28.01.2026

Municipal Strategies for Reducing Urban Heat-Related Mortality

Building design

How cities can save lives with planning and climate design

Everyone is talking about hot cities, but hardly anyone is tackling the root of the problem: heat-related deaths have long been one of the most pressing urban health crises—and they are hitting communities across Germany, Austria, and Switzerland with full force. But how can we sustainably reduce the number of heat-related deaths through strategic urban planning, innovative open-space concepts, and bold governance approaches? Those who focus solely on counting shaded areas are missing the bigger picture. What’s needed are systemic, resilient, and—above all—actionable strategies to combat urban heat-related deaths—from the microclimate to the master plan.

Definition and Causes of Urban Heat Mortality—Why Cities Are Particularly Affected
Analysis of risk factors: vulnerable population groups, social dimensions, and urban climate characteristics
Municipal policy tools ranging from heat action plans to land-use planning and public health protection
Innovative solutions: green infrastructure, blue networks, climate-responsive surfaces, and digital tools
Practical examples from Germany, Austria, and Switzerland—what works, and what remains mere symbolic politics?
Governance, communication, and participation as key factors in sustainable heat strategies
Interactions with other challenges: climate adaptation, social justice, and resource conservation
Methodological Recommendations for Planners and Administrations—From Risk Analysis to Monitoring
A Critical Outlook: Heat-Related Mortality as a Seismograph for the Future of Urban Planning

Urban Heat Mortality: The Underestimated Risk in the Shadow of the Climate Crisis

When people think of climate risks, they often picture floods, storms, or droughts. Yet it is precisely the invisible killer—extreme heat—that now claims more lives in cities across the DACH region than many a storm. Heat-related mortality describes the increase in deaths that are directly or indirectly attributable to high temperatures. And the numbers speak for themselves: While heat waves used to be considered the exception, they are now a regular feature of the warm season—and the trend is on the rise. The problem is particularly acute in densely populated urban areas, where concrete jungles and impervious surfaces further heat up the climate.

The causes are complex. Cities act like gigantic heat reservoirs. Asphalt, bricks, and building facades absorb solar energy and release it only slowly at night. The result: the so-called urban heat island. While the surrounding areas cool down after sunset, it remains warm in the cities—often with fatal consequences for people’s health. In addition, air pollutants, poor ventilation, and a lack of green spaces further exacerbate the strain on the population. When thinking about heat-related deaths, one should not focus solely on older adults with pre-existing conditions. Children, people with chronic illnesses, the socially disadvantaged, and people without a fixed residence are also particularly at risk.

The statistics from recent years are alarming. According to the Robert Koch Institute, several thousand people in Germany died from the effects of extreme heat in the summer of 2022 alone. A similar picture emerges in Vienna, Zurich, and Basel—and the trend is clearly on the rise. Experts agree: heat-related mortality is not just a medical problem, but above all a structural and planning issue. Those who continue to rely on wishful thinking in urban planning risk preventable deaths.

The problem of heat-related mortality is not evenly distributed. Neighborhoods with little green space, high building density, and low socioeconomic status are disproportionately affected. This shows that heat protection is also a matter of social justice. Those who cannot afford their own garden, air conditioning, or flexible work hours are significantly more at risk. Municipal strategies must therefore not only improve the microclimate but also specifically protect vulnerable groups—a balancing act between technical innovation and social responsibility.

Conclusion: Reducing urban heat-related mortality is one of the greatest challenges of the coming decades. We need interdisciplinary approaches that integrate urban climatology, the social sciences, public health, and urban planning—and we need them now. Failure to act now will not only result in preventable deaths but will also undermine confidence in the ability of policymakers and planners to take effective action.

Municipal Policy Tools: From Heat Action Plans to Land-Use Planning

Cities in Germany, Austria, and Switzerland have an impressive arsenal of policy tools at their disposal—at least on paper. The challenge lies in coordinating their use. A key tool for reducing heat-related mortality is the municipal heat action plan. This plan defines coordinated measures to protect the population during extreme heat waves. It ranges from early warning systems and targeted information campaigns to the organization of air-conditioned cooling centers and medical emergency plans. But a heat action plan alone does not make for a cool city. What matters most is how it is integrated with other tools such as urban land-use planning, open-space development, and disaster preparedness.

