Nature-Based Solutions for More Sustainable Cities – A Framework Approach for Planning and Evaluation

Although people have always been aware of the role and importance of green space, trees, and other nature in cities, wider recognition and policy support is of a much more recent date, for example in the context of current climate and public health challenges. The nature-based solutions concept has emerged as a strong, recent attempt for “mainstreaming” of nature in political, planning, and economic areas. Starting from a description of the role of nature in cities, this chapter introduces the nature-based solutions concept and its current spread and implementation in an urban context. It also raises some questions about the next steps in implementing the concept, perhaps moving away from too much focus on a utilitarian view of nature and ecosystem and toward considering nature as a framework for all planning and decision-making.

This chapter provides a brief historical review of nature-based solutions (NBS) to address increasing climate extremes in urban areas and their surroundings, tracing their historical evolution to their current moment as du jour solutions to multiple crises. We review how this term has evolved through multiple iterations used across sectors and its current ubiquity in global policy discussion forums like the United Nations (UN) Convention on Biodiversity (CBD) and United Nations Framework Convention on Climate Change (UNFCCC), due to its potential as a “swiss knife” to meet multiple global goals in climate, sustainable development, and biodiversity. We evaluate the gaps between the ubiquity of NBS in current geopolitical discourses around urban resilience and sustainability and actual implementation in cities around the world. While countries are increasingly committing to NBS and similar approaches in national climate commitments, lacking data, technical capacity, and funding continue to limit implementation beyond relatively marginal projects insufficient to shifting worsening trends in climate change and biodiversity loss. We close with four guiding principles for addressing these gaps, emphasizing the importance of connectivity and scale, assessing the direct effects of climate change on potential NBS performance, quantification and valuation, and the powerful job-creation potential of NBS in creating resilience to multiple crises, including the current global recession due to the COVID-19 pandemic.

Urban green space can be viewed as a preventative public health measure. Nature contributes to health through disease prevention, disease management, and well-being (physical, mental, and social) promotion. Those contributions are based on improvement in health determinants. Nature and green spaces have been related to more physical activity, restoration and less stress, more social capital, and ecosystem services such as better air quality, less traffic noise, less heat island effects, more biodiversity, among others. Nature, vegetation, and green spaces have also been associated with better mental health, immune system, metabolic system, pregnancy outcomes, reduced cardiovascular disease, and premature mortality. This chapter presents the connections between nature and health, describing how nature impacts key health determinants, how those health determinants are associated with health outcomes (i.e. diseases, injuries, deaths), and provides examples of urban nature interventions that have been related to public health.

Biodiversity loss now ranks as one of the most significant global drivers of environmental change. In an increasingly urbanized world, there is enormous potential to address this problem through conservation, restoration, and creation of new urban ecosystems. This chapter explores how nature-based solutions (NBS) can contribute to addressing the urgent problem of biodiversity loss in a way that goes beyond just greening gray environments. It then explores the alignment (and misalignment) between the ways in which NBS is framed as a nature conservation tool globally and the ways in which biodiversity is considered in urban approaches to NBS. Finally, the chapter explores the ways in which NBS might become an essential part of the solution to biodiversity and ecosystem decline. It discusses how NBS can be effectively leveraged to address the biodiversity crisis in urban areas, through conservation, restoration, and efforts to create thriving places for both people and nature. Although the concept of NBS in urban areas is fairly divorced from its nature conservation origins, reconnecting with those ecological roots is important for creating biodiverse, resilient cities. In so doing, NBS could offer a unified concept for environmental management in urban areas that integrates the ecological benefits of nature conservation with an innovative focus on confronting major societal challenges. Though this is a demanding task, it could provide a fit-for-purpose approach for conserving biodiversity and supporting functional ecosystems in the Anthropocene.

The assessment of ecosystem services (ES) in urban areas can be an important policy instrument for both strategic directives at national and regional levels and concrete actions at municipality level. A unifying underpinning framework that combines different administrative levels through a common, consistent basis would greatly facilitate the mainstreaming of such an instrument. Three key concepts underpin this framework: urban ecosystems, nature-based solutions (NBS), and ES. First, NBS are acknowledged as the ecological assets that in the urban context can provide ES, meant as complex processes made possible through the existence of natural and seminatural systems at various scales. Second, the classification of urban ecosystems needs to be consistent with the treatment of urban areas in ecosystem accounting and with NBS levels of intervention and primary objectives. Third, by serving societal challenges, it is important to clearly frame the strategic drivers of change: whether it concerns management practices of current land use or radical conversions in land use. Finally, once such a framework will be in place, it can facilitate sustainability assessment in urban ecosystems by quantifying the presence of NBS, whose creation/maintenance assure the delivery of ES. The purpose of this chapter is to theoretically frame an ES-based approach, but this is only a first step. Many more steps are required on to concretely put this framework in practice at different administrative levels, such as strategic planning and policy setting (at national level), and urban, peri-urban, and coastal development (at municipal level).

