Citizens or community group

In the bay of Fort-de-France, mangroves cover nearly 1,300 hectares, representing about 70% of the total mangrove area in Martinique. This plant formation, characteristic of tropical marine environments, is essential for the ecological balance of the bay. Mangroves act as filters, purifying marine and river waters, protecting the coastline against erosion, and providing habitat for various marine flora and fauna.
However, this fragile ecosystem is threatened by wave-induced erosion, urbanization, the spread of invasive species, and pollution. In response to these challenges, the French Coastal Protection Agency (Conservatoire de l'espace littoral et des rivages lacustres, CELRL) and its partners have launched an initiative to restore several mangrove areas as part of the “Contrat de la Grande Baie de Martinique" which is a collaborative initiative aimed at the sustainable management and restoration of the coastal and marine environment of the Greater Bay of Martinique. This contract typically involves partnerships between various stakeholders, including government agencies, local municipalities, environmental organizations, and community groups. The project identified several sites totaling 3.81 hectares in the Greater Bay area that require reclamation.
The project aims to restore mangrove populations by creating favorable conditions through actions such as clearing invasive species and trash, followed by replanting with white, black, or red mangrove seedlings, depending on the environmental characteristics of each site. Additionally, the initiative seeks to engage the public and youth through volunteering days and awareness campaigns (Refs 1-9).

The Prinzessinnengarten Kollektiv Berlin is a community garden in the New St Jacobi Cemetery in Berlin-Neukölln that invites people to join in gardening and experience nature. As part of open gardening days, people can participate in the design of the garden areas and gain experience in the local, ecological cultivation of useful plants. The main aim of their work is to provide opportunities for education and participation. Activities are open to everyone and range from sowing, planting and harvesting to seed production, processing and preserving vegetables, keeping bees to questions of community-based urban habitat design.The community also has its own farm shop where seeds, food and processed products are sold. (Ref. 1; Ref. 4) Numerous projects for recycling and upcycling, innovative cultivation methods, organic beekeeping, composting methods and post-fossil mobility use the Prinzessinnengarten as a platform for sustainable urban living. Artists also work in the garden with participatory methods on the question of how cities and their coexistence can be designed in a sustainable and resource-saving way. Outside the Prinzessinnengarten, offshoot gardens are set up and collaborations are developed to build nationwide and European networks. Through lectures, workshops, study visits and participatory research in the garden, we endeavour to include and further develop the topics associated with the Prinzessinnengarten in discussions and education. (Ref. 7)

The project is located on a cemetery, which has been partially closed since 2016. This means that burials are no longer carried out on the site and the existing rights of use of the 500 or so remaining graves will no longer be extended after expiry. The church association lends the land to the project in exchange for maintenance work on the surrounding grounds. (Ref. 6)

The rate of deforestation in the Brazilian Legal Amazon in 2023 was consolidated at 9,064 km2. Initiatives that promote forest restoration in this biome are emerging to overcome this scenario. One such initiative is Floresta Productiva which aims to reforest more than 200 hectares of degraded land in the southwest of the Brazilian Amazon, known as the ‘arc of deforestation’ (1). Led by the Instituto Socioambiental in partnership with the NGO Rioterra, it focuses on creating and disseminating native forest restoration models that combine ecosystem recovery with income generation for rural producers in Porto Velho (2). By fully integrating local communities, the project promotes traditional agroforestry practices (muvuca) and trains communities to maintain the planted land. This not only restores the forest but also provides economic benefits through the cultivation of timber, fruit trees and other species (2), strengthening sustainable agriculture, breaking the cycle of deforestation and restoring deforested areas through various native species grown in nurseries (1). The project is being developed in the cultivation area of the Amazon Bioeconomy Centre (CBCA), from 2023 to 2025, where it will directly benefit the rural community of Vila Nova de Teotônio (3).
The project started in 2019 and has impacted other communities in the area, such as the communities in Nova Mutum Paraná and Ji-Paraná (1). During these years, more than 123,000 trees have been planted in agroforestry on about 110 hectares of land, and edible forests have been created. Since 2022, a new planting phase has been underway, to plant more than 100,000 trees of 87 native species on 40 hectares of degraded forest (4). In conclusion, this project focuses on the development of agroforestry in the face of widespread monospecific soybean fields and intensive cattle ranching (3); the creation of edible forests (3); and the restoration of forest cover to ensure the long-term resilience of the forest (3).

