Black asphalt streets that heat up to foot-burning temperatures on hot days are becoming a thing of the past. A revolution in public space design is underway in cities around the world to combat the urban heat island effect. Instead of concrete wastelands, cooling pavements, ventilation corridors and green oases are being created to lower temperatures by several degrees.
Prolonged heatwaves are no longer an exception but are becoming the new normal, transforming the way cities are designed. Over the past two decades, Europe has become the fastest-warming region during the summer months, and the number of days with extreme temperatures is rising year on year. According to forecasts from the Institute of Meteorology and Water Management, the summer of 2026 in Poland is expected to be warmer than average, with heatwaves occurring more frequently and lasting longer. At the same time, experts warn that by 2050, around 163 million Europeans could experience record-high summer temperatures, and the number of heatwave days could quadruple. This means that adapting cities to climate change is no longer a theoretical exercise but an urgent necessity driving new urban projects and the modernisation of existing infrastructure.
In urbanised areas, the problem of extreme heat is amplified by the urban heat island effect. Concrete, asphalt and dense development absorb solar radiation during the day and release it at night, making city centres on average several degrees warmer than the surrounding areas. Densely built urban areas with their concrete roads, impermeable surfaces and limited green space can be as much as 10 to 15 degrees Celsius hotter than nearby rural areas. In practice, this means that a resident of a city centre on a hot day experiences significantly higher temperatures than a resident of the suburbs. Heatwaves are already being called silent killers – when a heatwave swept across Europe in late June 2025, around 2,300 people died in the 12 largest cities, and the latest research indicates that about 65 percent of that number can be attributed to climate change.
In response to these challenges, architects and urban planners around the world are developing new standards for street design aimed not only at moving people and vehicles but also at actively cooling the surroundings. The broad policy of urban adaptation today encompasses a whole range of tools: from passive cooling methods, through the expansion of green and blue infrastructure, to the implementation of Municipal Adaptation Plans. A key approach is multifunctional urban planning that combines cooling objectives with other functions such as water retention, recreation and mobility.
Cooling pavements instead of hot asphalt. A revolution underfoot
Traditional black asphalt, which covers most of the world’s streets, is one of the main culprits of the urban heat island effect. It absorbs 80 to as much as 95 percent of solar radiation, storing enormous amounts of heat and releasing it into the surroundings for many hours after sunset. A solution gaining popularity is so-called cooling pavements, which reflect solar radiation instead of absorbing it. In Los Angeles, where summer temperatures regularly exceed 38 degrees Celsius, the city is testing a special grey paint for coating pavements that, after one application, lowers the surface temperature by about 11 degrees Celsius. This city of 4 million residents became the first in the world to test this technology on public streets, following earlier trials in car parks. This initiative is part of a broader trend in which cities are experimenting with various ways to reduce the heat island effect.
Other solutions go even further. In the Dutch city of Utrecht, on Paardenkerkhofstraat, 800 square metres of paving stones were removed and replaced with grass concrete slabs. Forty-five new trees were also planted and larger green areas were created. A street that was once a hot spot of the heat island has become a cooler and more comfortable place. A similar approach has been used in the Indian city of Ahmedabad, where more than 100 road intersections are being redesigned – hard surfaces are being removed and replaced with vegetation to reduce heat retention in congested transport hubs while simultaneously increasing green areas.
Scientists emphasise, however, that cooling pavements are only one piece of the puzzle. Research shows that they can carry certain environmental costs, which is why testing on a smaller scale before large-scale implementation is so important. George Ban-Weiss, a professor of engineering at the University of Southern California, notes that strategies such as planting trees along streets or using cool materials on roofs are more obvious and proven solutions. Nevertheless, experts point to the equity aspect – cooling pavements provide benefits to all residents regardless of their income, unlike air conditioning, which not everyone can afford. Thanks to them, people who have to be outdoors are better protected, and lower temperatures mean less energy consumption for building cooling.
