Cities around the world are undergoing significant transformations and are facing substantial challenges in the form of urban densification and extreme weather conditions, due to climate change and the ongoing urbanisation. In Europe, more than 70% of the population is already living in urban areas. Nature-based solutions (NBS) are becoming an effective tool for such eco urban regeneration, but their social impact is being questioned as a form of green gentrification in certain communities. The European Commission defines NBS as ‘solutions that are inspired and supported by nature, which are cost-effective, simultaneously provide environmental, social and economic benefits and help build resilience’.
This page is part of an ongoing, open-ended online collaborative database, which collects relevant approaches that can be used by city-makers to tackle unsustainability and injustice in cities. It is based mainly on knowledge generated in EU-funded projects and touches on fast changing fields. As such, this page makes no claims of authoritative completeness and welcomes your suggestions.
General introduction to approach
Nature-based solutions (NBS) have been examined in a number of research projects that involve stakeholders, as a way to make cities greener and more sustainable. Looking at NBS as the way forward in sustainable urbanism, projects have also looked at barriers that prevent the wider implementation of NBS and have examined potential means of overcoming these barriers. For example, a justice-based analysis examines questions of social equity in relation to the impact of NBS and related City Greening initiatives.
Examples of NBS inspired and supported by nature are numerous, including: green roofs and city parks that can limit heat stress; city lagoons that store water; and permeable surfaces, vegetation and rain gardens to intercept stormwater. NBS can deliver multiple benefits such as multi-functional green spaces that support adaptation to climate change while also being used for sports and recreation, as well as serving as places for local distinctiveness, increasing the aesthetic appeal of a neighbourhood, and providing a sense of community.
As NBS is a relatively new concept in research and policy, the impacts of implementing such approaches are only recently starting to crystalize. The NATURVATION (Nature Based Urban Innovation, 2016-2020) project outlined that despite their significant potential, the use of NBS solutions remained marginal, fragmented, and highly uneven within and between cities. The CLEVER Cities (2018-2023) project has identified ten key barriers to NBS implementation: 1) Limited knowledge base for nature-based solutions. 2) Inadequate governance structures. 3) Balancing the multiple goals NBS can deliver. 4) Effective citizen involvement. 5) Insufficient social inclusion. 6) Insufficient social acceptance. 7) Lack of political support. 8) Lack of financial support. 9) Monitoring challenges. 10) Upscaling difficulties. The GrowGreen project seeks to embed NBS in long term city planning, development and management, so that accessible green and blue spaces are a permanent feature of all urban areas. Many approaches have identified the need for local communities’ active participation in the creation of NBS, which the URBAN GreenUP (New Strategy for Re-Naturing Cities through NBS, 2017-2022) project identifies as the core of urban green regeneration. GREENLULUS (Green Locally Unwanted Land Uses, 2016 – 2021) project further explores if, and attempts to measure the extent to which, greener cities are less racially and socially equitable or whether greening projects tend to increase environmental inequalities.
Shapes, sizes and applications
The approaches vary widely in scope and size. A number of efforts have been made to systematically organize examples, and research findings around NBS and their implementation:
It is quite common that NBS projects would use the Living Labs approach to develop solutions with and by local communities in front-runner cities, and then try these approaches later in follower cities, such as the ProGIreg (productive Green Infrastructure for post-industrial urban regeneration) project, that is active since 2018 in urban areas that lack quality green spaces and suffer from social and economic disadvantages, inequality and related crime and security problems. Through interconnected projects, it will implement 8 types of NBS: 1) Leisure activities and clean energy on former landfills 2) New regenerated soil 3) Community-based urban farms and gardens 4) Aquaponics 5) Green walls and roofs 6) Accessible green corridors 7) Local environmental compensation processes 8) Pollinator biodiversity.
