Other funding sources are unclear

The Mobile Tree Trail is a nature-based solutions (NBS) initiative aimed at preserving Mobile, Alabama’s urban forest while celebrating its cultural and ecological heritage (Ref 1, Ref 2). First established in the early 1990s by volunteers, the original trail featured 24 iconic trees, selected for their historical significance, environmental value, and beauty (Ref 1, Ref 2). Over the years, some trees were lost to development and storms, and the trail faded into obscurity (Ref 1, Ref 4).
From 2021, the Mobile Tree Commission, with support from The Nature Conservancy, is leading efforts to revive the trail (Ref 3, Ref 6). Activities include reviewing past entries, opening public nominations, and selecting new trees that best represent Mobile’s identity (Ref 3, Ref 4). The project emphasises inclusivity and public participation, welcoming volunteers and local input to shape a trail that evolves with the city (Ref 4, Ref 6).
Mobile faces environmental threats such as hurricanes, urban expansion, and loss of native tree cover (Ref 1, Ref 6). The revitalised trail helps address these challenges by promoting awareness, conserving old-growth specimens like the 300-year-old Duffie Oak, and maintaining vital green spaces (Ref 4, Ref 6).
The Mobile Tree Trail blends education, tourism, and conservation, enhancing urban resilience while telling the city’s story through its trees (Ref 3, Ref 6).

HortaFCUL is a project created and managed by the Faculty of Sciences at the University of Lisbon to raise awareness and promote the practice of permaculture as a solution to the ecological, social, and economic problems the world is facing (1). This initiative began in 2009 on the University campus through a garden, which allowed HortaFCUL to start conducting some activities that could answer some socio-environmental challenges, such as food security and sovereignty, ecosystem degradation and climate change (13), by raising awareness, teaching, and practising many aspects involved in permaculture and urban agriculture (2). Its focus has been on regenerating soil in an urban environment and creating productive landscapes for people and other beings (12). They grow different types of plants (vegetables, shrubs, trees) in different ways (swales, raised beds, greenhouses) to increase plant diversity and foster ecosystems (13).
The project is managed by students and researchers, who hold educational activities, such as courses, workshops, and dissemination activities (events, discussions, fairs, and conferences) (2). The project is organised according to a non-hierarchical sociocratic model, in which all decisions are made as a group, and where all ideas, critiques, and suggestions are seen as added value and an opportunity to improve techniques and knowledge (3). Additionally, it is open to the community, allowing anyone interested to participate and volunteer (1).
HortaFCUL is also one of the pioneering permaculture projects in operation in the Lisbon region and is now recognized as a national reference centre for permaculture (2). Since its inception, HortaFCUL has sought to be a hub that attracts people, organizations, and other initiatives, and it is currently a point of contact between different projects and associations, such as local businesses, educational institutions, and networks (5).

The urban garden in Miraflores park (Huertas las Moreras) was established already in 1991 on an old waste dump and contains 10500 m2 of plots for locals to grow fruits and vegetables [Ref. 1]. The creation of the gardens was initiated by citizens who formed an association and implemented it in cooperation with the City of Seville. The citizens were discontent with the lack of green space in the area, and the urban gardens came to be alongside Miraflores Park, which was also pushed by the locals. The initial goals of the gardens were to allow locals to produce their own food and to host educational activities [Ref. 2]. More recent developments exemplify the focus on education and knowledge. In 2022, the citizen science project "Planta Bienstar" was carried out in the gardens, where high school students measured the lead levels in the soil and crops. The project aimed to investigate if lead levels posed a health risk and if the gardens could reduce levels over time. The project was organised by the non-profit Descubre Foundation and funded by the foundation and the regional Government of Andalusia. The project relied on the knowledge and efforts of the citizens, the students and gardeners in an intergenerational collaboration where the young could learn methods from their elders [Ref. 3, 4].

