Seite - 406 - in Biodiversity and Health in the Face of Climate Change

406 mental and social measures. This type of research has direct policy implications. Research is needed on the impact of interventions in a variety of green space set- tings, including low- and middle-income countries. Due to the scarcity of the evi- dence base, research on the effects of urban green space interventions on climate change and biodiversity are required. It is imperative that research is provided in a timely and accessible manner, which has implications for current publication and funding models. It is important to note the significant cost in undertaking this type of research. Researchers, practitioners and policy-makers should work together to devise novel strategies to ensure cost-effective and timely research processes, for example, exploring the use of ‘virtual’ research experiments. Researchers should develop relationships with key stakeholders who are responsible for urban green space provision and maintenance, for example, local authorities and housing asso- ciations, thus enabling opportunities for rigorous evaluations of urban green space interventions. There is a considerable gap in the theoretical basis to guide intervention approaches, and further, the current intervention approaches largely negate the large and conclusive cross-sectional evidence base. Future studies should include a more complete description of their intervention strategies and logic models that describe the assumed causal pathways by which they affect the outcomes in order to better understand the underpinning theoretical mechanisms and improve future interven- tion design. The intervention processes logic model should also be used to inform and design the evaluation approach. 17.4 Conclusions Urban green space cannot be seen in isolation from other local government priori- ties such as transport and housing. It must be framed holistically and viewed as a complex system in which the interplay between physical, economic, social and natural ecosystems affects health, behaviours and communities. The growing diver- sity of our towns and cities is transforming how green space is required and negoti- ated for health, well-being, and social and environmental benefits. Preserving and enhancing existing green spaces, and creating new green spaces, is critical. Significant urban green space investment is made worldwide, and many researchers and policy-makers alike have gradually shown increased support to implement cost- efficient and effective urban green space interventions to improve population-level health, well-being, social and environmental factors. Urban green  space interven- tions can deliver health, social and environmental benefits for all population groups  – and particularly among lower socioeconomic status groups. There are very few  – if any  – other public health interventions that can achieve all of this. Acknowledgements Funding for this work was provided by the WHO Regional Office for Europe, based on a project grant from the German Federal Ministry for the Environment, Nature Conservation, Building and Nuclear Safety. The work draws on discussion at a WHO expert panel meeting in September 2016 on urban green space interventions. R. F. Hunter et al.