How are our cities confronting the challenges posed by a warming climate, the loss of biodiversity, and the increasing urban heat island effect? ― This chapter discusses the opportunities and benefits of applying the concepts of renaturalization and rewilding of cities. It introduces nature-based solutions (NBS) in urban planning that are integrated with the aim to enhance urban resilience and to slow down the biodiversity decline, which can be applied in two areas: through the conception of new green neighborhoods and through the regeneration and regreening of existing but neglected parts of the city, such as postindustrial brownfields or economically weak districts.

Contact to nature is essential for human existence, urban well-being, and a good quality of life. Green spaces in cities – big or small – all contribute to health and well-being. However, many cities do not offer residents easy access to green space within the city. Improving better access and extending gardens and parks will deliver a large number of benefits, such as ecosystem services, better water management for enhanced urban flood control, and slowing down the biodiversity loss, with the potential to restore damaged ecosystems. Furthermore, additional green space and NBS help to keep cities cool during heat waves and improve the urban microclimate.

In this context, NBS and regreening can generate significant benefits for citizens, improve urban health and well-being, and offer an opportunity to effectively deploy nature to resolve major societal challenges ― such as social inclusion, food security, and disaster risk reduction. However, it is essential that the design of NBS is fully integrated with other complementary planning interventions and seeks synergies across all sectors.

The purpose of this chapter is to discuss design principles applied to nature-based solutions (NBS) within the urban and peri-urban environment. It is divided into three parts: the first part tries to set the physical space of the interventions, with some reflections on the notion of “city,” introducing the concept of the technosphere. The second part elaborates on the concept of coexistence, particularly with respect to the attitude toward the projects, whereas the designer tries to embody the changes, either in new buildings, new plans, or even in the retrofitting of the existing urban environment, with the aim of integrating green systems within the complex built environment. The third part illustrates different case studies where, at the different scales, NBS are implemented.

The “renaturing” of cities through an increased emphasis on the use of nature-based solutions (NBS) potentially offers urban areas the opportunity to deliver multiple environmental and socioeconomic benefits. In particular, approaches linked to NBS can limit the degree of climate exposure and vulnerability impacting upon urban infrastructures. The success of NBS in addressing climate change pressures will require an improved understanding of the characteristics of environmental risk and the ability to evaluate alternate adaptive pathways. In response, this chapter explores those components which are central to effective urban infrastructure assessment and considers how they may assist in the formulation of infrastructure strategies.

We stress the need for an approach which is both scenario-focused and fully integrated within existing spatial planning frameworks. Here, we draw specific attention to the utility of strategic environmental assessment (SEA) in both embedding environmental evaluation within mainstream spatial planning and providing the basis for the comparative evaluation of alternatives. We also argue for an approach which recognizes areas of complementary interaction between “gray infrastructure” (whether existing or proposed) and approaches linked to NBS. In order to highlight examples of potential development responses, we draw on best-practice case study examples from the European Union (EU)–funded GROWGREEN project.

This contribution aims to provide multidisciplinary knowledge on the effectiveness of experimenting with nature-based solutions (NBS) for urban regeneration policy, planning, design, and governance. Specifically, the following research questions have been investigated through a cross-case study conducted in the cities of Barcelona, Copenhagen, and Marseille: What is the wider contribution of NBS for urban generation? What are the added value, the strengths, and the weaknesses of urban regeneration programs leveraging on NBS? and What is the upscale potential of NBS within selected urban regeneration programs in Europe in a post–COVID-19 scenario? The focus of the research is to create an understanding of what type of NBS development process can bring forward sustainable urban development, the different stakeholders that might be involved, the nature of their involvement, and the relationship between the actors. Three cities have been identified as most informative to explore how NBS can be valid alternatives for buildings, districts, and infrastructures redevelopment, as a starting point to foster urban resilience: Copenhagen, Barcelona, and Marseille. The results of the conducted study reveal future opportunities as well as challenges with respect to possible integrated strategies for successful codesigned and cocreated NBS for urban regeneration, especially in light of the revised post–COVID-19 pandemic urban agendas focusing on health and well-being of citizens as well as on more balanced and resilient urban built environments.

