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  • News article
  • 2 June 2025

Renewing urban design in times of heat: Refreshing our cities for resilient spaces

Extreme heat often strains and overheats urban spaces and infrastructure, disrupting city activity. To ensure our cities and towns are not only liveable but also dynamic in a warmer climate, it's essential to redesign our urban spaces to #Refresh.

worms
Extreme Heat
Building Renovation
Urban Design
Urban Regeneration
Adaptation

The tragic floods in Valencia in October last year served as a stark reminder that our built environment is ill equipped to face the extreme weather events that are becoming ever more frequent with climate change. In the same way our buildings, streets and public spaces are not prepared to absorb excessive water in case of flash floods, they are also unfit to bear the burden of scorching heat.

Although the damage of a heat waves is not as strikingly visible as a floods’, extreme heat is the number one cause of climate-related deaths in Europe today. Heat’s negative impact on peoples’ health and wellbeing is only amplified by the way our cities and towns are currently designed in Europe, with high rates of artificial land cover.  

When temperatures rise, many places in our cities – due to overexposure and lack of greenery – trap heat and become unbearable and dangerous, especially for vulnerable populations. This phenomenon is known as the Urban Heat Island effect – where dense, urbanised areas heavily covered in concrete have air temperatures up to 10 to 15 degrees warmer than in fresher, surrounding areas.

Extreme heat’s intensified impact on cities paralyses the dynamic activity and communities that are the heart of city life. Streets are deserted, public transportation grinds to a halt, and outdoor community spaces become vacant and silent.

To keep our cities not only safe but also lively, hitting #Refresh to redesign our cities is crucial – for more heat-resilient infrastructure, spaces and buildings.  

The diagnosis: mapping urban heat islands

Understanding how urban design magnifies heat begins with a clear diagnosis. Mapping Urban Heat Islands offers essential visibility into the areas that overheat most severely, pinpointing zones that become most dangerous during heat waves.  

Heat maps serve multiple purposes: they alert local stakeholders, including municipal leaders, to the scale and urgency of the issue, and they offer a practical guide for intervention. They inform the planning of new developments, the redesign of public spaces, and the retrofitting of existing infrastructure to better suit a warming climate.

Maribor heat map

© Slovenian Surveying and Mapping Authority.

In France, the national Energy and Climate Agency (ADEME) has developed a digital tool called Plus Fraîche Ma Ville (“Fresher My City”) to support cities in diagnosing and addressing urban overheating. It helps municipalities begin with a solid understanding of where heat is most concentrated and what solutions are best suited to those areas.

Toulouse Métropole was the first local government in France to set up a climate observatory, by deploying a network of weather station networks to measure the urban heat islands across the city back in 2014. This was done in the framework of the MapUCE project, where a group of researchers, urban planners and local authorities set up Climate Atlas based on digital simulations before deploying weather stations.

The project developed a reproducible method applicable to all French cities and generated open-access data on the Urban Heat Island effect for around 40 cities across the country.

Heat-resilient buildings

One of the first areas in critical need for redesign to fit for rising temperatures heat are our buildings. As Europeans spend on average 80 to 90% of their time indoors, poorly designed and insulated buildings represent one of the biggest dangers when temperatures get extreme.  

Nearly 75% of homes in Europe were built before modern thermal standards, making them susceptible to extreme heat. Buildings with low ceilings, lacking natural ventilation, that don’t have shutters or blinds, and that are poorly insulated can become deadly when a heat wave hits.  

Despite the growing need to address overheating in buildings, some town planning regulations still prevent effective heat-mitigation measures such as installing shutters, blinds, or reflective paints. Even well-insulated buildings can become uncomfortably hot if solar gains and ventilation are not properly managed. Unfortunately, most energy performance certificates – required in many property transactions and before renovations – tend to overlook summer comfort.

Only a few European countries - Cyprus, Finland, Latvia, Portugal and Spain - have explicitly addressed the issue of summer indoor temperatures in their long-term renovation strategies and cooling issues as part of thermal building regulation considerations. With or without the framework, some cities are stepping up.

