From 30 km/h speed limits to green infrastructure: how the Confederation is redesigning urban spaces to combat heat islands.

Le heat waves The results of last summer have shown that the effects of climate change are already visible, even in the heart of Europe. Swiss cities were among the first to give due credence to the words of climate scientists, and have long been pursuing ambitious mitigation policies, implementing local measures. climate adaptation To protect the population from extreme heat. These include restoring waterways to their natural state, greening neighborhoods, and removing asphalt from as many surfaces as possible. This, however, requires a profound restructuring of our concept of urban mobility.

Climate change in Switzerland: challenges for urban areas

Heat islands, more intense and frequent rainfall, and increasingly less snowy winters: the effects of climate change are now clearly visible even in Swiss cities. This phenomenon affects a large portion of the population, given that nearly three-quarters of Swiss residents live in urban areas.

As he remembers Ana Maria Vicedo-Cabrera, Professor of Climate Impact and Public Health at the University of Bern, “Extreme weather events are altering the global disease profile and exacerbating existing public health threats.”, especially at the expense of vulnerable groups such as the elderly, patients with chronic diseases, people with limited socioeconomic resources, pregnant women and children.

The city is already the elective scenario for testing adaptation strategies to an increasingly warm and unpredictable climate: the urban environment, which cements the earth as much as social inequalities, is considered a tipping point for the exacerbation of the health effects of climate changeBut cities, Professor Vicedo-Cabrera points out, also offer unique opportunities to mitigate these effects:

Climate change preparedness strategies in urban settings are likely to bring additional health benefits. For example, implementing green infrastructure to mitigate the urban heat island effect would also help maintain good mental well-being, stimulate physical activity, and improve cardiovascular health. Similarly, using covered, air-conditioned public spaces during heatwaves (e.g., climate shelters) could improve social cohesion and reduce social isolation, particularly among older people.

And there are already projects that show the potential for success of this approach, such as the plan Optingerstrasse, the “sponge city” of Bern, which unites politicians, scientists and the local population in combating the heat island phenomenon.

Swiss cities prepare for a warmer world

But there are not only experimental interventions of Bern, such as the greening of Schützenmatte or the Stöckacker Süd complex. Adapting to the climate also involves seemingly simple yet fundamental measures, such as the provision of climate-controlled shelters for the elderly, planting trees, and removing as much asphalt as possible.

A BaselFor example, impervious surfaces are being removed in public spaces and vegetation is being planted wherever possible.

"The number of trees in Basel continues to grow. Between 2020 and 2025, we planted a total of 1.147 trees."

says Conradin Cramer, State Councillor of the Canton of Basel-Stadt. In Voltaplatz, for example, approximately 670 square meters of asphalt were removed, 12 new flowerbeds were created, fragile trees were replaced with more resilient specimens, and shaded benches were installed. The city has implemented the "Net Zero 2037" climate protection strategy and 64 adaptation measures, including the development of public transportation and the promotion of energy-efficient renovations of buildings.

Freiburg It is strengthening its heatwave plan for seniors and implementing a Climate Plan structured around 10 key measures, including promoting resilient green spaces, developing urban cool zones, combating urban heat islands, managing water resources based on the "sponge city" concept, protecting natural resources, and monitoring risks. The city is also gradually integrating the Swiss Sustainable Building Standard into its redevelopment projects.

The plan of Lausanne, adopted in 2021, is among the most ambitious: the city aims to achieve climate neutrality by 2030, therefore it includes numerous measures regarding sustainable mobility, as well as heating efficiency improvements and experimental eco-neighborhoods such as Plaines-du-Loup.

Conference of Cities for Mobility: Eliminate the asphalt

That of the city ​​mobility It is not a secondary issue, if we talk about mitigating the effects of climate change: to let cities breathe and discourage the formation of heat islands, it is now clear, we need remove as much asphalt as possibleThat is, we need to take space away from traffic and car life and give it back to nature. As stated in a recent press release from the Union of Swiss Cities, this ambition requires simple but no longer postponable measures, such as the introduction of speed limits of 30 km/h. As he explained Esther Keller, President of the Conference of Cities for Mobility and State Councillor of Basel-Stadt,

"Climate adaptation and transportation policies must go hand in hand. If we want climate-friendly and pleasant cities to live in, we must use road space more efficiently, and the 30 km/h speed limit is a key measure."

The methods to free up space, transport officials point out, Conference of Cities for Mobility, are well known: prioritizing public transport, pedestrian and bicycle traffic, postponing car trips, increasing vehicle occupancy, optimizing parking, and reducing speed. As they explain in the press release,

"On a one-kilometer stretch, reducing the speed limit from 50 km/h to 30 km/h frees up several hundred square meters for greenery. Especially on main roads, a 30 km/h speed limit is therefore a prerequisite for effective climate adaptation, not to mention its positive effects on road safety and noise reduction."

Therefore they ask that the cantonal authorities "stop hindering or even blocking” the implementation of 30 km/h speed limits in Swiss cities, allowing municipalities to independently decide where to apply this speed reduction.

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