Rooftops, schoolyards, and public squares are types of urban spaces where change can happen. Following a harsh summer of heatwaves, the city of Paris sought ways to increase the accessible green spaces for its citizens to enjoy and shelter during weather extremes. Considering that the schoolyards are open spaces located in the heart of every neighborhood, the city identified the opportunity that laid in their transformation. By unraveling the asphalt of the playground and substituting at least 20-30% of the total surface with vegetation, the city achieved to create an oasis in the heart of the selected neighborhoods, capable to enhance the microclimate and restore biodiversity at the local scale; the so-called OASIS Schoolyards. Moreover, the direct access to the schoolyard from the street, provided the opportunity to open access to the local community after school hours. Therefore, it is expected that the transformed schoolyards are not only more inviting and enjoyable spaces for their everyday users; the children, but they also become the neighborhood’s pocket parks. The multiple co-benefits of these nature-based solutions go beyond the environmental domain to the children’s developmental needs and wellbeing as the OASIS design approach includes natural playgrounds and vegetable gardens.
IGNITION has shown that a diverse range of nature-based solutions such as rain gardens, street trees, green roofs and living walls can be installed in existing urban fabrics. The sustainable urban drainage systems have not required any heavy digging, have been slightly heightened as to not touch existing underground pipeline systems. The living walls and green roof were adapted to be installed on an existing university building. The living walls stand thanks to a lightweight steel frame, adding no weight to the building, while the green roof has been carefully planned to limit the weight of monitoring devices, soil and plants species. The partner went to the extent of showing how trees can be installed on existing roofs by using a light-weight tree pit. All these solutions work in combination and create water system supporting wildlife and biodiversity at no extra cost.
However, public spaces are not the only spaces that cities can consider for transformation. The RESILIO project in Amsterdam moved beyond its public domain and explored the opportunity to utilize private spaces, for the installation of blue-green solutions. The vision of the RESILIO project is to transform the -otherwise empty- rooftops into an innovative system of stormwater management that mitigates the risk of flooding while also tackling important environmental challenges such as the Urban Heat Island phenomenon in the densely built urban fabric. The RESILIO project chose to pilot this system on the rooftops of social housing projects, given that social housing companies are public-private entities and therefore an optimal example to engage the private sector in this innovative concept. The opportunity that emerged with the project is the quadruple-helix collaboration for the implementation and maintenance of the blue-green rooftops as well as the new legislation that is anticipated to lead to further innovation. The RESILIO blue-green solution contributes significantly to the enhancement of the local microclimate and prevents flooding risks while social housing companies benefit from the private use of the collected water. In fact, RESILIO has proven that multi-stakeholder collaboration with mutual benefits is a key element for successfully implementing the city’s climate adaptation strategy.
Ultimately, small-scale interventions that are strategically located within the urban fabric can drive change on the large scale by transforming the urban context and strengthening the city’s resilience to climate change impacts.
 Government, private sector, research institutes and civil society