Are cities getting hotter and hotter? Living in a cool climate could become a privilege reserved for the few

Heat never affects a city uniformly. It lands on asphalt, bounces off facades, gets trapped between narrow streets, and builds up in neighborhoods with few trees and too many mineral surfaces. Two people can live in the same city and experience two completely different climates: one walking under a tree-lined boulevard, the other on a sidewalk with no shade; one inside a well-insulated and ventilated home, the other in a small exposed apartment with no greenery around. Urban temperature is not just a meteorological figure. It is also a matter of design.

Heatwaves are turning urban areas into one of the most tangible frontiers of the climate crisis. According to the 2025 chapter of the European Commission’s climate resilience report, extreme heat is responsible for around 95% of climate-related deaths in Europe, while heat-related mortality has increased by around 30% over the past twenty years, disproportionately affecting people living in dense urban environments because of the urban heat island effect. The reasons are easy to understand: concrete, asphalt, dark roofs, traffic, air conditioning, a lack of vegetation, and soil sealing turn entire neighborhoods into surfaces that absorb heat during the day and release it at night.

Why cities are getting hotter and hotter

In 2025, the issue became even more visible. A report by the World Meteorological Organization and Copernicus Climate Change Service found that 2025 was a year of abnormally high temperatures for 95% of Europe, marked by climate records, heatwaves, and wildfires on a continental scale. But the most important insight, for anyone thinking about cities, is that heat is never only “outside.” It enters the urban form itself. It depends on materials, street orientation, the presence of trees, shade, ventilation, the distance from parks and waterways, and the possibility of finding shelter without having to spend money.

This is why urban design can no longer treat shade as a side effect. Shade is infrastructure. A tree is not street furniture, it is public cooling. Light-colored pavement is not only an aesthetic choice, it is passive technology. A fountain, a portico, a bus shelter, a school open during summer, an air-conditioned library, a park within walking distance are all pieces of climate adaptation. A city that until a few years ago mainly designed around flows, consumption, attractiveness, and image must now design for everyday survival.

Urban heat is also a social issue

The problem is that these solutions are not distributed equally. The climate crisis does not only create new temperatures, it also makes old inequalities more visible. In 2026, the European Commission’s Joint Research Centre published a study covering 862 European cities, showing insufficient access to green spaces and a clear socioeconomic divide: income, density, climate, and the distribution of greenery directly influence the possibility of living in cooler and healthier urban environments. In other words, extreme heat is also a matter of class, age, health, work, and address.

Those who can afford it respond to heat through private solutions: air conditioning, second homes, remote work, home insulation, taxis, gyms, swimming pools, air-conditioned offices. Those who cannot are left in the harshest public spaces: bus stops without shelters, poorly insulated homes, outdoor jobs, crowded public transport, neighborhoods without trees, apartments that do not cool down even at night. This is where heat becomes political. Not because the sun chooses who to hit, but because the city was already designed unequally before the heatwave arrived.

Milan and the urban heat island effect

Milan is a useful example because it makes the issue easy to grasp without abstraction. According to the 2025 report “Che caldo che fa!”, Milan’s urban heat island effect is particularly severe, with a 4.2°C difference between the most urbanized areas and the greenest ones. During the summer of 2024, the city reached the highest risk level for heatwaves for six days, recording three separate heatwaves and an excess mortality rate among people over 65 during the month of August. This does not make Milan an exception, but rather the opposite: it is one of the clearest images of what many European cities are becoming.

The answer cannot simply be to plant trees everywhere, even though trees remain one of the most effective infrastructures. More complex strategies are needed: permeable soils, reflective materials, less asphalt, green roofs, shaded bus stops, depaved school courtyards, ventilation corridors, thermal risk maps, accessible cooling shelters, and maintenance of existing greenery. The 2025 Urban Extreme Heat Risk Management Resource Package by UNDRR, ICLEI, and Making Cities Resilient 2030 specifically insists on the need to treat urban heat as a systemic risk, to be managed through planning, data, governance, and the protection of vulnerable populations.

Cooler cities risk becoming cities for the wealthy

The real question, however, remains: who pays for this transition? Because climate adaptation itself can become unequal. A greener neighborhood may become more livable, but also more desirable and therefore more expensive. A depaved street may improve public health while also increasing real estate appeal. A city that cools itself down without housing policies risks creating a new form of exclusion: no longer just being pushed out of the beautiful city, but also out of the cool one.

This is where urban design needs to change its posture. It is not enough to design greener, more shaded, more resilient cities. We need to design cooler cities that remain accessible. Because in the age of extreme heat, shade will no longer be a comfort. It will become a form of welfare: a city that distributes shade poorly is already deciding who gets to breathe more easily and who must walk through the furnace.