Expected improved air quality

The project La Ruée Verte aims to create a green corridor connecting two emblematic locations for social and environmental justice: La Base Marseille and L’Après M. The route spans over 7 km and passes through La Friche de La Belle de Mai and aims to bring more nature into the city on a larger scale in a fair and equitable way (Ref 2).
Given the challenges of climate change—rising temperatures, urban heat islands, fewer trees in Marseille, and increasing urbanization—the green corridor will offer a solution to combat the suffocating effects of the city’s concrete sprawl (Ref 2). Additionally, it aims to reduce pollution peaks and improve air quality (Ref 2), increase biodiversity (Ref 2), and provide access to green spaces and places for social interaction (Ref 2).
The project also addresses the broader social crisis, with rising costs of food, housing, and transportation (Ref 2). Local solidarity is key, ensuring that all green initiatives foster community interaction and consider the urgent needs of residents, such as precarious living conditions and isolation (Ref 2). Collective participation is central to the project, ensuring that it is designed by and for residents of different neighborhoods, reflecting their realities. The project, called “La Ruée Verte,” aims to unite various citizen groups, social centers, and associations to amplify their voices (Ref 2).
The project's first phase, “La Petite Ruée,” will launch in October 2024, following a year of preparation. It will start with neighbourhood micro-projects and shared advocacy, including events and gatherings (Ref 2). The goal is to collectively think about social and climate justice and begin taking concrete actions towards popular ecology in each neighbourhood (Ref 2).

Minimizing heat stress is a top priority for Phoenix, the hottest major city in the U.S. In 2023, extreme heat contributed to at least 359 deaths across Maricopa County. Phoenix is particularly vulnerable to climate change, with extensive concrete and asphalt, increased pollution, higher population densities, and concentrated infrastructure that exacerbate the urban heat island effect, drought, and extreme weather. Moreover, the heat disproportionately impacts lower-income and Hispanic neighborhoods, which tend to have less tree canopy and fewer resources to cope with rising temperatures.
To address these challenges and promote tree equity in underserved neighborhoods, the City of Phoenix, along with the Office of Heat Response and Mitigation, launched the Community Canopy Grant Program in 2023. The concept of tree equity refers to identifying areas with low tree coverage and high social need, then prioritizing investments in these areas. By improving tree equity, the program aims to assist neighborhood associations and community members in areas that need it most.
The Community Canopy Grant Program targets neighborhoods within Qualifying Census Tracts across Phoenix, and one of the first neighborhoods to benefit was Westwood. In early 2024, community members gathered to plant 200 box trees for residents who received grants, marking the largest City-sponsored neighborhood tree planting event of the season. These tree plantings aim to provide much-needed shade for homes while fostering community engagement, helping to mitigate heat stress and build stronger, more resilient neighborhoods. (1-5)

Masthuggsparken is a planned park in the Masthuggskajen district, which is undergoing development and construction. The park will measure about 2000 m2, and serve as a green oasis and meeting place for locals. It will have ameneties such as benches and areas for play, and a noise barrier against a large nearby road. The park will connect to the adjacent square and street, making it accessible to visit. The street will be renovated to have more trees and plants, increasing green connectivity in the district. The park will be surrounded by trees and other plants, which are planted to promote biodiversity and be adapted to a changing climate [Ref. 1-5, 7]. The park is at a low point, where up to 800 m3 of stormwater will flow during heavy rainfall, reducing flood risk in the surroundings [Ref. 1, 2, 6]. The Masthuggskajen district has a sustainability program, establishing goals for green environments which the park will contribute to. Green areas should be accessible to the entire district and provide ecosystem services such as rainwater management, climate adaptation, biodiversity and recreation. The program was created by the City of Gothenburg in collaboration with construction companies active in the area and was supported by Citylab Action, a national competence program in sustainable urban development [Ref. 7]. The City of Gothenburg is the primary responsible for the park, which will be constructed between 2025 and 2026 [Ref. 1, 2, 4].

