Designing Cities Like Ecosystems: Towards a Local Urban Ecology

As cities face intensifying heatwaves, water scarcity or extreme rainfalls, the future of urban climate resilience lies not in imposing high-tech universal solutions but in learning to work with the local ecosystems within urban geographies. 

What if cities learned to work more like the ecosystems they have replaced? Rather than imposing high-tech universal solutions, we can begin with what already exists within a landscape: forests provide shade and stabilise soils, vegetation filters air and wetlands hold excess water. Even no- and low-tech solutions cannot be universal, however. A vertical garden might flourish in a temperate climate, but in a heatwave-prone city such as Madrid, it is a solution that does not understand the local natural ecology.

Medellín, Colombia’s second-largest city, offers an example of how green corridors can alter the temperature and liveability of a city. In 2016, the city began transforming roads and waterways into an interconnected network of green spaces in a response to urban heat and air pollution. Instead of concentrating vegetation within isolated parks, the project created a network of green spaces, where vegetation became part of the infrastructure of the city.  Trees planted through the project were able to reduce surface temperature by 1.5°C, while their shade lowered the thermal discomfort between 2°C – 8°C. Species such as the mango tree (Mangifera indica), already found in Medellín, were specifically planted for their ability to absorb PM2.5 particles. Following the project, local air temperatures fell by around 3°C, alongside benefits of increased urban biodiversity and shaded public space. In 2019, the project received the Ashden Award for Cooling by Nature. The city began to function a little more like a forest, using vegetation as infrastructure, not as decoration.

The relationship between vegetation and resilience is even clearer in Freetown in Sierra Leone. In 2017, the city experienced catastrophic mudslide and flooding, events linked to the loss of vegetation and trees as the city rapidly grew. Trees provide more than just shade: their roots stabilise soil and have the ability to absorb and slow water flow. In response, the local city council launched Freetown the Treetown, a community-led initiative focused on restoring ecological infrastructure through tree and mangrove planting. The project extends beyond planting trees, as local residents are paid to plant and care for them, while their survival and growth is digitally monitored. Restoration goes beyond environmental repair, incorporating employment and community participation into climate adaptation; people become part of the infrastructure too.

If a city can behave like a forest, perhaps it can also behave like a sponge. This is the question being explored by the International Climate Initiative with George Municipality in South Africa, a region that experiences both flash flooding and water shortages. The conventional urban response to heavy rainfall is to remove water as quickly as possible, using roads, drains and pipes to carry it away. But a “Sponge City” works differently – it slows water down, absorbs it, stores it and allows it to be used again, mimicking the functions of a sponge. By considering how a city can become a sponge, we alter the role of infrastructure, changing the purpose from controlling water to creating conditions for water to move through the city more naturally. 

Permeable surfaces allow water to enter the ground, wetlands retain excess water and bioswales collect and filter runoff, which help replicate natural water systems. Excess water is changed to be seen as a resource that can be stored and reused. What connects these three cities is how they are shifting towards mimicking natural ecosystems and organisms, such as forests and sponges, to regulate heat, manage water and support biodiversity. As they demonstrate, a resilient city is not the most technologically advanced, but one that understands its ecological specificity and designs and plans with this in mind.

Words by Anna Borrie for Rethinking Climate 

Rethinking Climate:

In a world often defined by crisis headlines and carbon counts, stories of climate action can feel like they live on the periphery, minuscule in the shadow of an overwhelming challenge. Climate stories go beyond scientists, policymakers, and activists. They also take shape in unexpected places: studios, workshops, design labs, community spaces, small corners of cities and in rural landscapes.

These essays grew out of noticing this. They trace how creativity and care intersect with the climate crisis, how artists, architects, and makers are turning what once symbolised environmental failure into forms of renewal. Each story begins with a familiar problem – a tyre fire on the city’s edge, smog above the skyline, discarded textiles, and industrial offcuts – and follows the people transforming these materials and ideas into new forms of value.

To rethink climate is to shift perspective, to see potential where others see residue, and to design systems that regenerate rather than extract. This isn’t only about technology; it’s about creativity, empathy, and design. It’s about finding beauty in what was once waste and building futures that don’t just sustain life but also enrich it.

Anna Borrie: 

Anna Borrie is Associate Editor at Planted Journal, where she explores the intersections between ecology, art, and storytelling. Her work is rooted in a  creating meaningful connections between people and their environments. She runs a community garden in Madrid, where she cultivates both plants and relationships with fellow gardeners. Her interests lie in creating collaborative environmental art and promoting zero-waste practices, seeking ways to harmonise creativity with environmental responsibility.