Nature4Cities (NBS for re-naturing cities: knowledge diffusion and decision support platform through new collaborative models, 2016 - 2020) is creating a comprehensive NBS reference Platform to empower urban planning decision-making based around new governance and collaborative models driven by citizens, researchers, policymakers, and industry leaders. They distinguish 3 distinct levels with the following list of NBS examples:
- NBS at building or plot level: Permeable paving | Urban meadow | Private garden | Shelter for auxiliary fauna - insect hotel | Use of auxiliary fauna - Earth worms | Climber covered green building | Sustainable urban drainage system | Green roof and meadow | Combined solutions - Green roof with renewable energy | Rooftop farming
- NBS at neighborhood or district level: Cemetery | Pedestrian way with sand | Green wharf | Spontaneous flora | Street trees | Permeable riverbank | Community garden | Water body | Urban park
- NBS at city level and beyond: Urban farming | Constructed wetland | Beehive | Green street network | Urban forest | Ecological corridors | Urban planning
A similar effort is the Urban Nature Atlas, from the NATURVATION project, which maps 1000 examples of Nature-Based Solutions from across 100 European cities, and provides information on the key challenges they address, the type of urban setting they are implemented in, their cost, management set-up and type of financing source.
UNaLab (Urban Nature Labs, 2017 – 2022) is aiming to develop smarter, more inclusive, more resilient and increasingly sustainable cities through innovative NBS. It focuses on urban ecological water management, accompanied with greening measures and innovative and inclusive urban design. The UNaLab consortium centered around a diversity of stakeholders from 10 cities across Europe and beyond, including municipalities, research, business and industry, some cities some are more implementation-oriented, others are more assessing/observing how NBS are realized, so as to later replicate in a different context.
The GREEN SURGE (Green Infrastructure and Urban Biodiversity for Sustainable Urban Development and the Green Economy, 2018 - 2023) project is a collaborative project between 24 partners in 11 countries, they will produce a Manual for Urban Green Infrastructure Planning, which will be aimed at planners, policy-makers, and other practitioners. URBAN GreenUP also involves European and non-European partner cities with the aim to mitigate the effects of climate change, improve air quality and water management: Three European cities will assume the demos as front-runners (Valladolid, Liverpool and Izmir), other set of two European cities will act as followers to strengthen the replication potential of the results (Ludwigsburg and Mantova) and finally three non-European cities (Medellín, Chengdu, China and Quy Nhon, Vietnam) will allow to identify the market opportunities for European companies out of Europe and fostering the European leadership in NBS implementation at global level. They are grouped into four main categories: re-naturing urbanization, water interventions, singular green infrastructures and non-technical interventions.
Relation to UrbanA themes: Cities, sustainability, and justice
All approaches have a very high urban focus, but the level to which justice is addressed varies greatly. Most research projects are concerned with the direct implementation of NBS or the development of tools to assist in the process. While some approaches attempt to create citizen driven, bottom up processes that seek to include the highest level of community engagement in the process, some also aiming at NBS providing improved economic opportunities for disadvantaged communities. GREENLULUS stands out as a unique project that seeks to understand the impact of NBS and related urban processes on certain communities, as creating or exacerbating inequalities in the form of green gentrification.
Sustainability issues addressed by a high number of approaches include climate and water resilience responding to flooding, heat stress, drought, poor air quality, biodiversity, the carbon cycle, soil consumption and use of natural resources in urban environments, citizen involvement, education and empowerment. Regarding the linkage of sustainability and justice, this approach has an overall high level, but from different aspects. On the one hand, NBS aim at increasing availability of green/blue spaces which are beneficial to all people, some address explicitly disadvantaged areas, so mend past injustices in underprivileged neighborhoods, and some aim specifically at including/addressing the needs of vulnerable groups (like children, the elderly). However, on the other hand, counter-effects of NBS (like gentrification) are only now beginning to be studied as drivers of injustice, and wider issues of uneven patterns of participation in public debate/workshops/consultations continue to persist and express also in NBS projects."
Narrative of change
With increased problems arising from climate breakdown (flooding, drought, food shortage) along with rapidly increasing urban transformation, how can NBS and other forms of Green and Blue Infrastructure best respond to modern cities urban climate challenges?
These approaches seek to respond to the urgent challenges of climate mitigation and adaptation by using NBS in urban areas, so as to achieve as rapidly as possible more sustainable, resilient and just cities and communities. Having identified that many NBS remained marginal, fragmented, and highly uneven within and between cities, many projects that involve city stakeholders are taking steps to employ bottom-up, community-led approaches that involve local communities to the highest degree in the co-design, implementation and ongoing upkeep of NBS. Many approaches work at a series of scales, to see NBS as tools of connections between currently disconnected urban communities, especially in post-industrial areas, where solutions also include improved economic opportunities through outputs from the urban solutions, such as selling honey in ProGIreg’s Pollinator biodiversity NBS.
