Green and blue infrastructure (GBI) has the potential to effectively slow down, halt and reverse the negative effects of human activities on the environment while safeguarding valuable ecosystem services that these natural settings provide, especially in urban areas. The successful implementation of GBI is linked to a variety of factors, especially so the policy and institutional framework in which they are embedded. Acknowledging this potential, this report aims to understand the policy contexts which foster or hinder the uptake and positive impacts of green and blue infrastructure across a range of European cities.

The work for this report has been conducted within the context of the Biodiversa-funded ENABLE project, and focuses on the project’s five European case studies (Stockholm, Barcelona, Halle, Lodz and Oslo). For each city, a governance analysis was conducted, focusing on policies, regulations and programmes in place to foster or regulate GBI more generally and regarding specific GBI interventions. Across the cities, a total of 51 instruments relating to GBI were reported and included in the analysis. Subsequently, the (potential) impacts of each city’s policy framework on GBI implementation, maintenance and monitoring are explored as well as the stakeholders and institutions involved in these processes. In a next step, the relevance and effectiveness of the analysed polices as well as barriers in establishing and maintaining GBI are assessed. Our findings offer conclusions on the effectiveness and success factors for GBI implementation, as well as overarching limitations.

The analysis revealed that the most common instrument type within the reviewed GBI-related policies is plans/programmes, followed by guidance documents and strategies and a few laws and regulations. In looking at the level of legal bindingness, the majority of instruments with information provided were found to be non-legally binding (64 %). The most frequently reported mechanisms were regulatory, planning/zoning, and research/monitoring in nature. Within these instruments, the cities illustrated that introducing standards on green space availability and/or accessibility within policy instruments as well as ensuring sufficient funding through targeted programmes and initiatives can be a powerful tool to support GBI implementation.

Of the reviewed policy instruments, almost half are expected to have high impact potential and a third to have medium impact potential. Regulatory and financial mechanisms are amongst those most likely to have a high or medium impacts. To complement this assessment, the policies were also evaluated for their effectiveness, taking into account the extent to which it has addressed GBI and its relevance and how the policy is intended to deliver change. On this basis, circa half of the instruments were evaluated as being of medium or low effectiveness, with only 4 % having been assessed as being highly effective.

Limitations to existing policy instruments were found in all steps of GBI implementation across the case studies. Lack of financial resources can affect early stages of GBI planning as well as continuous support beyond term cycles. In addition, the financial and temporal constraints of political action and a conflicting policy landscape in terms of priorities of different policies affect GBI implementation. Finally, unclear or missing responsibilities for GBI policy and planning limit implementation.

Across all of the case studies, representatives of multiple policy and planning levels were found to be involved in the decision making-processes that govern GBI. Other stakeholders are also involved to varying degrees in different stages of implementation. While public participation is legally mandated in some cities for certain types of government-driven GBI, other cities have limited precedents of bottom-up or inclusive approaches and largely lack stakeholder involvement in planning, implementation, maintenance or monitoring processes.

Overall, the lack of financial resources and allocation of funds to invest in GBI is the major barrier to implementation on a regional and city level, as well as for specific GBI interventions. Furthermore, a lack of institutional capacity, knowledge and expertise, lack of trust between stakeholders, and missing of coordination between government departments as well as the absence of existing policy played a key role in the lack of investments into GBI interventions.

The insights from the five ENABLE cities show that a meaningful implementation of GBI requires a political commitment at the national as well as the city level in correspondence with a long-term vision and must be operationalised by appropriate policy instruments. Tailored guidance, tools to support implementation/decision-making and or action plans to accompany policy instruments can also be used to achieve the aims of specific policies or strategies and operationalise policies. Financial support through targeted programmes and initiatives are also key, fostering a shift from financing purely grey solutions to financing GBI or hybrid (green and grey) solutions and recognition of the benefits of natural capital in financing mechanisms. Finally, GBI should be integrated into existing policy frameworks rather than treating it as an isolated programme and therewith pursued together with other complementary objectives such as climate change mitigation and adaptation, human health and well-being, improving air quality, stimulating the local economy, conserving biodiversity, etc. Together, these actions and approaches can support an increased role of GBI as an integral part of sustainable urban development.