Urban land-use planning offers enormous potential that has often gone untapped so far. This is where decisions are made about how much green space will be preserved or created in a neighborhood, how dense the development will be, and whether fresh-air corridors will be maintained. Progressive cities are already integrating climate risk maps into their land-use plans. They lower building density limits in areas particularly exposed to heat or mandate minimum percentages of green facades and roofs. However, such requirements need consistent enforcement—and the political will to stand firm even in the face of short-term investor interests.

Health protection also plays a central role. Many public health departments now work closely with urban planners to close existing gaps in heat protection. This ranges from equipping public buildings with heat protection measures to specifically addressing groups at particularly high risk. Mobile advisory teams, checklists for nursing homes, and emergency plans for daycare centers are just as much a part of modern heat strategies as collaboration with neighborhood assistance programs and social initiatives.

Communication and governance are perhaps the most underestimated levers. It is not enough to simply plan measures—they must also be communicated clearly and accepted by the public. Here, some cities rely on digital platforms that provide a centralized source of current heat warnings, cool places to go, and health information. Others are investing in participatory formats that allow citizens to share their experiences and ideas. After all, one thing is clear: if you don’t get people on board, you ultimately risk undermining the effectiveness of even the best strategies.

Ultimately, management is not an end in itself. Municipal heat strategies must be continuously evaluated and adapted. Regular monitoring—such as through the analysis of emergency medical service data, heat indicators, and feedback from neighborhoods—is essential for identifying blind spots and fine-tuning measures. In short: Anyone who wants to effectively combat heat-related deaths needs staying power, a clear compass, and the willingness to make even uncomfortable decisions.

Innovative Solutions: Green Infrastructure, Blue Networks, and Digital Tools

The classic response to urban heat is: more trees, more parks, more water. But it’s no longer that simple. Today, what’s needed are interconnected, multifunctional, and scalable solutions that systematically improve the urban climate. Green infrastructure is far more than just decoration. It includes parks, urban forests, green roofs, and green facades, as well as street trees, pocket parks, community gardens, and wildflower meadows. The strategic placement and interconnection of these elements are crucial for promoting fresh air flow, providing shade, and maximizing evaporative cooling.

Blue infrastructure—that is, water bodies, streams, ponds, fountains, and innovative stormwater management systems—is playing an increasingly important role. It not only provides temporary cooling but also contributes to biodiversity, improves air quality, and enhances the quality of life. Particularly exciting are projects in which rainwater is channeled through the neighborhood via open gutters instead of being diverted into the sewer system. Such measures help increase evaporative cooling and close the water cycle.

Climate-active surfaces are the third piece of the puzzle. Asphalt, concrete, and STEIN store heat particularly efficiently. Innovative materials such as light-colored, reflective pavers, permeable pavements, and cooling coatings offer new possibilities here. Some cities are experimenting with so-called “cool pavements,” which, thanks to special surface properties, remain up to ten degrees cooler than conventional asphalt. Combined with green spaces, these can create genuine local microclimate oases—a benefit for both people and the environment.

Digital tools are the game-changer in today’s urban planning. They make it possible to monitor heat risks in real time, run simulations for new neighborhoods, and evaluate the impact of various measures. Urban climate and health data are made accessible to planners and presented in a way that is understandable to the public. Cities such as Vienna, Zurich, and Hamburg are already using digital twins to test scenarios for future heat waves, identify vulnerabilities, and implement targeted measures. The goal: to direct resources to where they are needed most urgently.

All these approaches show that there is no one-size-fits-all solution to urban heat-related mortality. It’s the combination that makes the difference. Successful municipalities rely on a smart mix of green and blue infrastructure, innovative materials, and digital control tools—and continuously adapt these to the needs of the population and local conditions. This isn’t always cheap, but in the long run, it’s the best investment in the health and quality of life of city residents.

Practice and Perspectives: What Works—and Where Does Symbolic Politics End?

In German, Austrian, and Swiss urban planning, theory and practice are often two different things. While some municipalities have already made impressive progress, in other places much of the effort remains piecemeal or amounts to tokenism. In Freiburg, for example, the globally renowned Vauban neighborhood, with its green corridors, cool courtyards, and car-free zones, ensures a measurably better urban climate. The City of Vienna relies on a comprehensive network of cool public spaces, mobile water features, and targeted greening initiatives—supported by digital heat maps and participatory planning processes. Zurich, in turn, stands out for its strategy of consistently keeping fresh-air corridors clear and embedding heat protection measures directly into its building codes.