The Tirana Vertical Forest is part of the city's 2030 Master Plan and aims to enhance urban biodiversity and create green spaces through innovative urban design (Ref. 1,2). The project was developed by Stefano Boeri Architetti, the same studio that has designed similar, well-known structures in cities like Milan, Utrecht and Nanjing (Ref. 6). The completion of the 21-floor building is expected in late 2024 and will feature 105 apartments and a commercial ground floor as well as 145 trees and over 3,200 shrubs and bushes which are integrated into the balconies and façade of the project (Ref. 1,2,3). Various Mediterranean plants have been incorporated, including colourful, scented and aromatic types, which harmonize with the local ecosystem. To maximise the space available for green features, a dynamic structure with alternating balconies and full-height windows has been built (Ref. 1,2). Ultimately, the project anticipates improving air quality, reducing noise, and providing insulation. The greenery is expected to capture fine particulate matter and up to 8 tones of Co2 per year while also creating a healthier microclimate for those inside the building (Ref. 1,6).

The "Tree Plantation Month" is an annual national initiative in Romania, organized by the Ministry of Environment, Water, and Forests through the National Directorate of Forests. This initiative focuses on afforestation, forest regeneration, and raising awareness about the ecological benefits of forests, while promoting sustainable behaviors (4, 9, 10). Having been in place for 60 years, the program has recently aligned with the principles outlined in the 1991 Paris Declaration on the Sustainable Development of Forests (10). At the national level, the initiative is regulated with overarching goals aimed at protecting and sustainably managing Romania's forests (9). The program allows for the involvement of various actors, including public institutions, municipalities, NGOs, and schools, who collaborate with regional forestry directorates to implement local activities (4).
In 2019, as part of this initiative in Iași, the Asociația Tineretul Ortodox Român Iași (ATOR), a youth-led religious association, actively participated in one of the campaigns . They planted 1,000 tree saplings in the Moara de Vânt district, an area that had suffered from deforestation and was prone to landslides (1, 2). The afforestation efforts were designed to address these environmental challenges by stabilizing the soil, reducing the risk of overflow and flooding, maintaining soil moisture, and regulating extreme temperatures (1). To ensure long-term success, the saplings were regularly monitored, and restoration efforts were carried out in cases where the trees were affected by fires or drought (3).

The Urban Oasis Playgrounds project focuses on creating a guide for green regeneration of playgrounds located all over Iasi by using natural climate solutions, with the potential for wider application beyond the city(1 to 6). The project's primary goal is to tackle pollution in playgrounds and address the overall lack of green spaces for children (1). This initiative is led by the NGO Civica in collaboration with the Municipality of Iași and the Architects Association in Iași (OAR) (1). The project secured €50,000 in funding after winning a competition organized by Raiffeisen Comunități, with support from the NGO "Asociația pentru Relații Comunitare" (2 & 3).
In addition to pollution, the project seeks to address other critical issues, such as the heat island effect and the proximity of playgrounds to risk-prone areas (1). The guide will be developed based on public consultations with Iași residents and a comprehensive study to tackle these concerns (1 to 7).
Currently, the first phase of the project is underway, involving assessments of various factors in playgrounds, including existing vegetation, shading, surface quality, infrastructure conditions, and pollution risks (4). These aspects are also reflected in a questionnaire distributed to the public, which gathers opinions on factors like cleanliness, noise exposure, thermal comfort, safety, and preferred natural green solutions (6).
The initiative aims to raise awareness about climate change, actively engaging the community in the process (4). Once completed, the guide will be presented to the municipality with the goal of being adopted as a standard for future playground developments (1, 3, 4, 6). The first phase of the project will regenerate a playground by planting trees and native vegetation (3).

The green belt regeneration project along the Byzantine Walls of Thessaloniki aims to revitalize the neglected green spaces surrounding these historic fortifications, which span 4 kilometers and are recognized as a UNESCO World Heritage site for their remarkable Byzantine architecture. The walls are located in Thessaloniki’s densely populated Upper Town, a factor that contributed to their environmental degradation. As such, the project focuses on restoring the degraded space surrounding the walls, improving the urban microclimate, and strengthening urban resilience while maintaining the area’s traditional character. By integrating heritage conservation with sustainable green infrastructure, the initiative seeks to provide both environmental and social benefits to the local community. Proposed by the Municipality of Thessaloniki and approved by the Greek government as part of a program that focuses on Central Macedonia, the project envisions a revitalized green zone along the walls, with vegetation and different types of trees being planted. However, some local families have expressed concerns, as the project involved the demolition of certain homes in the officially designated green belt area. (Refs. 1, 2, 3, 4, 14).

