City specific climate change policy or plan

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).

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)

The regreening project is located in Seestadt Aspern, a newly developed urban area in Vienna's Donaustadt district. Two years after the completion of buildings, streets, and squares, the ground was reopened in 2022 to address the challenges posed by urban heat islands. Pavement was removed, and trees and shrubs were planted to provide shade, create insect habitats, and open seepage areas for rainwater. Additional features like benches, a water station, and water jets were installed to enhance the area's livability. These measures improve the overall quality of life, offering residents green spaces to relax and opportunities to cool down through water play.
The project spans three connecting squares in Seestadt: Wangari Maathai Square, Simone de Beauvoir Square, and Eva Maria Mazzucco Square. In 2022, Wangari-Maathai-Platz and Simone-de-Beauvoir-Platz underwent intensive regreening. By 2023, Eva-Maria-Mazzucco-Platz in the Seeparkquartier was similarly transformed with additional greenery and cooling features. Under the slogan "Out of the Asphalt," one of Europe's largest and most innovative urban development projects took a significant step toward improving quality of life.
In 2023, over 1,100 square meters of asphalt were removed and greened. This effort included the creation of 12 new green beds planted with grasses, perennials, and shrubs. The design also introduced two square-like recreation areas with existing seating elements surrounded by green beds, providing shaded, pleasant spaces for relaxation.
The Eva-Maria-Mazzucco square was designed by a local NGO specializing in citizen engagement in urban development, while the project's overall initiation and implementation were led by the City of Vienna, the Donaustadt district, and Wien 3420 Aspern Development AG. This collaborative effort demonstrates how regreening initiatives can mitigate heat islands, foster urban biodiversity, and create more attractive, livable spaces. (Ref. 1-3)

The "Plan Arbre" is a tool for ecological planning and renaturation aiming to plant 308,000 trees between 2023 and 2029, sourced from the municipal nursery with seeds purchased from local suppliers (Ref 1, Ref 2). In 2023, 14,922 trees were planted, with plans to double this number in 2024 (Ref 1). The project addresses the loss of 50% of Marseille's natural spaces over the past 75 years, aiming to reverse this trend and reintroduce nature into the urban environment (Ref 2). It also tackles issues like drought and heatwaves, particularly in summer, by using trees and shrubs to cool the air, restore biodiversity, reduce air pollution, and enhance public spaces while absorbing CO2 (Ref 2).

The plan is divided into two phases. Phase I focuses on planting in Marseille's 58 parks and 273 squares and gardens, as well as around childcare centres, schools, socio-cultural centres, and sports facilities (Ref 2, Ref 3). From 2020 to 2023, various improvements were made, including playground renovations, installation of misting systems, automatic watering, and the creation of a CrossFit area (Ref 3). Phase II will involve identifying major boulevards, avenues, and streets lacking trees to enhance the urban canopy (Ref 2).
A diverse range of tree species were selected for their drought resistance, water efficiency, and ability to attract biodiversity (Ref 2, Ref 3). The project also focuses on increasing biodiversity and managing invasive species through natural methods to protect trees from pests without chemicals (Ref 3). Furthermore, the initiative includes de-impermeabilizing soils and implementing a smart irrigation system with tensiometric sensors, developed with the start-up GreenCityZen, which has saved 66% of water in two years (Ref 3). The Plan Arbre also promotes citizen participation, with 23 parks selected for community gardening projects, where ten winning associations will receive plants from the municipal nursery (Ref 1).