Yet these flagship projects are not yet the norm. In many cities, heat protection remains a marginal issue—until the next heat wave claims lives and the press raises an outcry. Often, there is a lack of resources, political courage, or simply coordination between the various administrative departments. Symbolic measures such as installing a few drinking fountains or planting a handful of trees generate short-term publicity but offer little long-term relief for the neighborhoods that are truly at risk.

A key problem remains the social dimension. Especially in low-income neighborhoods—where the need for heat protection would be greatest—there is often the least green space, the most impervious surfaces, and the weakest political lobby. This shows that heat-related mortality is not just a matter of climate, but also a matter of participation and social justice. Municipal strategies must therefore be targeted specifically at areas where the risks are highest and resources are scarcest.

A positive trend is the move toward greater participation and transparency. More and more cities are opening up their planning processes, inviting citizens to help shape them, and embracing open data. Digital tools such as heat maps, feedback platforms, and participatory apps make it easier to assess the effectiveness of measures and adjust them accordingly. But here, too, the same principle applies: without a clear governance structure, data-driven approaches risk becoming an end in themselves or a mere fig leaf.

The crucial question remains: How can we take innovative approaches from the niche to the mainstream? The answer is uncomfortable: It takes the courage to prioritize, more resources for implementation, and a government that is willing to allow for mistakes and learn from them. Heat protection must not remain a luxury project for showcase neighborhoods; rather, it must become an integral part of every urban development initiative—especially in light of an aging and increasingly vulnerable urban population.

Governance, Communication, and the Path to a Resilient City

Reducing urban heat-related mortality is not just a matter of technology and design, but above all a matter of governance. Who steers, who decides, who benefits? Successful municipalities rely on clear lines of responsibility, coordinated processes, and close integration between urban planning, public health, social work, and climate research. This is precisely where the wheat is separated from the chaff: While some cities view heat protection as a cross-cutting issue, elsewhere it gets bogged down in a maze of overlapping responsibilities.

Communication is the lifeblood of any successful heat strategy. Those who fail to inform the public in a timely and understandable manner risk dangerous gaps in knowledge and inappropriate behavior during heat waves. Modern cities therefore rely on multilingual information campaigns, targeted outreach to particularly vulnerable groups, and close collaboration with local influencers—from neighborhood assistance groups to sports clubs. Digital channels, warning systems, and apps help disseminate information quickly and precisely.

Participation is more than just a token gesture. It fosters acceptance, promotes innovation, and brings valuable local knowledge into the planning process. Successful municipalities involve citizens, businesses, academia, and civil society early on—for example, through climate workshops, citizens’ councils, or open data platforms. This makes heat protection measures not only more effective but also fairer and more sustainable.

The path to a resilient city lies in consistent monitoring and continuous learning. Those who collect data early on, evaluate measures, and make flexible adjustments can respond better to new challenges. Innovative cities rely on digital twins, AI-based analyses, and open interfaces to pool knowledge and leverage synergies. The key point is this: resilience is not a final state, but an ongoing process—with setbacks, successes, and a constant stream of new questions.

Ultimately, it’s about the big picture. Reducing heat-related mortality is part of a comprehensive climate adaptation strategy that integrates social justice, resource conservation, and quality of life. It requires planners, policymakers, and the public to adopt a new understanding of the city: not as a static entity, but as a learning, adaptive system. This is where the future livability, equity, and resilience of our cities will be determined.

Conclusion: Heat-related mortality as a litmus test for smart urban development

Reducing urban heat-related mortality is far more than a technical challenge—it is a litmus test for the capacity for action and innovative strength of municipalities in the 21st century. Those who view heat as a cross-cutting issue, develop bold strategies, and implement them consistently not only protect lives but also actively shape the city of the future. It is not enough to plant individual trees or issue heat warnings. What is needed are integrated, socially just, and data-driven approaches that combine green, blue, and digital infrastructure and respond to the actual needs of the population.

Practice shows that while there are many good ideas, there are still too few bold implementations. Heat protection must move out of the niche and into the very DNA of urban planning—from vision and governance to day-to-day communication. Those who invest now will not only save on healthcare costs later but will also gain trust and improve quality of life. And perhaps—just perhaps—the greatest innovation in the end is the courage to question old routines and dare to try something new. The cities of the DACH region stand at a crossroads: They will either become hotspots of resilience—or hotspots of heat-related mortality. The choice is ours.

