Lowered local temperature

Bound by miles of steel, concrete, or brick walls, Berlin’s rivers and artificial canals often look alike. Plastic bottles, along with ducks, swans, and perhaps the occasional coot seeking scraps from humans, are some of the few visible signs of life. Underwater, the scene is similarly sparse and monotonous, with only a handful of resilient species able to endure the harsh conditions.
In response to this lack of biodiversity, researchers from the Leibniz Institute for Freshwater Ecology and Inland Fisheries in Berlin collaborated with the engineering firm Wite to create the Vertical Wetland project. This initiative introduced plant boxes that attach to sheet piling along canal walls, extending into the water to form miniature habitats. These boxes serve as refuges for insects, birds, fish, and other small animals, offering hiding spots and sheltered spaces for egg-laying among the roots and boxes protruding into the water. Known as "ecological stepping stones," vertical wetlands enable animals to rest and safely traverse urban waterways, fostering biodiversity along urban riverbanks.
Vertical wetlands present a quick and cost-effective way to ecologically upgrade sections of urban waterways. Although they can’t fully replace natural riverside habitats, these mini-habitats offer substantial ecological benefits. Native river floodplain plants, including willows, reeds, rushes, and shallow-water species like irises and marsh marigolds, provide the foundation of these structures. All materials used are environmentally friendly and biodegradable.
By covering the grey, industrial surfaces of riversides, the vegetation cools the local environment, both on land and in the water, and helps improve water quality. Plant shading cools water, reducing eutrophication risks and creating a healthier habitat for aquatic life.
The Vertical Wetland project’s pilot installation was successfully implemented and tested in 2023 in the Berlin-Spandau Ship Canal. (1, 3, 6)

The Detroit RiverWalk is an urban development project along the Detroit River, designed to reconnect residents with their waterfront and revitalize a historically industrial area. Once characterized by abandoned buildings and industrial debris, the riverfront between the MacArthur and Ambassador Bridges had long been inaccessible to the public. To address this, the Detroit Riverfront Conservancy was established in 2003 to lead the redevelopment of this space.
The RiverWalk currently stretches along a 3.5-mile section, with plans to expand to 5.5 miles, integrating ecological restoration, public access, and recreational opportunities. The esplanade features native landscaping, artistic elements, and amenities, including four pavilions, a custom carousel, and areas for fishing, walking, biking, and inline skating.
Environmental remediation has been a crucial part of the project. In collaboration with the U.S. Environmental Protection Agency’s Great Lakes National Program Office, the Detroit Riverfront Conservancy successfully cleaned up 13,000 cubic yards of contaminated sediment, significantly reducing pollution and contributing to the removal of the Detroit River from the list of the most polluted sites in the Great Lakes. Furthermore, the project also includes greenways, park creation and revitalization.
The RiverWalk is not just a public space; it symbolizes Detroit’s transformation from a Rust Belt city to a sustainable urban environment. It exemplifies the power of public-private partnerships in revitalizing urban areas. The RiverWalk continues to expand, with plans to connect various parks and extend to the Ambassador Bridge, further enhancing the city’s waterfront. Its success was recognized in 2021 when it was named the Best Riverwalk in America by USA Today, cementing its status as a model for urban renewal and community engagement. (Ref. 1, 2, 3, 4)

In 2021, the real estate company Inamstro, in collaboration with the Municipality of Iași, the civil organization "Glasul Vieții" (Voice of Life), and local citizens, initiated a tree-planting initiative that involved planting 250 trees near a residential area and a parking lot in the Frumoasa neighborhood of Iași. This neighborhood is smaller compared to other areas of the city and was developed during the communist systematization of the 1970s and 1980s. It consists of groups of four-story blocks arranged around common spaces, situated near the Frumoasa Monastery complex.
The main goals of the 2021 planting action were to enhance green space, lower air temperatures, reduce urban air pollutants—such as fine particulate matter—absorb CO2, and improve overall health and quality of life (1–5). Additionally, the implementing company concluded that the trees planted near residential areas can significantly reduce energy needs for air conditioning and heating, leading to an average cost decrease of 30% during summer and winter (1, 2).
Volunteers participating in the project received a "tree certificate," signifying their commitment to planting and adopting a tree (7). In this initiative, volunteers were also tasked with monitoring the growth of their adopted trees to ensure their health (1–6).

