Increased green space area

Lisbon is facing an increasing threat linked to climate change due to its geographical location and climate (6), which has had a negative impact on health and quality of life in the city (5). Its average annual precipitation is decreasing, although the city experiences more winter precipitation. This results in longer droughts and more seasonal flooding, which reduces water retention and soil conservation (6). Average temperatures are increasing by 14°C per year, with maximum temperatures up to 5°C higher (6).
As an adaptation measure to these challenges, the LIFE LUNGS project aims to increase Lisbon's resilience by implementing green infrastructure and promoting related ecosystem services (1, 3, 5, 6). Thus, it focuses on measures aimed at coping with temperature increase, mitigating the effects of heat waves and water scarcity, which are expected to become more frequent, being in line with the climate policies adopted by the municipality. The project runs from 2019/2020 to 2024/2025 (1, 5, 6). It aims to address cross-cutting issues such as climate, water and biodiversity (3). The project expects to work hand in hand with the City of Malaga, which has been developing projects aimed at adapting the city to climate change. It is expected to replicate the work in Malaga and post-project to 2 national territories, and 1 in the EU (4). It is also intended to transfer the project work to be implemented in private areas that are part of Lisbon's green infrastructure, and to disseminate and technically train municipalities of the Lisbon Metropolitan Area and other municipalities committed to climate change adaptation (4).

Public spaces in Colombo are disappearing due to rising land prices, causing infrastructure issues that harm citizens' health, especially in low-income areas (3). One proposed solution to address the problems caused by rapid urbanization is the creation of community gardens, which can at least improve low-income residents' diets and immune systems and address malnutrition (3).
Considering the limited urban space for both citizens and other living beings, the organization Eco-friendly Volunteers decided to create a community garden. The Metta Garden in Colombo (1, 2) aims to bring back urban biodiversity through organic home gardening, generating healthy food for people and creating living space for many other animals and plants (2). Following the Buddhist concept of Metta (loving-kindness to all beings), it promotes walking meditation paths and facilities to experience nature using all five sensory organs (1), in addition to being a place for experiencing loving-kindness for both human and non-human living beings, seen and unseen (4, 5).
It has become a training institute for many stakeholders seeking to grow organic food and earn a better income through the high demand for organic products (2). At the same time, it serves as a biodiversity spot, attracting butterflies, bees, and other forms of wildlife to an urban environment (2).
The area is located in the middle of a semi-urbanized area, on the outskirts of Boralesgamuwa (2, 3). Maintained by a group of volunteers, it features a greenhouse and a plot of land of around 5,000 sq feet, populated with vegetable patches, a butterfly garden, flowers and rare medicinal plants (3, 4). The garden was divided into four sections representing the Buddhist elements: water, heat, air, and solid. Each section features specific plants and designs, like a pond for water, a compost pit for heat, tall plants for air, and a rock garden for solid. The layout follows a mandala design based on permaculture principles (4).

Sri Lanka, particularly its low-lying coastal areas, faces recurring flooding challenges exacerbated by climate change, coastal erosion, and urbanization (1). Wetlands have emerged as crucial ecosystems in mitigating these risks, acting as natural sponges during heavy rainfall and releasing water gradually as flood levels subside (1). Beyond flood control, wetlands play a vital role in environmental quality. Their biodiversity helps filter pollutants and chemicals from the air and water, creating a healthier environment for both humans and wildlife (1). In 2018, Colombo was designated as a Global Wetland City under the Ramsar Convention, becoming the first and only capital city to receive this recognition (1). Recognizing the significance of wetlands as nature-based solutions, international institutions have prioritized their conservation through financing programs (1), and the city has developed projects to raise awareness and involve its citizens in their protection (1). These efforts have resulted in the creation of four wetland parks in the city, that comparing to a wetland, the wetland parks have more human intervention. Thus, they are focused on different topics and activities (2): Diyasaru Park, Beddagana Wetland Park (managed by the Urban Development Authority), Kotte Rampart Wetland Park (managed by the Urban Development Authority), and the Gothatuwa Wetland Park (managed by the Sri Lanka Land Development Corporation) (2). Gothatuwa Park is the newest wetland park and it is located in the flood-prone Gothatuwa neighbourhood (1). Inaugurated in 2024, It has a recreational focus, with trails for cyclists and hikers, and together with the other wetland complex, this park is designed to make the wetlands a cornerstone of local people's lives (1). Currently, environmental education activities are carried out in the park, focusing on managing aquatic invasive plants, tree planting and solid waste collection (3).