The city of Thessaloniki is tackling the energy crisis and climate change risks by prioritizing the installation of green roofs and green walls on school and municipal buildings as part of its resilience strategy, Thessaloniki 2030 (Ref 1, 2). One key project under this strategy has been implemented at EPAL Stavroupoli, one of the largest school complexes in the metropolitan area. The school, with a total built area of 11,918 sq.m and roof surfaces covering 6,042 sq.m, now includes a green roof covering 3,087 sq.m with 25,000 ground-cover plants, along with a vertical garden on three walls at the entrance, covering 100 sq.m and featuring 3,098 plants (ibid.).
The project is expected to yield multiple environmental benefits, such as reduced energy losses, improved thermal performance, enhanced sound insulation, better rainwater management, decreased runoff, and retention of harmful particles, all of which contribute to upgrading the area's green infrastructure (Ref 1). This initiative also strengthens the green fabric of western Thessaloniki and improves the local microclimate while addressing rainwater management issues (Ref 3, 4).

Minimizing heat stress is a critical priority for Phoenix, the hottest major city in the U.S., where heat-related deaths reached at least 359 across Maricopa County last year. The city's expansive urban layout and infrastructure exacerbate the urban heat island effect, making an already scorching climate even more hazardous. In addition, heat impacts communities unequally, with some neighborhoods up to 10 degrees hotter than others. Lower-income and predominantly Hispanic neighborhoods often have less canopy cover and fewer resources to combat rising temperatures, making them more vulnerable to extreme heat.
To address this, the City of Phoenix launched the Cool Corridors Program in 2020, a key initiative in its broader climate resilience strategy. This program, a partnership with American Forests and the Phoenix Street Transportation Department, aims to establish a network of shaded pathways that connect communities across the city. These corridors enable residents to travel safely to schools, public transit, and other city hubs, promoting environmental sustainability and public health.
The program prioritizes investment in low-income, heat-sensitive neighborhoods to improve tree equity and create green spaces where they’re most needed. The first Cool Corridor was developed in 2022 at Cesar Chavez Park, where over 250 trees were planted with the support of more than 100 volunteers, setting a strong example for future initiatives. By 2030, Phoenix plans to complete 100 Cool Corridors citywide, building a more resilient and livable urban environment for all residents. (1-5, 7-8, 10)

Over the past 10 years, Lima's population has grown from 8.2 to 9.6 million people. As the city's urban sprawl and population density have increased, green spaces have been replaced by grey infrastructure. Consequently, it has become challenging to ensure that residents enjoy a good quality of life (1, 2, 3). In December 2019, Lima City Hall launched "Limeños al Bicentenario," an initiative to revitalise the city's public spaces (1, 3). This program seeks to transform public areas through low-cost interventions, based on criteria such as vulnerability, citizen participation, and catalytic potential, among others (3). It also aims to foster social cohesion by involving residents in the maintenance of these newly renovated areas, while improving the city's resilience to climate change (1, 2, 3). Since its inception, the project has reclaimed 17 public spaces, covering an area of 41,000 m² (3). 430 trees have been planted, and the project has benefited from the collaboration of civil society and private sector partners (3). The programme also focuses on addressing climate change. Heat waves, droughts, floods and mass migration are the main climate-related risks affecting the city. In particular, the expansion of grey infrastructure at the expense of green spaces has exacerbated the risk of heat waves, causing temperatures to rise by up to 3.5 °C in certain areas of Lima (3).
One of the projects involved the recovery of public spaces in Teniente Pavia. For many years, the space was used as a public parking lot, and at night it accumulated garbage, there was alcohol consumption, drug use, and other problematic issues. There was no vegetation, benches or infrastructure for recreation. The neighbours, especially children, did not have access to green areas or recreational spaces (5). For this reason, in 2020 the project was initiated to repair sidewalks, plant vegetation, create gardens, and install infrastructure for play, rest, and exercise (3, 4).

