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Green roofs provide multiple benefits including reducing the urban heat island effect, absorbing stormwater and air pollution, and serving as habitat for wildlife. However, many cities have not taken advantage of green roofs as a nature-based solution. In New York City (NYC), approximately 20% of the landscape is covered by buildings, thus rooftops present a substantial opportunity for expanding green infrastructure. Spatial data on green roofs are critical for understanding their abundance and distribution, what filters may drive spatial patterns, and who benefits from them. We describe the development of a green roof dataset for NYC based on publicly available data and classification of aerial imagery from 2016. Of the over one million buildings in NYC, we found only 736 with green roofs (<0.1%), although there may have been others we did not detect. These green roofs are not evenly distributed in NYC - they are most common in midtown and downtown Manhattan, while most other areas have few to none. Green roofs tend to be more prevalent in parts of NYC with combined sewer systems, but some such areas, and those with the most heat-vulnerable communities, have few if any despite their potential to help ameliorate stormwater and urban heat challenges. Though green roofs are providing some benefits within NYC, we anticipate they are filtered based on dynamics of infrastructure, institutions, and perceptions, rather than targeted to address climate and weather-related challenges. There is substantial opportunity in NYC to increase green roofs, and equity of them. The dataset we developed is publicly available and can serve as a baseline for tracking these assets through time, while supporting further research, conversations, and policies related to the benefits and distribution of green roofs. The underlying methods can also be applied to help fill similar data gaps in other cities. [ABSTRACT FROM AUTHOR]

The understanding of urban social-ecological systems requires integrated and interdisciplinary methods. This paper explores differences in the accessibility of urban green spaces (UGS) based on urban morphology. In contrast to other comparative analyses that followed simplified quantification of UGS provision and/or omitted the impact of morphological properties of urban space, this study proposes three improvements. First, it uses the share of UGS in the service area of 300 m walking distance around each residential building in a city as a measure of UGS provision. Second, it includes the potential physical accessibility of UGS as warranted by key actors, such as owners or managers, who decide whether UGS are open or not to potential users. Third, it links UGS accessibility and heterogeneous urban structures. We developed a mixed-methods analysis that combines multiple data sources regarding UGS, the spatial distribution of residential buildings, and street networks. We conducted our analysis in five case-study cities (Barcelona, Halle, Lodz, Oslo, and Stockholm). Our findings suggest that the urban structures where the human-environment interaction transformed the space (such as in the core city areas) are characterized by limited UGS in the service area. Urban structures that are less transformed by human activity (especially suburbia) have the highest share of selected UGS in the service area. In addition, even if the share of UGS in the service area is high, many of them might have limited physical accessibility. In the broader sense, this highlights that social-ecological processes are linked to urban form and cannot be separated in an analysis. Therefore, social-ecological systems could be better understood through the lens of urban morphology. [ABSTRACT FROM AUTHOR]

Present and future urbanization together with climate change and other uncertainties make urban quality of life a critical issue, and one that will need constant attention and deliberation. Across cities and contexts, urban ecosystems in the form of green and blue infrastructure, have the potential to contribute to human well-being as well as supporting biodiversity, and to do so under diverse conditions. However, the realization of this potential depends not only on the green and blue infrastructure itself, the well-being benefits are outcomes of the structures and processes of the entire urban system. Drawing on theory and insights from social-ecologicaltechnological systems (SETS) research and resilience assessments, we describe how a systemic understanding of the generation and delivery of green and blue infrastructure benefits may inform cross-sectoral strategies and interventions for building resilience around this particular aspect of human well-being. Connecting SETS to non-academic discourse and practice, we describe the urban system in terms of three systemic controlling variables: infrastructure, institutions, and the perceptions of individual beneficiaries, which we call filters, and how these can be used in different participatory processes to assess and build resilience around green and blue infrastructure and its benefits. To ground the conceptual and theoretical framework in real world complexity and make it operational in practice we discuss three case studies applying the framework in Barcelona, Halle, and Stockholm. All cases share the same general three-step process but their individual combinations of methods and adaptions of the filters framework are designed to fit with three necessarily unique collaborative, transdisciplinary processes. The cases are discussed in terms of outcomes and output, the ways they made use of the conceptual framework, and the challenges they faced. This exploratory work points to a new way of engaging with urban resilience--the strength of the approach is that it is not limited to the identification of specific interventions or policy options, nor trying to prevent change; rather it focuses on how to move with change and build resilience through constant balancing of different types of SETS change. Our study reinforces the growing understanding of how well-being benefits positioned as emergent outcomes of internal SETS interactions offers leverage for mainstreaming green and blue infrastructure throughout diverse governance processes and sectors. [ABSTRACT FROM AUTHOR]