The Thalangama wetlands are part of a network of wetland ecosystems around Colombo city that spread over 20 km2 and provide critical life support to the city. These ecosystems keep people safe from floods, cool the air, filter polluted water, provide food and medicines, and fight climate change (10). These wetlands have become an environmental protection area and a biodiversity hotspot in a rapidly urbanising environment, as they host an array of plants and animals, including the endangered fishing cat and otter (5, 10). In 2007, Thalangama Lake and its surroundings were declared an Environmental Protection Area (EPA) under the National Environmental Act (4, 5). This protected area covers approximately 118 hectares (4) and includes two man-made reservoirs: Thalangama Tank (11 ha) and Averihena Tank (3.2 ha), located just 300 meters apart (5). The area hosts floating and rooted plants, scrublands, and trees that provide habitat to up to 100 species of migratory, resident, and endemic birds throughout the year. In addition, the area supports 30 species of dragonflies, 12 species of reptiles, 10 species of mammals, and 15 species of freshwater fish (1, 4). Since the lakes and their surroundings were declared an EPA, only limited uses are permitted, such as traditional fishing and rice cultivation (4, 5). The lakes are also important for floodwater retention and have high scenic and aesthetic value, attracting many visitors, and scientific and educational activities (5, 13).
However, due to the area's rapid urbanisation, land values have increased significantly, leading to excessive landfilling and the reclamation of paddy lands for housing. This is compounded by the indiscriminate disposal of garbage and construction waste and the spread of invasive species (5). These challenges have also led to the engagement of surrounding communities in managing and maintaining it (11).

In 2018, the City of Detroit implemented a drainage charge to help cover the costs of capturing, conveying, pumping, treating, and safely returning combined sewage to the Detroit and Rouge Rivers (1). The charge is calculated based on each parcel’s impact on the sewer system, particularly by measuring impervious acreage (1). Since then, this fee has posed significant challenges for one group in particular: Detroit’s houses of worship (2). Churches, with their large roofs and parking lots, face higher monthly drainage charges, creating financial strain for many faith leaders (2).
To support these institutions, Sacred Grounds has been providing grants, labor, and design assistance to install projects that reduce water bills and drainage fees (2). Sacred Grounds collaborates with the National Wildlife Federation, Friends of the Rouge, and Sierra Club of Michigan to implement these projects through the city’s green credit program (2). A recent initiative involved installing four rain gardens located on the perimeter of St. Suzanne Our Lady Gate of Heaven Church (3). These bioretention gardens, funded by several private and public actors and led by Detroit Future City, diverts water from 20 large downspouts, redirecting an estimated 500,000 gallons of runoff annually away from the municipal sewer system (3, 4).
In addition to managing water, the gardens foster a thriving habitat for pollinators and adds beauty to the area (3). St. Suzanne’s commitment to environmental education includes engaging over 130 youth and adults in training programs that build pathways to STEAM careers and opportunities where local residents are often underrepresented (4). The church also features an innovative, eco-friendly outdoor classroom developed by students, further supporting their sustainability mission (4).

The environmental impact of golf has led to growing calls to make the sport more sustainable (1). Golf course maintenance often involves carbon-intensive fertilizers, frequent mowing, and, in some cases, the clearing of forests or trees that naturally absorb carbon dioxide to make room for expansive fairways (1). However, the Tournament Players Club (TPC) Michigan is working to create courses that benefit both golfers and the environment (2).
Fifteen years ago, the site was a neglected floodplain along the Rouge River, initially purchased by Henry Ford in 1915 and once littered with community waste and old motor parts from the Ford Motor Company (2-3). Today, it has been transformed into an 85.8-hectare course that supports a diverse range of wildlife, including birds, fish, foxes, and coyotes (2). Led by Jack Nicklaus, the restoration aimed to turn this former waste site into an eco-friendly course (2). With guidance from Audubon International, the course was converted into a wildlife sanctuary, becoming the world’s first golf course to receive the prestigious John James Audubon Environmental Steward Award for ecological restoration (2).
TPC Michigan features native Michigan plants, such as viburnums, which produce berries for wildlife, along with various native grasses (2). To prioritize environmental stewardship, the course managers have created buffer zones to protect natural habitats and conserve water by using coring methods to monitor soil moisture (2). Pesticide use is minimized; instead, staff monitor for signs of disease or pests and test the soil to determine the specific nutrients needed for the turf (2). The course’s links-style layout includes rolling fairways, tiered greens, and natural wetlands, with tee options ranging from 5.5 to 6.4 meters (4). By establishing a wildlife sanctuary, TPC Michigan offers golfers a unique experience that fosters a connection with nature (3).