Most approaches have high transformative potential, seeking to act in currently problematic post-industrial urban areas, engaging and facilitating citizens to become involved in the urban regeneration of Green and Blue areas in their localities, to develop community dynamics to take collective ownership for these areas and in some instances bring about a situation where NBS can offer new economic opportunities. Such community engagement can have a catalyzing effect, leading to organized local communities having greater say in future scenarios for their territories. The development of urban (green) corridors can physically improve connections with surrounding local areas facing similar challenges and general health benefits that will increase with time. The GREENLULUS approach questions certain aspects of NBS, suggesting how deeper questioning of justice in urban re-naturing and new strategies can be developed to identify and resist the negative aspects of NBS.
Illustration of approach
The GREENLULUS approach is most aligned to the chief line of investigation of the UrbanA project. GREENLULUS analyzes the conditions under which urban greening projects in distressed neighbourhoods redistribute access of environmental amenities to historically marginalized groups. The study takes place in 40 cities in Europe, the United States, and Canada. The research assesses the extent to which urban greening projects such as parks, greenways or ecological corridors encourage and/or accelerate gentrification, given such projects have been recently shown to be factors contributing to residents’ exclusion and marginalization. Through an innovative FUG (Fair Urban Greening) index, it analyzed which cities most equitably distribute the benefits of greening. They also provide new tools for municipal decision-makers to conduct an environmental equity performance analysis of new or restored green amenities. Lastly, their research included an in-depth analysis of cases of community mobilization and contestation, and of the policies and measures that municipalities develop to address exclusion in “greening” neighbourhoods. Their hypothesis is that the social and racial inequities present in sustainability projects make green amenities Locally Unwanted Land Uses (LULUs) for poor residents and people of color.
NATURVATION’s Urban Nature Atlas maps 1000 NBS examples from across 100 European cities, 2 of which include:
- Urban gardens of Poblenou (Horts indignats del Poblenou)
It is a community garden initiated by the autonomous assembly of the Poblenou neighborhood. It has changed location a number of times, eventually occupying the empty lot of demolished buildings. Over time the garden expanded taking over an adjacent empty space, as well as other yards in the neighborhood. The garden is not maintained for strictly productivity purposes, especially because much of its soil has been contaminated by a soap factory. It is rather used as a space for social encounter and knowledge sharing on planting and working with the earth on communitarian basis (1 and description provided by CEU).
- Lisbon Biodiversity Route (Rota da Biodiversidade)
Pedestrian route with 14 km,marked according to the norms of the Portuguese Federation of Camping and Mountaineering, connects the Forest Park of Monsanto to the Tejo river, which aims to contribute to raising awareness of the capital's biodiversity.(ref. 4). The position and expressive dimension of these connected areas is decisive in the regulation of the climate,quality of the air and in the diversity of habitats that the city offers for the proliferation of life. The Biodiversity Route is a circular route, which can be done on foot or by bicycle in each,species of fauna and flora that can be observed.
- GREENLULUS: Green Locally Unwanted Land Uses http://www.bcnuej.org/projects/greenlulus/
- ProGIreg: Nature-based solutions and green infrastructure http://www.progireg.eu/nature-based-solutions/background/
- NATURVATION https://naturvation.eu/
- CLEVER Cities http://clevercities.eu/
- GrowGreen http://growgreenproject.eu/
- URBAN GreenUP https://www.urbangreenup.eu
- GREENLULUS http://www.bcnuej.org/projects/greenlulus/
- ProGIreg: Nature-based solutions and green infrastructure http://www.progireg.eu/nature-based-solutions/background/
- Nature4Cities https://www.nature4cities.eu/
- NBS reference Platform http://www.nature4cities-platform.eu/
- Urban Nature Atlas https://naturvation.eu/atlas
- NATURVATION https://naturvation.eu/
- UNaLab https://www.unalab.eu/
- GREEN SURGE https://greensurge.eu/
- Pollinator biodiversity http://www.progireg.eu/nature-based-solutions/pollinator-biodiversity/
- Urban gardens of Poblenou https://naturvation.eu/nbs/barcelona/urban-gardens-poblenou
- Lisbon Biodiversity Route https://naturvation.eu/nbs/lisboa/lisbon-biodiversity-route