06.09.2025

Industry news

De Wit: Vapors that defy time

Building design

The De Wit tapestry manufactory in Mechelen, Belgium, is world-famous. Here, antique tapestries from all over the world are cleaned and restored with the utmost care. © De Wit

Light, dust and insects are their enemies: antique tapestries are restored at the Royal Tapestry Manufactory De Wit in Mechelen thanks to a self-developed and patented cleaning system. […]

Light, dust and insects are their enemies: antique tapestries are restored at the Royal Tapestry Manufactory De Wit in Mechelen thanks to a self-developed and patented cleaning system.

Even in the early Middle Ages, they were mostly used to decorate ecclesiastical buildings. The motifs of the tapestries made in monasteries were religious, but changed in a courtly context when the tapestries were also made for the aristocratic class. During state visits and ceremonial celebrations, the ornate tapestries were hung in interior rooms and on exterior façades. They were also used as room dividers to improve acoustics and insulate castle walls from the cold and draughts. As commissioned works, they were based on the dimensions of the respective rooms; large-format tapestries could even decorate entire sequences of rooms. For a long time, they were reserved for the rich and powerful, as they could take several years to produce. After all, tapestries were easy to transport when rolled up and could be hung anywhere for display purposes.

A contract between the client and the tapestry dealer, which set out the conditions for the workshop, contained information about the function, material and size of the tapestry. The client chose the painter and determined the motifs with him. If silk, gold or silver threads were to be used, this increased the price. First, a small sketch was made on paper. This was then enlarged into a drawing. The workshops then translated the design into a textile image. In the late Middle Ages, the cities of Constance, Basel and Strasbourg were among the most important centers of warp knitting. From Brussels to Tournai, the southern Netherlands, which controlled the wool trade due to its proximity to England, then became the main production area. Incidentally, only tapestries from the Manufacture des Gobelins in Paris are considered “tapestries”.

Today, Mechelen to the north of Brussels preserves the tradition of Flemish tapestry art. The Royal Tapestry Manufactory De Wit is located in the brick building of Tongerlo Abbey dating from 1484. It has been run by the fifth generation of the De Wit family since 1889. The founder, Theophiel De Wit, learned the tricks of the trade as an apprentice at the French company Braquenié in Mechelen. He achieved his first successes by adapting to local taste, which demanded only reproductions or variations of the most famous tapestries of the past. Within a few years of handing over responsibility to his son Gaspard, the number of looms and employees had tripled. Contemporary artists were commissioned with the motifs and, with state support, the company survived the economic crisis of 1929. In the early 1980s, the concept was finally changed due to a lack of demand and the focus shifted to trading, collecting and, above all, the techniques of conserving and restoring historical pieces. At this time, the company also acquired the Tongerlo Abbey in the old town to set up the workshops there.

Thanks to its unique infrastructure, which concentrates all aspects of the treatment of antique tapestries within the same laboratory, the manufactory is now a world leader in the preservation of ageing wool and silk tapestries. It also plays a pioneering role in the development of new techniques. Damage is usually caused by the effects of insects, dust, water and light. Nails and screws also leave their mark. Added to this are improper previous repairs and incorrect storage, for example when the fabrics have been folded instead of rolled.

In the past, it was common practice to wash tapestries in temporary baths made of polyethylene and plastic pipes. Cleaning required large quantities of softened and deionized water as well as sufficient drainage. The tapestry was completely immersed in the bath. Mechanical action in the form of a sponge was also essential. To ensure that the entire surface of the tapestry received the same treatment, it was rolled on a roller in the bath. The repeated rolling and unrolling exposed the fabric to considerable stress. The mechanical action could damage delicate threads. The process was lengthy and drying could take between 12 and 24 hours, allowing potentially volatile dyes to spread.

Pierre Maes, the son of Yvan Maes De Wit, leads a team of 15 restorers and art historians as they move through rooms full of colorful balls of wool. Women in white coats bend over long restoration chairs on which centuries-old tapestries are stretched. They have a handful of spools of fine wool and silk in countless shades: ochre, bronze green, blue and crimson. They were selected to match the colors of the damaged weaving. “Our work consists of stabilizing the fabric with a linen cloth placed on the back, which is sewn with these silk threads. In the case of larger gaps, we try not to rework the tapestry identically, but to integrate these gaps into the composition through minimalist interventions,” says Pierre Maes. “When we restore tapestries, we don’t simply weave gold or silver underneath just to make it look better or appear more valuable. Each piece gives us the broad outline of its composition – and we follow it.”