Phoenix is America’s fifth largest and hottest city, a sprawling urban heat island which has expanded without adequate consideration to climate and environmental factors like water scarcity and extreme heat (1). ​Multiple heat records were broken in 2023 including 133 days over 100F (37.7C), and 55 days topping 110F (43C) (1). Only around 9% of Phoenix is protected by tree canopies, yet this citywide figure masks vast inequities between wealthy, majority-white neighborhoods (1). As a response, the City of Phoenix has adopted an equity-driven heat mitigation plan to create a shadier, more livable environment amid rising temperatures and hundreds of heat-related deaths (1). Part of this plan created the Community Canopy Grant program, which offers public schools, churches and homes in qualifying census tracts – low-income neighborhoods with little shade funds for tree planting projects (1). One neighborhood, Grant Park is one of the city’s oldest neighborhoods – and one of the most neglected (1). It is a red lined neighborhood with higher pollution levels, less vegetation, more noise pollution and higher temperatures (1). To change the inequity and create enough shade to provide residents and passersby reprieve from the heat, the city planted around 40 trees in the Grant Park neighborhood within household yards (1-2). Residents can choose from a list of 19 native and desert-adapted trees including the Texas olive, Chinese red pistache and Chilean mesquites (1). The trees, which are a couple of years old and pretty heavy, are planted by contracted arborists (1). Following the planting process, each household was provided with a tree kit – a hose, irrigation timer and instrument to measure the soil pH and moisture, as well as written care instructions (1). This is the fourth tree planting effort by this city and the hope with this initiative is that it lasts (1).

‘Grün macht Schule’ has been informing, advising, and supporting schools and school initiatives in Berlin since 1983 in the planning and realization of schoolyard projects. The program focuses on improving school playgrounds by creating child-friendly, natural habitats and ecological learning spaces, making schoolyards better equipped to address climate change. In 2012, the program expanded with the launch of the ‘Grün macht Schule - KinderGARTEN’ funding initiative, which extended support to kindergartens.
Over the past four decades, with the program’s assistance, Berlin has seen the transformation of large, unstructured schoolyards into smaller, creative playgrounds. These spaces now feature imaginative and artistic objects alongside facilities for play, exercise, and communication. Additionally, many school gardens and biotopes have been established or restored, turning school grounds into vibrant ecological and educational environments .
The projects are largely driven by schools’ self-initiatives, with ‘Grün macht Schule’ offering support throughout. This grassroots approach fosters pride and a sense of ownership among school communities, strengthening their identification with the results. The collaborative effort also enriches educational practices, promoting inclusion, integration, and democratic participation. Such initiatives offer a hands-on experience with sustainable climate protection projects, making these efforts tangible and impactful in everyday school life.
In addition to its project-based support, ‘Grün macht Schule’ provides training for school teams, organizes regional and national conferences, and hosts seminars and lectures to share best practices and inspire further action .
The program is a cooperative effort between the Senate Department for Education, Youth and Family and the association Freilandlabor Britz e.V., operating under the guidance of the Senate Department. (Ref. 1-4, 6)

As heat waves and high temperatures intensify due to climate change and urbanization, the City of Phoenix is exploring how to reintroduce tree shade into urban spaces to create a more equitable, livable environment. In 2014, the city set a goal to shade at least 25% of Phoenix by 2030, known as the Tree and Shade Master Plan. Achieving this ambitious target requires substantial resources and active community participation.
A key player in this initiative is Trees Matter, an environmental nonprofit dedicated to helping Phoenix reach its shade goals. Trees Matter not only works to expand and sustain the city’s tree canopy but also aims to foster environmental equity. Among its initiatives, the Trees for Schools program promotes tree planting in schools while educating staff and students about the significance of trees and tree care.
Silvestre Herrera Elementary School is one example where the Trees for Schools program has made a direct impact. As part of this program, 30 trees were planted on the school grounds, involving students, staff, and community volunteers in the process. These new trees offer critical environmental benefits, including shade, air purification, dust reduction, food production, and carbon sequestration. Additionally, tree presence has been linked to improved physical and mental health outcomes.
Beyond the immediate environmental gains, the project also offers educational value by involving students, staff, and maintenance crews in hands-on learning about tree care and environmental stewardship. This approach ensures that participants are equipped with the knowledge and skills needed to care for the trees long term, reinforcing both sustainability and community resilience.
Through these combined efforts, Phoenix is making strides toward a greener, more shaded future—one that benefits not only the environment but also the well-being and health of its residents. (1-5)