Phoenix is one of the hottest cities in the United States, with temperatures regularly exceeding 40°C (104°F) for more than 90 days each year. The urban heat island effect is severe here, posing a significant health risk. Many communities in Phoenix lack equal access to shade cover—often, the impact of extreme heat disproportionately affects low-income neighborhoods that lack resources for tree planting and maintenance. In contrast, wealthier areas tend to have more trees and are visibly greener, which helps reduce the heat residents experience.
To address these disparities, the City of Phoenix partnered with SRP, a not-for-profit public power utility, to launch the "Right Tree, Right Place" program in 2018. This initiative aims to bring shade relief to areas most in need, such as parks, public transit stops, and schools, while replacing older trees that interfere with SRP power lines. SRP and the city work together to identify trees that pose risks to overhead power lines, and for each tree removed, three new trees are planted—either in a different location or with a species better suited to coexist with power lines.
One of the program’s notable projects took place in West Phoenix’s Cortez Park, where 24 drought-tolerant trees from four different species were planted. This diversity helps protect the trees against pests and other natural threats, ensuring their longevity and resilience. Through initiatives like these, the "Right Tree, Right Place" program contributes to Phoenix’s larger goal of developing a robust, biodiverse urban forest. By expanding green infrastructure, the city aims to reduce local temperatures, improve air quality, and create cooler, healthier neighborhoods for all residents. (1-8)

Two new wetlands were established in Dodder Valley Park as part of the Dublin Urban Rivers Life Project (DURL). This project aimed to create integrated constructed wetlands (ICWs) at strategic locations in South Dublin County to purify wastewater and storm-water before it discharged into rivers.
The ICWs consisted of a series of cells resembling shallow ponds, typically 200 to 300 mm deep. Heavily planted with specific vegetation, these cells treated water by removing nutrients and harmful impurities, resulting in cleaner, purer water being discharged. The water flowing into the wetlands came from wastewater of misconnected appliances and storm-water pipes located under public roads, which collected rainwater from roads, footpaths, and the roofs and patios of houses.
These wetlands also provided important benefits, including flood alleviation, bioretention of particulates and nutrients, improved habitat conditions, and enhanced biodiversity. The project aimed to promote the relationship between green infrastructure and public well-being, creating a complex biological system that supports a diverse range of plants, animals, microorganisms, and hopefully attracts frogs, newts, and birds.
To increase native biodiversity, the wetlands were designed with pollinator-friendly plants and trees, making them visually appealing for park users and the public. A Wetland Planting Day took place on September 9, 2022, with over 40 participants, including residents and representatives from local organizations. This phase of the project fulfilled not only the objectives of the LIFE project but also those of the River Basin Masin Management Plan 2022–2027, the Water Framework Directive, the Climate Change Action Plan, the Floods Directive. (1, 2, 5)

San Borja has 1,347,000 square metres of green areas, equivalent to 12 square metres of green space per inhabitant, one of the highest ratios in the capital (1, 2). In total, there are 75 parks within its jurisdiction (1, 3). However, in recent years it has consolidated its role as a metropolitan urban centre and has become denser with new multi-family construction projects replacing traditional single-family homes with gardens (2). As a result, tree cover has decreased, affecting the creation of shaded areas and air quality, putting the health of residents at risk (2). Nevertheless, this municipality has reaffirmed its participation in the Global Covenant of Mayors for Climate and Energy, committing to implement policies and take measures to reduce (or limit where appropriate) greenhouse gas emissions and prepare for the impacts of climate change, as it is vulnerable to heat waves and droughts, as well as high wind and thunderstorm hazards and fires (1). Thus, since 2014, 56,000 trees have been planted, which is one tree for every two residents in the district (2). The mitigation programme includes 40 measures, including the creation and conservation of green areas, which involve planting trees to create urban forests to help regulate temperature, prevent heat waves, improve CO2 absorption, and preserve endemic species (1). In addition, the programme promotes the use of organic farming practices and the propagation of plants using natural methods (1).
One of the sectors where there has been the most progress is Sector 12, with 31% of the green areas created (3). Within this sector, the district is planting and creating an urban forest within the premises of the Army Headquarters, better known as ‘Pentagonito’. Its objective is to educate neighbours and promote greater environmental awareness (3, 4, 5).