Climate change

Berlin has faced severe water shortages in recent years, with ponds, small lakes, and pools suffering significantly. Many have dried out or disappeared, causing habitats for countless animals and plants to vanish. Urbanization exacerbates the issue, as more areas become sealed, preventing rainwater from replenishing soil and water bodies. Recognizing the urgency, Berlin introduced the Eco-Account, a strategic reserve of areas and initiatives to mitigate the effects of urban development on nature and landscapes. Central to this is the Blue Pearls for Berlin program, focusing on revitalizing small water bodies to restore biodiversity and ecological balance.
The project identified approximately 30 ponds, pools, lakes, and ditches from over 100 candidates to be transformed into "blue pearls." These revitalized areas will support local ecosystems and improve Berlin’s water cycle. The Berlin Rainwater Agency, alongside departments responsible for nature, climate protection, and water management, is spearheading the initiative in collaboration with the Berlin Nature Conservation Foundation.
Two pilot sites—the Schleipfuhl/Feldweiher water complex in Marzahn-Hellersdorf and the Lankegrabenteich in Steglitz-Zehlendorf—were prioritized for restoration in 2024. These efforts include improving water quality and creating diverse habitats for wildlife. Enhancing small water bodies not only provides a refuge for animals and plants but also contributes to climate adaptation. Restored ponds and lakes can cool surrounding areas and improve the urban microclimate by utilizing locally accumulated rainwater. Blue Pearls for Berlin, approved by the Senate in 2022, aligns with the city’s Eco-Account framework, ensuring that these restored blue spaces offset ecological damage caused by infrastructure and urban projects. The initiative offers Berliners new ways to experience nature, fostering a balance between development and environmental preservation. (Ref. 1, 2, 4, 6, 7)

Maya’s Farm is a small, CSA (Community Supported Agriculture) sustainable urban farm located in Phoenix, Arizona, where urban development has limited farmland availability. In 2020 alone, Phoenix lost nearly 200 acres of farmland to urban sprawl, putting farms like Maya’s at risk. The farm faced potential closure until the City of Phoenix intervened, providing funding through the Farm Preservation Program, which established the city's first urban agricultural conservation easement. Maya's Farm strives to inspire a local appreciation for sustainable food and to bring renewed value to local food systems.
The farm’s mission is to provide accessible, fresh, locally grown produce to the community while promoting awareness of healthy, sustainable food practices. Through its CSA program, members receive a weekly produce box and have opportunities to come together, honor food traditions, and share stories over locally harvested food. As a CCOF (California Certified Organic Farmers) certified organic farm, Maya’s Farm is committed to organic practices that exclude GMOs, nurture the soil, foster biodiversity, and innovate growing systems. These methods result in healthy soil and cleaner air, contribute to carbon sequestration, and support critical wildlife habitats.
To broaden educational outreach, Maya’s Farm offers several programs that promote sustainable food practices, including its CSA program, an edible classroom series, and a partnership with Arizona State University (ASU). Through this ASU partnership, students gain hands-on experience by participating in daily farm operations.
Building stronger community connections is another cornerstone of Maya's Farm’s work. The farm collaborates with local restaurants, farmers' markets, and community groups to expand its impact. Maya’s Farm, ASU, and Arizona Sustainability Alliance launched an agrivoltaics project with solar-shaded crops. (2, 9, 11, 13, 15)

"The Neighborhood, Environment & Water Research Collaborations for Green Infrastructure (NEW-GI)" project in Warrendale, Detroit, aims to advance green stormwater infrastructure (GSI) knowledge and practice in legacy cities by integrating research on water quality, community well-being, governance, and ecological design. This collaborative effort, involving community members, government entities, and academic researchers, seeks to develop evidence-based strategies for sustainable stormwater management while enhancing urban landscapes and improving residents' quality of life.
In its first phase (2014-2015), the project created bioretention four bioretention gardens, each on two vacant residential properties in the Warrendale neighborhood. in Detroit's Warrendale neighborhood. These sites, constructed by the Detroit Water and Sewerage Department (DWSD) on vacant lots owned by the Detroit Land Bank Authority (DLBA), were monitored for water quality, and resident surveys were conducted to gauge the gardens' impact on neighborhood satisfaction and stormwater management.
The second phase (2016-2019) expanded the scope to refine GSI designs to reduce maintenance needs and further assess their effects on water management and community well-being. It also explored governance structures that impact GSI success, both in Detroit and other legacy cities, contributing to the development of guidance documents for GSI planning and decision-making.
Funded by the Fred A. and Barbara M. Erb Family Foundation, the NEW-GI project represents a transdisciplinary approach to urban ecological challenges, offering valuable insights into how GSI can deliver both environmental and social benefits in cities like Detroit.
(Ref.1,2)