This chapter aims to further the conceptual clarity of co-creation, by classifying and exploring the spectrum of non-government actor–led governance arrangements for the co-creation of nature-based solutions (NBS) across different European contexts. Case studies from pilot demonstrators in current Horizon 2020 projects (proGIreg, CLEVER Cities, and EdiCitNet in Italy, Germany, the Netherlands, and the United Kingdom) are used to illustrate collaborative governance arrangements within the operating space of co-creation, delineate respective actor roles, and identify lessons learnt.

Nature-based solutions (NBS) generate different impacts at the urban scale, such as the ability to regulate water or store carbon, comparable to traditional, gray infrastructures in a more cost-efficient way. On the other hand, by their intrinsic nature, NBS do deliver a series of other services that are commonly defined as social, economic, and environmental cobenefits. These benefits are not always valued in a consistent and complete way, so there is the need to compile a more comprehensive evidence base on the social, economic, and environmental effectiveness of NBS. The chapter attempts to identify a categorization of the existing NBS and define the ecosystem services (ES) provided by them. Furthermore, starting from the results achieved through the definition of the existing NBS frameworks assessment, the chapter will identify a set of key performance indicators KPIs, based on the ES produced by NBS, to measure the economic, social, and environmental benefits generated in by NBS at the urban level taking into account their multifunctional character. In total, 66 key performance indicators have been individuated: 3 for provisioning services, 38 for regulating services, 17 for cultural services, and 8 for supporting services. Each indicator has been associated to a category of ES in order to measure and evaluate the performances of NBS implemented in cities.

The economic valuation of the ecosystem services (ES) provided by nature-based solutions in cities is not an easy task. In fact, various environmental goods and services do not have a market price that allows to quantify their value. This leads to an underestimation of the value of nature in cities. As a result, their critical contributions are not considered in public, corporate, and individual decision-making. The logic behind ecosystem valuation is to unveil the complexities of socioecological relationships, to make explicit how human decisions would affect ES values, and to express these value changes in units. This will allow considering the benefits provided by ES in public decision-making processes. The contribution aims to identify and analyze the most used methodologies adopted at the urban level for the valuation of ES. In total, six methodologies have been analyzed for the valuation of the provisioning, regulating, cultural, and supporting services. Finally, an interpretation framework has been defined to summarize the main findings.

While concentration of population in urban areas continues, limited contact with ecological dynamics undermines awareness on human dependence on ecosystems. However, demands on ecosystems have never been higher than in today's urbanized planet, and cities make major contributions to global environmental problems. Enhancing green and blue infrastructure (GBI) in cities can reduce the ecological footprints of cities, while enhancing urban resilience and quality of life for their inhabitants. Urban GBIs provide multiple benefits to people in the form of ecosystem services (ES) and hold potential for providing nature-based solutions (NBS) to address urban challenges.

To adequately evaluate the ES provided by GBI, researchers have recently advocated integrated valuations. Integrated valuations aim at overcoming the limitations of the traditional single discipline and narrow approaches, by considering the multiple ways in which humans benefit from nature across the economic social and cultural domains.

In this chapter, we present examples of integrated valuations of ES in two Spanish cities, Barcelona and Bilbao. Both examples combine different valuation techniques and metrics, both monetary and nonmonetary, to account for the ES provided by urban GBIs and to assess their potential as NBS.

Our case examples show that urban GBIs provide many valuable benefits to urban dwellers. One of the clearest outcomes from these infrastructures is cultural ES, especially the multiple recreation and leisure opportunities they provide, which in turn has a remarkable positive effect on human health and well-being.

Public spaces within our cities are being redefined through a wide range of nature-based solutions (NBS) including green spaces. In this chapter, we will focus on public green spaces in the wider sense. If well planned and managed, green spaces can promote social inclusiveness by enhancing the livebility of neighborhoods and promoting the development of social interactions. The creation of new green space does not automatically lead to socially just and inclusive development; co-benefits should be available and accessible to the entire community. Prejudices, marginalization, and discrimination on socioeconomic condition, ethnicity, religion, gender, age, or disability still prevent the equitable distribution of these benefits and need to be fully understood before any planning process is undertaken. The governance of public green spaces is still viewed primarily as a matter for the state or as a purely private activity. It is important, therefore, to identify ways to ensure the integrated and transdisciplinary participation of diverse actors, as is shown in some examples from different countries. The planning and design of green interventions should start with the evaluation of existing or potential trade-offs between environmental and social development. Urban green spaces must be designed as places for multiple and diverse social groups. If all these issues are duly considered and addressed, NBS can serve as climate mitigation and adaptation tools that produce co-benefits for societal well-being, thereby serving as strong investment options for sustainable urban development and making our cities green, healthier, and happier places to live.

