Climate District

In 2011, just days before Copenhagen experienced its most devastating cloudburst in centuries, Third Nature submitted a proposal for Europan 11. The chosen site was the 100 Ha Skt. Kjelds in Østerbro - a dense, asphalt-heavy neighbourhood with untapped potential for social and ecological renewal. While the competition brief focused on urban regeneration and public life, our response went further: it imagined a city that could adapt to future climate realities while enhancing liveability. We proposed reclaiming underused surfaces to form a new, layered landscape of community spaces, green mobility corridors, and stormwater-responsive topographies.

Only two days after the submission deadline, on July 2, 2011, a sudden cloudburst dropped 150 mm of rain over Copenhagen in just a few hours – a 1.500-year extreme rain event. The city’s infrastructure failed catastrophically, causing over €800 million of damage and more than 90,000 insurance claims. Copenhageners called it the ‘Monster Rain’. The event exposed the vulnerability of the existing urban fabric and forced the city to adopt a bold new climate adaptation agenda. Skt. Kjelds was selected as the very first neighbourhood to implement this vision - and our Europan proposal became the foundation for what would become the Skt. Kjelds Climate District, establishing Third Nature as a practice.

From the outset, our approach was guided by a clear principle: climate challenges can be transformed into urban assets. Instead of burying infrastructure below ground, we proposed that the city adapt visibly and beautifully - through design that serves technical, social, and ecological purposes all at once. By analysing the district’s 100 hectares, we identified that nearly 20% of the public urban space - including over-dimensioned streets, lifeless intersections, and surplus asphalt - could be repurposed for climate adaptation without compromising mobility or access.

The result was a high-performing blue-green urban network: streets regraded to channel cloudburst water safely; plazas redesigned as dual-purpose rain gardens and social spaces; and green corridors connecting local biodiversity zones. Spaces like Tåsinge Plads and Skt. Kjelds Plads, once dominated by cars, became vibrant urban commons that detain and infiltrate stormwater while offering places to meet, rest, or play. Along Bryggervangen Street, we introduced stormwater canals, native plantings, and hundreds of trees - creating a cooling urban forest that doubles as climate infrastructure, as well as optimizing the spacious courtyards to green sanctuaries.

The co-benefits are measurable and lasting. The new vegetation mitigates the urban heat island effect, cooling the district by several degrees in summer. The expanded tree canopy and permeable surfaces boost biodiversity, support pollinators, and reconnect fragmented ecological corridors. Streets now prioritize soft mobility - walking, cycling, and social interaction - creating a safer and more equitable public realm. These interventions didn’t just solve a flooding problem; they sparked a broader urban transformation rooted in sustainability, health, and everyday quality of life.

‍

The Skt. Kjelds Climate District redefined how cities can respond to crisis- not by retreating, but by evolving. Østerbro’s early 20th-century ideals of liveability - walkable streets, human-scale buildings, and shared public space - provided a strong foundation. Rather than replace this, we built upon it, using climate adaptation to reawaken and modernize these values. With targeted investments in resilience, the neighbourhood gained a renewed identity and sense of purpose.

At the heart of this transformation was Third Nature’s green and blue masterplan, which established the spatial and hydrological framework for the entire district. We defined core solutions: cloudburst boulevards enabled by surface optimization, retention plazas, surface-based water systems, and biodiverse mobility corridors. This strategic blueprint guided all subsequent phases. Later stages of implementation were detailed by other consultants working within this integrated approach.

The success of Skt. Kjelds propelled Third Nature into a leading role in climate innovation and sustainable urbanism. Nationally, the project became a model for Denmark’s evolving approach to cloudburst management and nature-based infrastructure. Internationally, the project gained traction through platforms such as C40 Cities and exhibitions by the Danish Architecture Center and many other. Our approach informed pilots in New York City, shaped collaboration with cities across Europe, and continues to influence urban adaptation globally.

The Climate District project cemented our philosophy: major urban challenges - climate risk, biodiversity loss, aging infrastructure - can be reframed as opportunities. More than a technical solution, Skt. Kjelds showed how design-led climate adaptation can reshape not just infrastructure - but how we live together in cities in times of adversity. A shift from form-making to strategic, systems-oriented transformation.