The Miraflores Bicentennial Park has been built on the Malecón de la Reserva and the Quebrada de Armendáriz. It was inaugurated in June 2022 as one of the created projects within the framework of the commemorations of the 200 years of Independence celebrations (1). It is considered a new green lung of Lima (2), as it has a green area of 30,400 square metres and stands on one of the cliffs of the Costa Verde (1). It has a system of terraces that replicates the construction model of the Incas, which has made it possible to additionally reinforce the soil and the slopes with the use of retaining walls up to 10 metres high, with horizontal geogrids and vertical geocells (1, 2). It was structured on a stabilised slope in order to mitigate the risk of landslides (4), and an irrigation system was implemented to stabilise the soil (4).
This space was built as a biodiversity garden with more than 160,000 xerophilic coastal species with low water consumption, 300 trees and 80 palm trees. It also offers places for tourism, such as viewpoints and squares, where cultural events, open-air activities and rest areas are held (1). It also aims to connect aspects of landscape conservation, preservation of biodiversity in the city, and the construction of a cultural landscape in which human action is complementary and friendly to the natural environment (9). Finally, it seeks to contribute to the reduction of the municipality's carbon footprint by reducing the harmful effects of urban expansion on the Lima cliff ecosystem, such as deforestation, water pollution and loss of biodiversity (9).

In 2023, the municipality of Cagliari initiated a project to transform 50 school gardens into vibrant, multifunctional outdoor spaces that enhance education and recreation. Co-funded under an EU program, this initiative aims to create environments where students can learn and play outdoors, taking advantage of the city’s favorable climate. The gardens are being upgraded with new features, such as trees, educational vegetable plots, diverse plant species, playground equipment, and furniture, to provide versatile spaces for learning, sports, and play.
Automated irrigation systems are being installed in each garden, conserving water by adjusting based on soil humidity and detecting leaks. This technological upgrade ensures efficient maintenance of the green spaces.
Overall, the project seeks to enrich the educational experience by integrating nature into daily school life. It aims to promote students' physical and psychological well-being through more opportunities for outdoor learning and activities, fostering a connection with nature, and improving the overall quality of the school environment (Refs. 1, 2, 3, 4 & 5).

The BASIC Cartagena Project is an applied research initiative focused on developing tools for integrated coastal water resource management in Cartagena, Colombia (ref 4). It is funded by the International Development Research Centre (IDRC) of Canada, and EAFIT University leads it in collaboration with the University of Los Andes, the University of Cartagena, the Foundation H.E.O., and the Regional Corporation CARDIQUE (ref 4). The goals are to reduce pollution, conserve ecosystem services, and implement climate change adaptation strategies in the coastal area (ref 3). The studies focus on Cartagena Bay (Recognized as the most polluted body of water in the Caribbean), the Dique Canal and the Magdalena River watershed, the local communities in the areas surrounding Cartagena Bay, principally the communities of Ararca and Barú (ref 5). During its first phase (2014-2017), the project concentrated on diagnosing pollution levels and sources. This included extensive monitoring of water quality and the socio-economic conditions of local communities (with a public health focus). The second phase (2018-2021) focused on developing early warning systems for pollution, educational programs, and knowledge transfer through community engagement. The third phase (2023) plans to expand the same activities from phase 1 & 2 to the Rosario and San Bernardo Islands, with continued collaboration among scientists, authorities, and local communities​ (ref 2, 3). Among its most significant achievements are the production of high-level scientific knowledge and the training provided to communities and environmental authorities. A notable impact of the project is its contribution to the formulation of seven policies, including the creation of an intersectoral committee for the environmental management of the Bay of Cartagena. This committee, for the first time, brings together various stakeholders, including fishing and tourism communities, to make decisions about environmental management (3)

The requalification project for Viale Buoncammino in Cagliari aims to revitalize the historic promenade while preserving its original layout and functions. Launched in September 2022 and completed in 2023, the project focused on enhancing the area’s aesthetic and environmental appeal. Key improvements include expanding green spaces by adding 560 new square meters, enhancing vegetation, and reducing surface runoff. This involves increasing permeable surfaces around existing trees to boost natural vegetation, improve bioclimatic comfort, and manage runoff during heavy rains.