This chapter is in line with the strand of literature on urban environmental stewardship and examines how cities around the world have been teaming up with each other in order to foster cocreation and codeployment of nature-based solutions (NBS) to tackle global environmental challenges and promote climate-resilient communities. This chapter describes such an effort that cities made to build international alliances and networks as a new wave of “city diplomacy.” Indeed, recent environmental negotiations at the global level on sustainable development and climate change have proven how cities of different size, with diverse socioeconomic and environmental conditions, were able to put NBS on the agenda and show their transformative power for the common good. Throughout the chapter, the European policy context is always placed at the meso level, between the macro (international arena) and the micro (city) dimensions, in order to demonstrate how the European Union has been instrumental in connecting the global, regional, and local agendas on NBS for renaturing cities.

Economic and market-based instruments are not “the” answer for nature-based solutions (NBS) in cities, but they are “part” of the answer. Regulatory instruments are needed when specific behaviors must be avoided. Voluntary instruments may be effective, especially at the local scale, but do not often guarantee the pursued performance result. Economic instruments, if well designed, implemented, and used, often have a comparative advantage in terms of efficiency and performance. They are also a source of funding for financing NBS. Too many policy experts and decision-makers are ready to propose public expenditure and subsidies, including for urban policies, and for policies in favor of natural capital, ecosystems services, and biodiversity. Yet, they too often forget to indicate where the revenues to finance the initiatives must come from, however excellent and ambitious they might be. Without using also economic instruments in the policy portfolio, many objectives for sustainable cities will be much more difficult to achieve, especially in the perspective of the Paris Agreement on climate change and of the UN Agenda 2030 with its Sustainable Development Goals.

Chapter 17 discusses challenges for financing nature-based solutions (NBS). Financing NBS is a key challenge to ensure scaling of the use of NBS in urban areas. This is mainly due to the difficulty to monetize the value generated through the provisioning of ecosystem services, as well as the multiple cobenefits that NBS provide. Certain types of NBS, such as green roofs, have been able to allow for private value capture, enabling such projects to attract private or blended capital. Others, where benefits are generally regarded as public good, have to rely on different financing strategies and instruments. The section provides an overview of financing solutions (public, private, and blended instruments) for different types of NBS and their applicability to NBS in the urban context.

The nature-based solutions (NBS) integrated in urban open spaces are a precious tool that provide better and wider ecosystem services in cities. An ecosystemic approach in planning, designing, and also managing green areas furthermore helps to improve the whole quality of life and perceived well-being of the citizens, increasing too their sense of belonging and fostering the neighboring communities. Under this point of view, greenery should not be considered as a cost but as an investment of public money finalized to improve the quality of life in the cities especially in facing climate change.

A comparison between costs and benefits produced by the green features in the cities allows to evaluate the advantages to include those solutions in planning and designing urban green areas. In the following chapter a step-by-step procedure is proposed to assess the ecosystem services provided by green areas in cities, compared to design, building, and maintenance costs. Some national and international examples are provided too.

Nature-based solutions (NBS) are increasingly seen as a holistic approach to a wide array of environmental and societal problems. Crucially, much of its appeal stems from its potential to address multiple challenges at once, being not only valuable for their positive impacts toward sustainability and human welfare but also their cost-effectiveness when compared to some engineered solutions. This helps to explain the growing awareness of the private sector of the market opportunities arising from the introduction of NBS to their operations. This chapter presents some of the opportunities for businesses in implementing NBS, such as the risk and cost reductions, compliance with regulatory requirements, reputational and financial gains, among others. I will also introduce some of the challenges they might face, such as the difficulties for companies to fully internalizing all benefits generated by investing in NBS, the need for long-term planning in adapting NBS in a company's operations, possible hindrances in financing innovative NBS, among others. The chapter will also showcase NBS being implemented by companies in urban contexts, based on the responses of local governments that disclose to CDP's cities questionnaire. This concluding section of the chapter provides policy recommendations for public entities to incentivize the uptake of NBS by the private sector.

The Ruhr region is a long-term showcase for the implementation of nature-based solutions (NBS) as part of regional and local development policies. With the implementation of the Emscher Landscape Park and the ecological renewal of the Emscher River System, a fundament for new and integrated strategies and projects was created. The Ruhr Region was inspired by the models, strategies, and discussions of the EU to test and implement ES, NBS, and GI in the last 10 years. The planners were also following the two competing national discussions in Germany to interpret GI more in the context of sustainable urban development or more as nature protection and biodiversity. In 2016, the Ruhr Region published a first own GI strategy named Green Infrastructure Ruhr, which was designed as an integrated and multi-level strategy with five operative fields of action for the whole region: (1) Urban Landscape, (2) Water in the City, (3) Green Urbanism, (4) Climate-friendly Mobility, and (5) Climate Protection and supporting Energy Efficiency. The conceptional and political discussions about this approach in the region are still going on. The author recommends changing the perception of NBS from green conceptual and academic perspective to operative policy and management. NBS can be developed as real urban infrastructures. Our societies are well trained to run, to finance, and to maintain various infrastructure systems. It is time to take operative responsibility for NBS in our cities and regions.