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).

Civic Space Park, located in the heart of Phoenix, Arizona, is a notable example of urban design aimed at addressing the region’s increasing urban heat. In Phoenix, rising temperatures affect health, safety, comfort, and economic growth, and this impact is expected to worsen over time. In response, the park was developed to transform an underused site into a vibrant public space that prioritizes community engagement, sustainability, and urban revitalization.
The project was realized through a public-private partnership between the City of Phoenix and Arizona State University, with strong community involvement shaping its development. This collaboration led to the “Urban Weave” concept, a design that embodies the identity and values of the local community.
Civic Space Park was designed with several goals in mind. Increasing the tree canopy was essential to help reduce the urban heat island effect and improve air quality. Creating a welcoming area for social interaction, recreation, and relaxation was equally important to enhance community well-being. Water conservation was also prioritized, achieved through innovative stormwater management techniques such as permeable paving and underground infiltration. The park incorporates renewable energy generation as well, with on-site solar power helping to reduce energy consumption.
One of the park’s unique features is its extensive use of pervious concrete paving, designed to allow stormwater to permeate directly into the subsurface. However, during installation, it became clear that placing the material over highly compacted soil limited water infiltration. To improve its effectiveness, future designs could include a plastic vapor barrier beneath the permeable paving to capture water and direct it to planting beds. This adjustment would enable the paving to act as a collection and storage system, gradually releasing water into the surrounding vegetation.
(1-6)

As an industrial city under climate change, Birmingham has been confronted with multiple environmental risks such as air pollution, fluctuating precipitation and flooding (Ref 3). The Big City Plan is a 20-year city center regeneration plan to support Birmingham’s sustainable transformation, where the delivery of the Eastside City Park was prioritized (Ref 1, 2). Completed and opened to public in 2013, this first new park in Birmingham for 130 years is a linear site which connects the city center along the frontage of Millennium Point eastwards towards the Digbeth canal. (Ref 1, 4, 5). Providing 2.73 ha of urban green spaces, the multi-award winning development features more than 300 trees, a 110 meter canal water feature and a public square with 21 jet fountains, and offers “a moment of green in a journey through the city” (Ref 1, 6).

The project features a vertical garden, or "living wall," on the facade of a residential building in Berlin’s Kreuzberg district. Constructed in 2016, the building replaced a WWII-damaged plot situated between two existing structures. With a strong emphasis on sustainability, the project minimizes its ecological footprint in various ways. The 660-square-meter plot retained original elements of the location’s history: the two surviving sections along Glogauer and Reichenberger Strasse were restored after the war, while the rubble from the destroyed corner was used to fill in the basement. This approach allowed the new construction to be built over the original foundations, preserving historical integrity while reducing construction costs and material use.
At the core of the building’s design is a green agenda, embodied in the vertical garden that helps absorb noise and pollution from the bustling street below, improving air quality for residents and passersby. The selection of winter-hardy plants ensures that the facade remains green year-round, while also cooling the surrounding area and mitigating the urban heat effect, which is especially valuable in densely populated neighborhoods. The greenery contributes to the local microclimate, providing both environmental and aesthetic benefits.
For residents, the garden is made accessible through rectangular box balconies that project from the green wall, allowing them to engage closely with the plants and enjoy the immersive garden atmosphere. The plants grow on a support structure that is securely anchored in the brickwork, receiving water and nutrients through an integrated, precision-controlled irrigation and fertilization system. Maintenance of the plants occurs twice a year, with new additions planted each spring to maintain the garden’s health and visual appeal.
The building itself, privately owned, contains a mix of holiday rentals and residential apartments. Architect Sarah Revière designed the project. (1-6)