The project also includes reconstructing pavements, optimizing seating areas, and repositioning urban furniture for better functionality and aesthetics. A modern LED lighting system will be installed to reduce energy consumption and operational costs, supporting the project's sustainability goals. The area is included between via Anfiteatro, viale Buoncammino and viale Giussani and also includes the squares F.Pilia and Marongiu-Pernis. The project aims to restore Viale Buoncammino as a dynamic social and cultural hub in Cagliari, appealing to both residents and visitors. (Refs. 1, 2, 3 & 4).

The Urban Forestry Plan for Cartagena, led by EPA Cartagena, outlines a comprehensive strategy for enhancing the city's green infrastructure. The plan focuses on selecting suitable tree species, planting, and management to achieve several goals: reducing heat through shade, creating microclimates, protecting against climatic events such as coastal erosion and windstorms, enhancing food security, and enhancing the landscape's beauty. Over 10 years, the plan aims to establish at least 100,000 additional trees, increase overall tree cover, enhance accessibility to green spaces, and build a main ecological structure based on natural resources and biodiversity. It also emphasises the importance of local knowledge and resources (ref 1).
Formulated with community input, the plan commenced in 2013 and involved a detailed assessment of existing urban vegetation and climate conditions, utilising tools such as iTree. The development included international conferences and expert consultations to ensure a robust and informed approach (ref 1).

Liquid 3 is the first urban photo-bioreactor in Serbia, developed by an interdisciplinary team at the Institute for Multidisciplinary Research at the University of Belgrade (Ref. 1,2,3). Prompted by an appeal of the United Nations Development Programme (UNDP), the team was eager to find novel approaches to combat the city's severe air pollution issues while being space efficient and providing year-round benefits (Ref. 3). The key to the bioreactor are algae which are very efficient in sequestering carbon and filtering heavy metals from the air (Ref. 2). A Liquid 3 feature can be quickly set and occupies a plot of only 3 m². Some of its benefits include its ability to withstand high levels of air pollution and its ease of installation on surfaces like walkways and other sealed infrastructure (Ref. 2,3). Additionally, by design, Liquid 3 integrates amenities such as power outlets, a bench, and nighttime lighting (Ref. 1). The selected strain of algae can tolerate temperatures between 5-35°C making it deployable all year. However, monthly maintenance is required, during which the water and algae are replaced—both of which can be repurposed, for example, as fertilizers (Ref. 6).The project has received global media coverage as well as a prize for the best innovative and climate-smart solution in Serbia. Its success has prompted the installation of two more such bioreactors in Serbia, with interest coming from other countries such as Hungary and the UAE (Ref. 1,4).

The Parque Lineal de Crespo in Cartagena, Colombia, is an urban green space built in 2016-2017 that had fallen into neglect (ref 4) and recently has undergone revitalization initiatives (ref 2). Announced in January 2024 by the Mayor of Cartagena, Dumek Turbay Paz, the project aims to reclaim and enhance this public park as a hub for recreation and community activities, fostering urban well-being and environmental stewardship​ (ref 2 and 3). The local government spearheads the intervention, and the Instituto Distrital de Deporte y Recreación (IDER) has been tasked with the park's management, ensuring its upkeep and the development of activities. The project was launched following an inspection by the Mayor and other local officials, who underscored the need for better infrastructure, safety, lighting, and green coverage through tree planting ​(ref 2 and 3). The primary objectives of the Parque Lineal de Crespo project include revitalising the park through enhanced maintenance, security, and the introduction of recreational and sports facilities. The project also aims to relocate weekend recreational activities, such as a popular bike path (ciclovía), from the congested Avenida Santander to the park, thereby reducing traffic disruptions and enhancing safety ​(ref 2 and 3). The park is relevant for the city because it combats coastal erosion caused by the rising Caribbean waters (Ref 1). The Park aims to be an icon of culture and recreation (ref 1). The project inspired a neighbours initiative, the Friends of the Crespo Linear Park, are a non-profit organization whose objective is to collaborate in the conservation of the Park by contributing awareness initiatives to the population, alerting authorities, and developing new ways to interact with the environment, such as guided bird watching activities and sports (ref 1).