more sustainable cooling infrastructure. They could also generate new industrial opportunities in a sector in which the continent continues to excel, thanks to companies such as Danfoss, Bosch and Schneider Electric. Europe should seize this opportunity to develop a new model for urban cooling, capable of meeting not only its own needs but also the growing demand from the Global South

I would say Paris. It is one of the major European cities that has invested the most in adapting to the heat, with an ambitious urban reforestation programme, a network of climate shelters and one of Europe’s largest district cooling networks, managed by Fraîcheur de Paris. Yet, even this summer, people have died alone in their homes, trapped under the roofs. A sign that we need to step up our efforts even further.

A topic particularly close to my heart is urban afforestation, which remains the most sustainable way to cool cities. In Italy’s historic cities, this requires close dialogue between citizens, local authorities and heritage conservation bodies. But we must start immediately.

I hope for both. Cholera did not merely bring sewers to the nineteenth century. It gave London and Paris their parks, their riverside promenades and, ultimately, their modern form. The fear of foul air and contaminated water gave rise to the most fruitful period in the history of urban planning.

The heat can bring about the same transformation, if we take it as seriously as our great-grandparents took epidemics. Then today’s cities — sealed off, grey, dependent on vehicles that further heat up the streets — will appear to our grandchildren as cities before modern hygiene appear to us today: not evil, simply unaware of something that, over time, has become obvious.