Greenery is not just decoration. Trees lower temperatures by up to several degrees
Planting trees along streets is one of the oldest and at the same time most effective methods of combating urban heat. The latest research indicates, however, that it is not just about the number of trees but about their appropriate selection and placement. In Melbourne, researchers found that street trees reduced the thermal radiation absorbed by pedestrians by more than 18 degrees Celsius compared with streets without trees. Even if the air temperature changed only slightly, shaded streets were noticeably cooler. The structure of greenery also matters – research has shown that layered vegetation, where trees are combined with shrubs and ground cover, cools cities more effectively than trees alone.
In response to these findings, cities around the world are redesigning their streets to make room for greenery. In London, a climate risk map has been created to help boroughs identify communities most vulnerable to extreme weather events. In new urban areas, canopies and awnings are being installed over shopping streets to provide shade. In Poland, Kraków is conducting public consultations on a programme to green 78 streets, showing that this trend is also reaching the Vistula River. In Paris, where heatwaves are becoming increasingly severe, asphalt school playgrounds are being transformed into green, public cooling zones, providing an example of a successful adaptation project.
Experts emphasise that designing streets with heat in mind is not just about planting trees but also about creating shaded pedestrian corridors and ventilation paths that allow cooler air to flow. A properly designed street can not only lower temperatures but also improve the thermal comfort of pedestrians, which has a direct impact on public health. This is why urban planners increasingly speak of the need for a complete paradigm shift – streets are no longer treated solely as corridors for cars but as spaces that actively improve the quality of life for residents.
Paris cools the city with the Seine
While most cities turn to air conditioning in response to heatwaves, Paris has gone in a completely different direction. The city has for years been developing one of the world’s largest district cooling systems, using water from the Seine to cool buildings. The system consists of 120 kilometres of underground pipes that distribute chilled water to museums, offices, hospitals, schools and public buildings, including the Louvre, the Grand Palais and luxury hotels. Instead of thousands of individual air conditioning units, cooling is produced centrally and provided as a utility service.
The principle of operation is surprisingly simple. Cold river water from the Seine is pumped through one pipeline that runs alongside another carrying warm water from the city’s buildings. A thin metal wall separates them, and a heat exchanger allows heat from the warm urban water to transfer to the cold river water without them mixing. It is like holding hot tea in a bowl of cold water – the liquids do not touch, but the tea cools down. The chilled water is then distributed to buildings connected to the network, and the water from the Seine returns to the river slightly warmer than before.
The plan was formulated as early as the 1990s, and in 2022 the city began a huge, multi-year expansion of the underground infrastructure. By 2042, the network is to be tripled, covering all districts of Paris and reaching more than 3,000 buildings, including key facilities such as hospitals, schools, nurseries and care homes. As energy and climate expert Thibauld Voïta puts it, this is a kind of miracle solution in the era of global warming. The system also aims to discourage Parisians from installing air conditioning, which releases hot air onto the streets, exacerbating the heat island effect. Although the system does not completely solve this problem – it returns warmer water to the Seine – there is no clear evidence so far that it harms the river’s ecology.
Shade saves lives. A new philosophy of public space design
The change in street design is not just about technology but also about a shift in thinking about public space. Kelley Turner, an urban planning expert, argues that in an increasingly hotter world, we must overcome prejudices against shade and darkness during the day. Too many tall buildings can trap heat and raise air temperatures, especially at night – this is the phenomenon known as the urban heat island. Instead, cities should design streets in a way that maximises the use of natural shade and ventilation.
The latest research shows that a difference of just a few metres can mean a temperature difference of nearly 50 degrees Celsius. This is why it is so important to design streets with the people who have to walk on them in mind. In Melbourne, where detailed research on pedestrian thermal comfort was conducted, a range of solutions were proposed, including shaded footpaths, climate-sensitive paving materials and improved air circulation.
In Poland, as in other countries, cities are only beginning to implement these solutions. The key, however, is for climate adaptation plans to cease being documents and become real investments. As experiences from other parts of the world show, effective adaptation requires passive cooling methods such as planting trees and creating shaded public spaces, green roofs and parks, as well as better-designed streets. In the face of the coming heatwaves, which according to forecasts will become more frequent and intense, designing streets with extreme temperatures in mind is no longer a luxury but a necessity.
Fot. Unsplash
