As our cities grow denser, the challenge of balancing urban development with ecological sustainability becomes increasingly urgent. Traditional grey infrastructure – roads, roundabouts, and paved spaces – usually takes up the vast majority of our public space. But fail to serve the evolving social and environmental needs of urban communities. 

Yet, despite mounting evidence that these spaces can be repurposed for the benefit of people and the planet, many cities continue to resist change.

We must rethink our urban landscapes. Instead of allowing vast swathes of our cities to remain dedicated to cars and concrete, we should be asking: How can this space serve the broader public good? 

By transforming grey infrastructure into vibrant green ‘socialstructures’, cities can promote biodiversity, enhance climate resilience, and foster stronger community connections. This is not just an aesthetic improvement – it is a necessity for livability, economic growth, and climate adaptation.

In the following, I will try to show how three exemplary projects by the Danish nature-based design studio SLA – Sønder Boulevard in Copenhagen, Gata Grønland in Oslo, and Sankt Kjelds Square in Copenhagen – have reimagined our urban landscapes leading to profound environmental and social benefits. 

These projects not only have reclaimed space for nature but also served as catalysts for economic activity, social cohesion, and climate adaptation, showcasing a transformative approach to urban design that all cities could – and indeed should – follow.

Sønder Boulevard, Copenhagen: A Green Artery for Community Life

In 2006, Sønder Boulevard in Copenhagen underwent a radical transformation. Originally a 1.3 km fenced-off road functioning as a busy traffic corridor, SLA was hired to reimagine the road into a vibrant, green public space that could serve as an ‘outdoor living room’ for the neighborhood.

By optimizing traffic flow and reallocating space, the project reclaimed urban land for both people and nature, which could be used to expand the central green divider into a proper 1.3 km public space that could be filled with a host of active, social, and community-based programs and activities.

The result is a thriving green artery that seamlessly integrates various social spaces, including playgrounds, picnic spots, sports courts, and sun decks. 

From being a rather shady backside of Copenhagen, Sønder Boulevard has evolved into a lively hub, fostering a rich local economy with small shops, artisans, and cafes. Beyond its economic impact, the project has significantly improved urban livability, promoting health and social connection – standing as a model for how cities can repurpose grey infrastructure into multifunctional, nature-infused spaces that enrich everyday life.

Gata Grønland, Oslo: Tactical Urbanism and Public Life Experiments

SLA’s transformation of Gata Grønland in Oslo highlights the power of tactical urbanism and public life experiments in reshaping grey infrastructure. 

In the summer of 2022, a 7,000 m² temporary intervention introduced trees, flowers, and informal gathering spaces along one of Oslo’s central roads. This experiment aimed to explore how a pedestrian-first, nature-based approach could revitalize the challenged Oslo neighborhood of Grønland.

By integrating outdoor seating and retail opportunities into the green design, the project supported local businesses. The results were immediate – foot traffic surged, and establishments such as the legendary Punjab Tandoori, Oslo’s oldest Indian restaurant, even had to hire additional staff to meet demand. 

Due to overwhelming community support, the project was reintroduced the following year, and in 2024 the City of Oslo decided to make it a permanent installation for the next five years.

What makes Gata Grønland remarkable is not just the transformation itself, but the process behind it. This was a city listening to its residents, testing ideas in real-time, and making changes based on real-world outcomes. 

Other cities should take note – when you engage communities in shaping their environment, the results are powerful and lasting.

Sankt Kjelds Square, Copenhagen: A Climate-Resilient Urban Forest

The conversion of Sankt Kjelds Square into Copenhagen’s greenest climate adaptation project showcases how green infrastructure can address both environmental and social challenges.

Previously a traffic-dominated roundabout, Sankt Kjelds Square has been transformed into a lush urban climate forest, integrating stormwater management, biodiversity enhancement, and social infrastructure.

Key elements of the project include the removal of two-thirds of the area’s asphalt (from 15,000 m2 asphalt to 5,000 m2), the prioritization of active mobility, and the creation of a series of lush ‘sponge areas’ to absorb excess rainwater.

A remarkable 586 new trees were planted, contributing to a 1,200% increase in tree cover and a 121% rise in green space. The area’s vegetation now absorbs 3,960 kg of carbon dioxide annually – an increase of 518% compared to the area before – while mitigating the Urban Heat Island effects by more than 8 degrees Celsius on hot summer’s days.

Beyond its environmental benefits, the transformation of Sankt Kjelds Square has also significantly improved urban life. The neighborhood has experienced a 320% increase in public activity, fostering new businesses, cafes, and social interactions. 

Sankt Kjelds Square proves that climate adaptation is not a burden – but an opportunity. Cities that take climate change seriously can not only protect their residents from extreme weather but can also create greener, healthier, and more socially vibrant places in the process.

The Future of Green Socialstructure

The three projects underscore a crucial paradigm shift: urban spaces should prioritize people and nature over cars and concrete. 

Yet, despite the overwhelming evidence that these transformations work, many cities hesitate to follow suit. The fear of disrupting car traffic or the reluctance to challenge the status quo often stifles progress.

But the facts are clear. Converting grey infrastructure into green socialstructure leads to more inclusive, adaptable, and environmentally resilient public spaces that serve both ecological and social functions. The benefits extend beyond aesthetics – these transformations drive economic growth, improve public health, and mitigate the effects of climate change.

So, the real question is not whether cities can do this. The question is: Why aren’t they?

As urbanization continues, it is imperative that city planners and policymakers move beyond hesitation and act decisively. Investing in nature-based solutions and participatory urbanism is not just an option – it is the path to a more sustainable, livable future.

The cities of tomorrow should not be dominated by roads, noise, and pollution. Instead, they should be places where nature, community, and climate resilience converge to shape a better urban condition – for all life.