The BiodiverCity project in Malmö demonstrates the benefits of green roofs and other green areas in urban environments. Not only do they promote wellbeing, but they also help increase biodiversity and other important ecosystem services.
When it comes to biodiversity, cities today are like deserts because of the scarcity of green areas where wildlife can live. Cities also become heat traps during heatwaves, making it hard for many species to survive. Another urban problem is the lack of areas where rainwater can seep into the soil and be part of the natural water cycle. Heavy rain can consequently cause major problems in cities, with water having to be led away through other infrastructure systems.
The need for more green areas
Cities therefore need to plan and create more green areas. Not only are they fundamental to people’s wellbeing, they are important in lowering the temperature, reducing the risk of flooding and mitigating noise. And they also help increase biodiversity and other ecosystem services.
Malmö’s BiodiverCity project shows this can be achieved in a number of innovative ways, such as using green roofs, walls and mobile vegetation systems. For instance, green areas can reduce problems caused by heavy rain by absorbing and redirecting water.
The BiodiverCity project
The BiodiverCity project was started in 2012 by the City of Malmö. The aim is to develop products, services and processes to increase biodiversity and make the city greener, healthier and more attractive. The initiative has trialled a number of solutions, from green roofs, walls and facades, to mobile vegetation systems and urban habitats.
Innovations in green roofs
Green roofs increase biodiversity in cities by mimicking the original habitat and supporting local biodiversity. They can also replace the area lost to buildings. By strengthening biodiversity, the area can serve more ecosystem services. Different green roofs provide different benefits and ecosystem services, depending on their composition.
One example from BiodiverCity is the development of biotope roofs, which have a thicker substrate than sedum and therefore provide more ecosystem services. The project has developed a range of green biotope roofs, including one that combines with solar panels.
Up to 50 years more waterproofing
In addition to the environmental benefits, the project has also demonstrated economic and other advantages. The project compared maintenance requirements and costs for homeowners. Green roofs were shown to increase waterproofing by 25–50 years, with the additional benefit of reducing noise. Reduced rainwater runoff and relief of heat in the summer also eases the burden on other infrastructure systems.