The stretch of the Great Lakes basin ecosystem from southern Lake Huron through western Lake Erie forms a unique urban refuge where life thrives with beauty and resilience. Known as Metropolitan Detroit, this region is where the Community Foundation for Southeast Michigan and many partners are working to create The Great Lakes Way by connecting 160 miles of greenways and 156 miles of water trails (1).
The vision for the Great Lakes Way project is to ensure that all residents and visitors of southeast Michigan—people of all ages, backgrounds, ethnicities, abilities, and interests—feel connected to the water resources, welcomed on its trails, and able to enjoy the benefits and opportunities these access points provide (1). To bring this vision to life, the project plans to link 160 miles of greenways and 156 miles of blueways, connecting people to a range of world-class freshwater, wildlife, and recreational opportunities. These include fishing areas, bird migration pathways, parks, working waterways, preserved woodlands, and restored wetlands (2).
The Great Lakes Way project connects existing assets, supports accessibility and equity, and promotes the Great Lakes Way to both residents and visitors through marketing and communication efforts (2). There are 26 points of interest that will serve as connection hubs along the Great Lakes Way (2). In Detroit specifically, the focus is on connecting 13 culturally or historically significant destinations, as well as locations known for their environmental and ecological importance or as regional landmarks (2).
Rich in world-class fisheries, migratory flyways, parks, urban centers, small towns, preserved old-growth woodlands, and restored wetlands, the Great Lakes Way offers unique experiences that can only be found here. By uniting the natural and cultural assets the Great Lakes Way designation aims to emphasize and expand the essential linkages needed to further connect this remarkable region. (2,3)

Sri Lanka faces multiple natural hazards, including tropical storms, flash floods, and landslides. As the country's urban population has grown, development projects have encroached on wetlands, compromising their natural flood protection, air and water purification, and carbon storage capabilities. Additionally, hilly regions are at risk of landslides, particularly during the monsoon season, posing significant threats to vulnerable communities (4).
To address these challenges, the World Bank and the Sri Lankan government collaborated on the Metro Colombo Urban Development Project. This initiative focused on nature-based solutions (NBS) as cost-effective and sustainable approaches to risk management (4). By strengthening natural processes and ecosystem services, the project aimed to mitigate hazards such as floods, erosion, and landslides (4). Technical assessments by the World Bank highlighted the importance of wetlands in flood protection, leading to efforts to protect and restore 20 square kilometres of freshwater lakes, wetlands, and swamps (1, 4).
The project supported the Sri Lankan government in reducing flooding in the Colombo Water Basin and enhanced local authorities' capacity to manage infrastructure and services. It prioritised metropolitan investments to mitigate the physical and socioeconomic impacts of flooding and aimed to build long-term capacity for urban management and local service delivery (6).

To reduce the risk of urban flooding, the city of Seville, through its metropolitan water company Emasesa, established several "sustainable urban drainage systems". One of the pilot locations is on the Avenida de las Ascociaciones de Vecinos, where a rain garden complemented by an infiltration zone was established. The main aim of the project is to reduce the risk of flooding, but the system can also improve the urban landscape by offering green space, preventing desertification and reducing pollutants carried by runoff [Ref. 1-4]. After implementation, the project was shown to be effective during heavy rain [Ref. 5]. The system can store up to 34 m2 of water and reduce flow rates to the sewage network by 69 % and the total runoff to sewage by 93 % [Ref. 3-5]. The project was initiated and led by Emamesa, while two different companies were employed to design and construct the system [Ref. 1, 2, 6, 7]. The total budget of the project, which also included some renovations of grey infrastructure along the street, was 165000 EUR [Ref. 1].

In May 2020, CityLAB Berlin launched "Gieß den Kiez", an interactive platform designed to support Berlin's urban trees by fostering collaboration between citizens and the city. The platform enables voluntary civil society efforts to help water the city's endangered tree population. It features a map that visualizes nearly all of Berlin's street and park trees, complete with data such as water requirements, age, and species. Citizens can create profiles, adopt trees, and mark them as ‘watered’ within the app, making it easy to track contributions to the health of Berlin’s trees. (Ref. 2)
Berlin's trees face growing challenges due to increasing temperatures, reduced rainfall, and exposure to road salt in winter. The hot summers of 2018 and 2019 highlighted the urgency of supporting the city’s trees, which provide cooling shade, clean air, and habitats for numerous animal and plant species. To address this, "Gieß den Kiez" was developed as a platform where authorities, volunteers, and civic society could collaborate to prevent tree dehydration.
The platform maps over 625,000 trees across Berlin and offers additional tools, such as rainfall data from the last 30 days and the locations of public water fountains, which can be used for watering trees. By connecting data from city authorities, the German Weather Service, and OpenStreetMap, the fully open-source platform allows for transparency and accessibility in its operation. (Ref. 6)
The project has proven highly successful in Berlin, with over 10,000 participants actively watering trees, and its model has been adopted in other German cities like Leipzig. "Gieß den Kiez" not only exemplifies a practical response to urban climate challenges but also fosters a sense of shared responsibility and community engagement in caring for urban green spaces. (Ref. 6)