Why and How Should We Retrofit Our Cities with Nature-based Solutions
2nd September 2026
How can we bring more nature into our existing cities? And what needs to change if nature-based solutions are to become an established part of the way we design, retrofit and manage urban environments?
These are some of the questions being explored by Project REPAIR researchers in a new literature review examining the evidence around nature-based solutions and their role in creating healthier, more resilient and more sustainable cities.
As urban areas continue to grow, the relationship between cities and nature is becoming increasingly important. Urban development can contribute to habitat loss and fragmentation, but cities can also provide important habitats for plants and animals. The review highlights the need to think of cities as living systems, where the built environment, communities and nature are interconnected.
Why Nature-based Solutions?
Nature-based solutions use natural processes to address societal challenges while supporting both human wellbeing and biodiversity. In cities, these can include interventions such as green roofs and walls, alongside wider approaches to integrating nature into buildings and urban spaces.
The potential benefits extend beyond biodiversity. Nature-based solutions can contribute to climate adaptation and resilience, improve living conditions and help address health and community challenges. For example, green roofs and walls can provide passive cooling, reducing the need for air conditioning and the associated energy use and costs.
However, much of our existing urban environment is already built. If nature-based solutions are to be implemented at the scale required, the review argues that retrofit needs to be part of the solution.
Understanding the Challenges
Retrofitting nature into existing buildings and places is not always straightforward.
The review identifies a number of practical challenges, including limited space, existing underground infrastructure, land ownership, additional costs and shortages in the skills required to deliver nature-based solutions through retrofit.
There are also wider questions about governance, finance and responsibility. Successfully implementing nature-based solutions requires collaboration between different organisations, disciplines and communities, as well as greater understanding of who pays for them, who benefits and who is responsible for their long-term management.
This is particularly important because installing green infrastructure is only the beginning. The review highlights maintenance as essential to ensuring that nature-based solutions continue to deliver benefits over the long term, while identifying continuing gaps in knowledge about maintenance requirements and real-world costs.
Putting People at the Heart of Change
People and communities also have an important role to play.
The evidence highlights the importance of engaging local communities during the design process, helping to build a sense of ownership and encouraging participation. Nature-based solutions also require collaboration across disciplines and provide opportunities for co-creation, bringing different forms of knowledge and experience into decisions about how places are designed, used and managed.
Education and skills are another important part of the picture. The review identifies a growing emphasis on developing the skills required for a net-zero built environment, alongside calls for education and training to place greater emphasis on climate change and nature. In Wales, this sits within wider efforts to develop sustainable career pathways and support the transition to net zero.
From Evidence to Action
The review provides an important evidence base for Project REPAIR as we explore what it takes to retrofit nature into our existing urban environments.
The Biome in Swansea provides an opportunity to examine many of these questions in practice – from the performance and maintenance of nature-based solutions to the experiences of the people who live with them, the skills required to deliver them and the wider policy and practice needed to support change.
By bringing together evidence from research with learning from the Biome and the wider city, REPAIR aims to contribute to a better understanding of not only why we should retrofit our cities with nature, but how we can make it happen.