The manufactory sometimes dyes the silk and cotton threads used itself in its laboratory with hundreds of synthetic pigments in order to preserve the colors of the tapestries and guarantee their quality. Before they can take these steps, however, the pieces must first be cleaned. The aerosol suction cleaning method used here was patented over 30 years ago. The suction method has since established itself throughout the museum world as the benchmark method for cleaning antique fabrics. Washing is a risky step: over the years, the cotton has often frayed and the silk has often been pulverized by the effects of time and light. The scientific approach, in which every step is carefully recorded and documented, has set standards.

The system uses a combination of aerosol spray and vacuum suction. It is equipped with integrated sensors to control the pH value, temperature, water flow and pressure. The system consists of a closed chamber with glass panels. The base is a large 5 x 9 meter suction table. There are 45 aerosol sprays attached to the ceiling, approximately 1.75 meters above the platform. During the cleaning process, the tapestry is held in place by continuous suction. When the aerosol is switched on, the chamber fills with water vapor, which is drawn evenly through the entire tapestry. A low concentration of a non-ionic detergent is introduced into the aerosol system for as long as it is deemed necessary for soil removal. This is replaced by softened and then deionized water during the rinsing process.

The subsequent drying process takes place at 30 degrees. Unstable colors flow into the collecting basin. This procedure, including drying, takes around eight hours and is controlled by a series of computers and chemical tests. Famous pieces such as the “Lady with the Unicorn” from the Musée de Cluny in Paris, “Los Honores and Los Paños de Oro” from the Patrimonio Nacional in Spain or the “Le Dais” tapestry by Charles VII from the Louvre have already undergone the process. Regular customers also include private collectors and important collections, such as Spain’s Patrimonio Nacional, the Kunsthistorisches Museum in Vienna, France’s Mobilier national and the Louvre, the Bavarian National Museum in Munich and the UK’s National Trust. “We are in the fortunate position of being able to carry out the most important and most beautiful restoration commissions that are awarded internationally,” says Pierre Maes. And in his hands and those of his highly focused team, they receive the care that these treasures, which are highly prized at art fairs such as TEFAF in Maastricht or BRAFA in Brussels, deserve.

19.12.2024

Artful interlocking

Building design

Living

“Building on” was the motto for the extension of a semi-detached house in Aachen. With a keen sense for the existing, the Amunt architectural office has created an extension that artfully combines the old with the new.

The small house, which is located in a workers’ housing estate on the northern outskirts of Aachen, was purchased by a family of three in 2010. As the floor space of 70 square meters proved to be too small, it was clear from the outset that an extension was needed. The solution was a two-storey extension that cleverly picks up on the cubature of the existing building and at the same time generates an open, independent structure.

The architectural theme of interlocking is a common thread running through the building. Both the shaping of the volume and the spatial organization follow this principle. While the extension on the first floor is clearly recognizable as a new part of the building thanks to the exposed concrete skeleton, on the upper floor it takes up the roof shape of the existing building and creates a polygonal roof sculpture that links old and new.

The floor plan works in the same way. The additional living and dining room is designed as an open “garden room”. The extensive glazing provides a view of the garden, while the brick façade of the existing building becomes an interior wall. The floor above accommodates four bedrooms, two of which are in the extension. Due to the spatial overlap at the intersection of the roof surfaces, the interior bathroom can be naturally lit via a light well. At the same time, its ceiling serves as a sleeping gallery for the adjoining children’s room. The staircase, which forms a transition zone, is of particular importance. An air space has been added to it, making the wooden beam ceiling of the extension visible on the upper floor, as well as the brick wall of the existing building.

The theme of interlocking is most evident in the façade. The unrendered pumice lightweight concrete brick of the extension merges with the clinker brick of the existing building at the verge. Both parts of the building merge into a single unit, but at the same time can be distinguished from each other by the resulting “seam”.

The architects wanted to take away the “hard newness” of the building and incorporate the character of the estate into their design. Thanks to precise interventions, they succeeded. They have created a homogeneous structure whose history remains legible.

Photos: Filip Dujardin