The Swedish Geotechnical Institute, a government agency, and the county administrative boards in Västra Götaland and Scania are running a project which tests methods to prevent erosion of coastal salt meadows. Erosion risks destroying unique ecosystems, and the aim is to develop cost-efficient, nature-based mitigation methods that can be replicated in other sites with similar problems. The project is part of an EU-funded Interreg North Sea project called MAinstreaming NAture BAsed Solutions through COASTal systems (MANABAS COAST), which involves other countries in the region [Ref. 1, 5]. Four different salt meadows are included in the Swedish part of the project. The sites are called pilot areas and are meant to test and showcase NBS to inform policy and develop methods that can be used in larger scales in the future. One of the sites is located at Glose in Kungälv municipality within the Gothenburg FUA [Ref. 2-4]. Here, the biodiversity of a salt meadow used for grazing and the adjacent coastal waters are threatened by erosion. According to a new management plan, NBS such as natural barriers will be implemented to break waves and halt erosion, preserving the ecosystems, improving water quality and ensuring the land continued use as a pasture for grazing cattle [Ref. 4].

Mapinguari National Park, located in the Amazon region of Brazil, is a protected area distinguished by its rich biodiversity and vast expanse of untouched tropical rainforest (2). It was officially created on June 5, 2008, by decree, covering an area of 1,776,914.18 hectares (2). The Chico Mendes Institute for Biodiversity Conservation (ICMBio) manages the park. It is linked to a management plan encompassing several nearby conservation units and their areas of influence (2, 3). Its main goal is to preserve the valuable natural ecosystems and scenic landscapes of the Purus-Madeira interfluvial region, which includes savanna enclaves (2, 3). The ecoregion where it is located has a high priority for botanical conservation due to parameters such as species richness and endemism (3). Additionally, the area presents great environmental heterogeneity, with several isolated and unique ecosystems, aspects that have been considered for fostering scientific research and public visitation, with programs for environmental education, recreation in contact with nature, and ecotourism (3). On March 8, 2013, an advisory council for the park was established to involve various stakeholders in decision-making and the effective conservation of the park (2), and in 2018 a Management Master Plan was established, seeking to develop an integrated approach for the protection and proper management of the region, especially considering the socio-environmental impacts of the construction of the BR-319 highway and the deforestation caused by fires, the expansion of soybean cultivation, land appropriation (7) and cattle ranching from the neighbouring state (3, 10). It was established as a Natural Park in 2008, but over the years it has undergone changes in land regulations, adding or decreasing its size as certain mining activities have been allowed in the buffer zone (2)

Eliseo Collazos is located in the coastal desert ecosystem of the Lomas or ‘fog oasis’, an area that receives less than 10 mm of rainfall per year. Vegetation cover is of particular importance in the hills surrounding Lima, as it provides critical solutions to erosion, landslides and soil degradation in the ecologically degraded ecosystem of the Lomas. However, this ecosystem is facing risks from urbanisation, illegal mining and agricultural practices, resulting in the lack of the delicate mist-fed greenery for which the Lomas are known (2). This has led to increased particulate matter in the air due to exposure to sand and wind, aggravating respiratory diseases such as tuberculosis, which is prevalent in Lima's informal communities (2).
Low-income communities have inhabited this area, forced to migrate from the rainforest, highlands and city to the desert slums (4), who have only been able to settle in these landscapes with little access to resources, prone to disaster risk, little public investment in infrastructure and little access to green spaces (2). As a result, these communities live in poor conditions (1). For this reason, in 2013, the University of Washington, under its Urban Informal Communities Initiative programme (1), initiated a participatory project that sought to address the challenges faced by the inhabitants of this area (1, 2). In a series of participatory workshops, residents identified greenspace and food security as top priorities in their community; the Gardens, Greenspace and Health project responds to these priorities as an initial step towards the expansion of greenspace, agriculture and ecological restoration in and around the Eliseo Collazos community (2, 4).
Although individual families constructed them, the front yard gardens contribute to a shared public realm and community greening (4). The general project also involved the installation of fog catchers and the creation of common recreational spaces (4).