Getafe building renovation

© EMSV Getafe (Getafe City Council)

The city of Getafe, part of Madrid metropolitan area, through its extensive Getafe Rehabilita project, has identified priority neighbourhoods and areas where building renovation needs are most pressing. Key actions include façade insulation, passive cooling techniques, and the integration of green infrastructure, aiming to reduce heat accumulation in urban spaces and enhance residents' thermal comfort.

Heat-resilient public spaces

When stepping out of an overheated building, it’s crucial for public spaces to be welcoming and safe for people during a heat wave. Unfortunately, most heat maps will point to the same trend: essential public spaces such as city squares and streets – heavily paved and asphalted – are amongst the hottest spots in cities.  

This not only reduces the number of public spaces where people can cool down outside their homes but also disrupts community life by limiting opportunities for social interaction, further isolating vulnerable people.

In Seville in the South of Spain, the Cartuja Qanat project is reimagining streets as climate-resilient public spaces by combining subtle urban transformation with longstanding cooling techniques. Reviving traditional craftsmanship and cultural knowledge, the project revives centuries-old microclimatic techniques like shaded walkways, open plazas, and comfortable transition zones, that ease movement and offer refuge during extreme heat. Such interventions invite people to linger, connect, and reclaim public spaces no matter the temperature, retaining the city's social and cultural vibrancy.

Bioclimatic design in Seville of CartujaQanat Project

Photos: CartujaQanat

The small city of Rethymno in Crete has also focused on bioclimatic design to enhance resilience in the face of extreme heat. Rethymno piloted bioclimatic design by incorporating the use of compressed soils, cool pavers and photo-catalytic road paint around one of the town's main squares.

As part of the re-design of public spaces for heat, cities are increasingly integrating a nature-based approach. Reggio Emilia in Italy has designed and piloted a new adaptive park model in four city parks with diverse landscapes to mitigate heat islands as well as improving vegetation resilience.

With its Green Radial Strategy, the Portuguese city of Guimarães – next year’s European Green Capital – plans to enhance natural cooling by expanding its green belts, integrating more greenery and water in its urban environment.  

Green Belt Strategy. EGC Application 2026

Green Belt Strategy. Photo: EGC Application 2026

To make greenery the backbone of their urban design, the Spanish city of Viladecans – this year’s European Green Leaf – is following the 3-30-300 rule: ensuring that every resident can view a minimum of three substantial trees from their home; striving for at least 30% canopy cover in all neighbourhoods; and guaranteeing that individuals have access to a green space within 300 metres of their location.

More light-weight urban interventions and repurposing of already existing spaces can also offer relief to people in the midst of an urban heat island. In Lille Métropole, to compensate for the lack of green areas in dense parts of the city, they open vegetated school yards during the summertime to act as public spaces where people can cool down.

Heat-resilient transportation

Another essential part of city life that risks slowing down considerably due to extreme temperatures is the transportation system. Extreme heat impacts our roads and railways by causing cable melting or pavement and track deformities due to heat-induced expansion. This heat stress can lead to structural damages which reduces the lifespan of roads and railways, while demanding more frequent maintenance and repairs.

By the end of the century, the European transport infrastructure will on average experience 30 times more heatwaves – straining the transportation that we rely on every day in and around our cities.

Besides directly impacting the infrastructure on the short and long-term, heat waves also make much of our transport system uncomfortable and for some people, highly dangerous.

Since 2022, Transports Metropolitans de Barcelona (TMB) is piloting a smart ventilation regulation in the metro network to improve environmental quality, hygiene and passenger comfort in stations. The testing sites are conventional lines 1 through 5, which currently transport 95% of all riders.

To combat heat stress for passengers above ground, the city of Vienna tested various green roof solutions for bus stops, evaluating different plant types and shading techniques. They finally rolled out Sedum mat roofs as the most effective solution, known for their easy installation and low maintenance, to reduce ambient temperatures and complement the city’s Green Infrastructure network.

Vienna green bus stops

Photo Source: ClimateAdapt, European Environment Agency

What is your city doing to #Refresh and renew urban design?

Join the #CitiesRefresh Campaign by submitting an action and getting featured on our map here!

To find out more about the urban heat island effect, check out the JRC's Report, "EU Cities and Heat Extremes".

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Fecha de publicación
2 June 2025