Understanding opportunities as well as constraints for people to benefit from and take care of urban nature is an important step toward more sustainable cities. In order to explore, engage, and enable strategies to improve urban quality of life, we combine a social-ecological-technological systems framework with a flexible methodological approach to urban studies. The framework focuses on context dependencies in the flow and distribution of ecosystem service benefits within cities. The shared conceptual system framework supports a clear positioning of individual cases and integration of multiple methods, while still allowing for flexibility for aligning with local circumstances and ensuring context-relevant knowledge. To illustrate this framework, we draw on insights from a set of exploratory case studies used to develop and test how the framework could guide research design and synthesis across multiple heterogeneous cases. Relying on transdisciplinary multi- and mixed methods research designs, our approach seeks to both enable within-case analyses and support and gradually build a cumulative understanding across cases and city contexts. Finally, we conclude by discussing key questions about green and blue infrastructure and its contributions to urban quality of life that the approach can help address, as well as remaining knowledge gaps both in our understanding of urban systems and of the methodological approaches we use to fill these gaps. [ABSTRACT FROM AUTHOR]

Urban green and blue space interventions may bring about unintended consequences, involving trade-offs between the different land uses, and indeed, between the needs of different urban inhabitants, land users, and owners. Such trade-offs include choices between green/blue and non-green/blue projects, between broader land sparing vs. land sharing patterns, between satisfying the needs of the different inhabitants, but also between different ways of arranging the green and blue spaces. We analyze investment and planning initiatives in six case-study cities related to green and blue infrastructure (GBI) through the lens of a predefined set of questions--an analytical framework based on the assumption that the flows of benefits from GBI to urban inhabitants and other stakeholders are mediated by three filters: infrastructures, institutions, and perceptions. The paper builds on the authors' own knowledge and experience with the analyzed case-study cities and beyond, a literature overview, a review of the relevant city documents, and interviews with key informants. The case studies indicate examples of initiatives that were intended to make GBI benefits available and accessible to urban inhabitants, in recognition of GBI as spaces with diverse functionality. Some case studies provide examples of trade-offs in trying to plan and design a green space for multiple private and public interests in densely built-up areas. The unintended consequences most typically resulted from the underappreciation of the complexity of social-ecological systems and--more specifically--the complexity of the involved infrastructures, institutions, and perceptions. The most important challenges addressed in the paper include trade-offs between the different ways of satisfying the residents' different needs related to the benefits from ecosystem services, ensuring proper recognition of the inhabitants' needs and perceptions, ecogentrification, caveats related to the formalization of informal spaces, and the need to consider temporal dynamics and cross-scale approaches that compromise different goals at different geographical scales. [ABSTRACT FROM AUTHOR]

Understanding the dynamics of urban ecosystem services is a necessary requirement for adequate planning, management, and governance of urban green infrastructure. Through the three-year Urban Biodiversity and Ecosystem Services (URBES) research project, we conducted case study and comparative research on urban biodiversity and ecosystem services across seven cities in Europe and the United States. Reviewing > 50 peer-reviewed publications from the project, we present and discuss seven key insights that reflect cumulative findings from the project as well as the state-of-the-art knowledge in urban ecosystem services research. The insights from our review indicate that cross-sectoral, multiscale, interdisciplinary research is beginning to provide a solid scientific foundation for applying the ecosystem services framework in urban areas and land management. Our review offers a foundation for seeking novel, nature-based solutions to emerging urban challenges such as wicked environmental change issues. [ABSTRACT FROM AUTHOR]