At the beginning of the twenty-first century, Kunming’s urban planning faced major challenges, including fragmented development, environmental degradation, and limited green spaces (Ref 1). In response, the municipal government launched a series of strategic plans aimed at promoting high-quality urban development and environmental restoration.
Baisha Lake was identified as a key area in these strategies, with plans for Baisha Lake Park first highlighted in 2017 (Ref 2) and reaffirmed in the "Opinions on Supporting High-Quality Development in Kunming" in 2021 (Ref 2). To implement parts of this broader strategy, the government entered into public-private partnerships. In 2018, land development rights for parts of East Baisha Lake were granted to Dahua Group, on the condition that 40% of the area be reserved as green space and that ecological restoration efforts be undertaken (Ref 3, 4).
The Eastside Baisha Lake Park project, launched by Dahua Group in February 2023 (Ref 3, 5), is thus one component of this larger government-led urban renewal effort. The project follows the city's planning framework of “one lake, six zones, 46 scenic nodes” and includes 55 hectares of green space, with 40% designated as parkland. By the end of 2023, 6.5 hectares had been completed, and the south bank of the park opened to the public in September 2023 (Ref 3, 6).
The broader East Baisha Lake area's development was originally planned by the state-owned Kunming Urban Construction Company, but land rights were later transferred to Dahua Group. Thus, while a private developer is leading the construction, the project remains a part of Kunming’s publicly driven strategy to restore the lake and enhance urban livability.

The Vera Park is a significant site in the city of Tbilisi, created in the mid-20th century. Located centrally, it is not only frequently visited by tourists but also used as a recreational area for the surrounding residents and workers (Ref. 1,2). The park is recognized as an immovable cultural heritage site, emphasizing its historical significance (Ref. 1). However, its condition had become quite desolate, necessitating extensive rehabilitation while preserving its original features (Ref. 2). Importantly, the project is carried out between the city of Tbilisi and the Asian Development Bank under the Livable Cities Investment Program (LCIP) to improve urban and tourism infrastructure (Ref. 1,2). As such, the project was developed through co-participatory planning, engaging citizens who have shown significant interest in the site’s development and will further serve as a precedent case for co-participatory planning in the future (Ref. 4,2).

The Africatown Connections Blueway project aims to create a recreational water trail by linking 14 culturally and historically significant points along a 10-mile route (Ref 1). Central to this initiative is the preservation of Africatown's rich heritage and natural resources. The project seeks to reconnect residents of Africatown, descendants of the original founders of this self-governing community, which maintained a strong sense of African cultural heritage, to waterways that were historically vital for food, transport, and spiritual practices (Ref 1). By restoring access to these waters, the community can address both environmental and social issues, promoting eco-tourism and business growth while safeguarding cultural heritage (Ref 2). Local leaders emphasize the environment’s role in healing the community and preserving history, highlighting how this initiative can provide economic opportunities and improve quality of life (Ref 2). The project seeks to address the environmental injustices that Africatown communities have endured for decades. The area surrounding Africatown has long been dominated by harmful industries, including aluminium plants and paper mills, which have heavily polluted the water and restricted residents' access to it (Ref 1). With support from the National Park Service and contributions from Mississippi State University, the Blueway transforms neglected river access points into recreational areas, promoting environmental stewardship and cultural awareness (Ref 2).

Barranco, the smallest district of Metropolitan Lima, is suffering from serious environmental problems that are affecting its inhabitants. Environmental degradation is a consequence of the increase in large buildings (real estate boom), which reduces green space areas and causes a deficit of vegetation in the district. Additionally, there are high levels of air pollution due to car traffic, which has been accentuated by the lack of green areas in the area, which affects the environmental quality and the population's quality of life (1).
Additionally, the district doesn't have more free public areas where new green areas can be created. Due to these combined pressures, the local government has looked for alternatives, considering private areas, which have a high potential to implement green roofs and vertical gardens, which can contribute to face Climate Change as a mitigation strategy and improve the quality of life (1). The Green Roofs and Green Walls strategy is proposed to build citizen culture, nature appreciation, landscape, and ecosystems (2, 3). The aim is, therefore, to encourage the inhabitants of the district to progressively install green roofs and walls, employing an economic incentive in the taxes paid to maintain public green areas (4).
The programme is oriented to generate environmental benefits such as the reduction of air pollution, acoustic insulation, thermal comfort, and increase of green areas (m2) per inhabitant, and social benefits such as the improvement of the living conditions and health of the inhabitants of the district (1, 3), the promotion of social relations (1), the aesthetic improvement of the city, and the possibility of producing food for self-consumption, as there is support in the implementation of hydroponic systems in the green walls and roofs (1, 3). Its implementation focuses on new, under construction or existing residential, commercial, office or lodging buildings (3).