Ireland’s native trees have developed over thousands of years, forming a vibrant ecosystem alongside surrounding plants, animals, fungi, and microbes. These trees provide critical habitats for plants and wildlife, offering essential food and shelter while producing oxygen vital to animals and humans alike. Historically, native trees supplied early Irish communities with fuel, food, shelter, and building materials. Today, they play a modern role in filtering dust, reducing pollution, and enriching urban spaces.
To highlight these benefits in Dublin, the Native Tree Trail in St. Anne's Park was created by DCC Parks and Landscape Services in 2008. This trail, featuring 15 different types of native trees, invites visitors to explore and appreciate the natural and cultural heritage of Ireland's native trees, underscoring the value of green spaces for both biodiversity and community well-being.
Strategic tree placement contributes to Dublin’s sustainability by reducing soil erosion, sequestering carbon, and mitigating urban heat. A green city is a healthy city, and preserving open spaces enhances its appeal as a place to live, work, and visit. The trail also plays an essential role in environmental education and community engagement. Over the years, St. Anne's Park has hosted multiple tree-planting events, including a 2019 collaboration with local schools for National Tree Week and National Tree Day, in partnership with the Tree Council of Ireland. The NGO has also offered family-friendly guided walks along the trail, helping to instill an appreciation for nature in visitors of all ages (1, 2, 3, 4, 5, p.93).

The Cinturón Verde de Independencia initiative is a pilot intervention that seeks to plant an urban forest in the lower middle-class district of Independencia (1) in the northern part of the urban territory (3). Here, 19% of the population lives in high-risk conditions, settled on steep slopes, and threatened by landslides (3).
It is part of a broader planning strategy that involves proposals engaging different levels of government (4). This project seeks to afforest the district's hillsides to improve the environment, reduce air pollution, improve the quality of life of its inhabitants, manage waste, regulate shade, control erosion, increase wild biodiversity, and provide spaces for environmental education (2). The Independence Green Belt is linked to a wide range of plans, projects, and decrees that have been developed by actors at different levels of government since 2016 (4). It works hand in hand with the EBA Lomas programme and seeks to create a green belt along the Lomas-city interface, which acts as a buffer zone for this sensitive ecosystem and creates a protective boundary against the expansion of irregular human settlements while providing a space for environmental awareness (2).
This program was developed by a consortium of multiple private, public, national, and international parties with strong community support (3). In two phases, an urban forest park of 4,800 of native trees irrigated with treated wastewater has been planted. During the first phase, PREDES planted 3,300 trees with USAID support in 2015, and another 1,500 were recently planted by PERIFERIA (consultants) (3).
The Independencia Green Belt occupies the hill areas of the district of the same name and relates to a possible metropolitan-scale buffer belt.
Its boundaries take advantage of the seven Sustainable Ecotourism Forest Parks (PFES) in the District Municipality of Independencia (MDI), as well as 115 hectares of the Amancaes Lomas (4). It aims to conserve 400 hectares (4).

The Heat Action Planning project in the Lindo Park-Roesley Park Neighborhood in Phoenix, Arizona, specifically addresses the heat-related challenges residents face in this area. Phoenix is particularly vulnerable to extreme heat events, and this project aims to provide both mitigation and adaptation strategies to reduce the direct impacts of heat and help residents cope more effectively with these conditions. As part of the city’s broader Heat Action Plan, the Lindo Park-Roesley Park initiative is one of three target areas, including Edison-Eastlake, just east of downtown Phoenix, and the Water Tower Improvement District in the City of Mesa. The project focuses on heat hazards such as extreme temperature events and the urban heat island effect, which disproportionately affect vulnerable populations.
This project is a collaborative effort, uniting a range of stakeholders including The Nature Conservancy, Maricopa County Department of Public Health, the Central Arizona Conservation Alliance, the Urban Resilience to Extremes Sustainability Research Network, Arizona State University’s Urban Climate Research Center, and the local residents. Together, these partners are working to develop comprehensive heat mitigation and adaptation strategies that address social equity and strengthen community engagement. Furthermore, the Heat Action Planning process was designed to serve as a model for future heat resilience efforts and create a local, contextual, and culturally appropriate vision of a safer, healthier future. The iterative planning and engagement method used by the project team strengthened relationships within and between
neighborhoods, community-based organizations, decision-makers, and the core team, and it combined storytelling wisdom and scientific evidence to better understand current and future challenges residents face during extreme heat events.The ultimate aim is to foster a more resilient and equitable neighborhood (1-7).