The proverbial administrative complexity of Paris and its region, which also includes a metropolitan authority since 2016, has not prevented multiple and rapid changes to take place in the last decade. A national government decision has initiated the construction of a new regional metropolitan public transportation infrastructure that has leveraged more than €15 billions of green bonds. Mounting environmental challenges are triggering new societal priorities and legal changes, heightened by the COVID-19 crisis context. Since 2014, projects and plans led by local governments to value nature-based solutions (NBS) have met a rising interest from national and international investors and developers, in a context of multiple climate and biodiversity initiatives from the private sector and the civil society. However, assessing their long-term value remains a challenge for both governments and researchers while the calls for nature to remain a common good stir new forms of vigorous social engagement. The Paris case shows that the art of creating NBS that maximize biodiversity and support CO₂ reduction at large metropolitan scale depends on two priorities. The first is strengthening global commitments. The second is refocusing existing massive investments in grey infrastructure systems, so far major drivers of public investments, as infrastructure for distribution, unlocking local biodiversity valuation potential, and supporting social innovation.

Even though following the laws of nature to construct harmonious nature–human interactions has long been one of the most influential philosophies in Chinese history, nature-based solutions (NBS), an innovative concept referring to the sustainable utilization of nature in solving various social and environmental challenges facing contemporary societies, can hardly be found in research papers and practices in Chinese context until very recently. Yet, some NBS features, and also NBS thinking, have already been successfully embedded within many environmental management decisions and practices, which are commonly characterized by (1) prioritization of nature preservation/restoration to economic activities and (2) functionalization of nature as a countermeasure to environmental and/or social issues. This chapter will present a comprehensive overview of the Beijing Afforestation Scheme, an exemplar case of NBS in the Chinese context. Starting from a description of Beijing and this massive afforestation project, it delineates major characteristics of this NBS, signified by (1) a shift from outcome-driven to integrated ecological resilience, (2) a change from recreating tree rows to restoring natural boreal forest, and (3) an evolution from top-down to adaptive and inclusive governance. Lastly, lessons learnt and future challenges are discussed.

New York City, the most dense and populous city in the United States, is one of the world's most altered landscapes. Yet, New York City boasts an urban ecology which produces invaluable environmental benefits. The extent and vitality of its green and blue spaces would not be where it is without the unrelenting organization, stewardship, and advocacy of the New York citizenry.

Born from these grassroots environmental justice movements, citizens have built the nature-based solutions (NBS) they seek out of oft-neglected landscapes and vacant lots. Today, over 800 civic environmental stewardship groups are active across all of New York City's 205,000 acres. These groups directly manage, restore, and conserve greenspaces, as well as advocate for their investment and expand ecological awareness through educational programming and campaigns, and their work is more important as ever, with the growing impacts of climate change. This chapter will review three cases of community environmental stewardship, including a distributed community garden movement, restoration of a polluted waterway, and an emerging framework for adaptive coastal protection. Through these cases, we may understand the origins and frontiers of some of today's civic networks stewarding New York City's natural areas. These cases emphasize a socioecological view of the city's ecology. They show that we must consider green infrastructure and natural resources as places which have social and cultural meaning, not merely spaces with ecological functions. They highlight the labor and investments committed by community groups which require compensation and nurturing. Lastly, they demonstrate the importance of supporting social networks and local capacities in stewarding nature-based strategies and building resilient, adaptive, and equitable socioecological systems.

This chapter discusses the DRENURBS initiative in Belo Horizonte, a program for urban water drainage using natural ecosystems, using the sociotechnical framework. DRENURBS transformed the logic of canalizing water streams into a new, nature-based solution with significant positive impacts on biodiversity and social benefits. Following a theoretical debate on sustainability transition and innovation concepts, this chapter seeks to map the essential elements for building a successful institutional framework in the public sector for urban biodiversity improvements.

This chapter highlights how cocreation processes have been applied for the implementation of nature-based solutions (NBS) in different organizational systems, governance, and cultural settings around the world. The cases are from Peru, the United States, and Korea. The cases show how collaborative governance arrangements for NBS have played out in different contexts. Finally, reflections on the cases are carried out considering the perspectives and limitations of cocreation for NBS delivery.