The revitalization and environmental recovery initiative in the Almirante Colón neighborhood of Cartagena focused on transforming green spaces and addressing environmental hazards posed by improper waste disposal and urban degradation. The primary goals of the project were to enhance urban green spaces, improve community well-being, and mitigate environmental hazards such as pollution and improper waste management (ref 1,2). The initiative involved multiple stakeholders, including the local government, community leaders, and private sector actors. The Gerencia de Espacio Público y Movilidad led the revitalization of three parks, focusing on cleaning up waste, maintaining green areas, and upgrading recreational facilities. Parallelly, Veolia, a private sector partner, worked with community leaders to recover neglected areas that were previously used for dumping mixed waste and beutify the environment. These efforts included planting activities, installation of solar lamps, and community education on proper waste disposal practices​ (ref 1,2). The revitalization of the parks benefited over 400 families, providing them with safe and clean recreational spaces. The project also successfully eliminated a significant dumping site, reducing pollution and enhancing the neighborhood's aesthetic appeal. Moreover, the initiative fostered a stronger sense of community ownership and responsibility towards maintaining the improved environment​ (ref 1,2).

The Ringsend Open-Air Laboratory project in Dublin, Ireland, is part of a broader effort to adapt urban areas to increasing climate change risks. This initiative focuses on installing green roofs and deploying a network of environmental sensors to enhance urban resilience. Launched in 2018 under the Horizon 2020 OPERANDUM project, the effort seeks to find nature-based solutions for climate change impacts worldwide. Led by the University of Bologna, OPERANDUM involves over 20 partners, primarily in Europe, working together to address environmental challenges like flooding, drought, and coastal erosion through the establishment of ten "Open Air Laboratories" globally.
In Dublin, the project aims to bolster flood resilience in Ringsend, a critical economic area near the city’s tech district, which faces substantial flood risks due to its low elevation and proximity to the Dodder River. This river, which flows through both rural and urban areas before meeting the River Liffey near Ringsend, has caused property and infrastructure damage from extreme rainfall and combined river and tidal flooding.
Green roofs play a key role in mitigating urban flood risks in this project. These rooftop gardens absorb large volumes of rainfall before it reaches the streets, easing the load on existing flood prevention systems like storm drains and gullies and reducing the need for additional "grey" infrastructure. Based on community insights and recommendations, construction has begun on a green roof on top of the CHQ building in Dublin’s Docklands, in partnership with Dogpatch Labs.Complementing this, over 100 sensors have been deployed in recent research trials across Dublin. OPERANDUM researchers are now building on this foundation to create a denser, more reliable, and cost-effective sensor network, with data from earlier low-cost sensor trials made publicly accessible via Dublinked, Dublin’s open data platform, and exploring the use of LPWAN for environmental sensing. (1-5, 7)

Torslanda School is a newly built elementary school (years 0-6) where the schoolyard includes innovative ways to manage rainwater. The school was initially part of the Rain Gothenburg project, which aims to make the city, and this school, the best in the world when it rains. It was also a pilot project within the city's "equal building" initiative, aiming to make indoor and outdoor environments accessible and attractive to everyone regardless of gender identity, functional diversity or age [Ref. 1]. The main element of the schoolyard is a "river" to which water will be led when it rains, combining stormwater management with opportunities for play and education. The system will retain about 310 m3 of water and treat it before releasing it to a recipient. The river will be used to teach the children about climate, ecology, biodiversity and the water cycle. The river and schoolyard are connected to a natural wetland [Ref. 3, 4]. The school is run by the City of Gothenburg, who initiated the project, employing an architecture firm and a construction company to design and build the school and schoolyard [Ref. 3-5].

The "Mangle Verde" project is a community-led intervention aimed at reforesting mangrove areas in Cartagena, particularly around the Ciénaga de la Virgen and Ciénaga de Juan Polo. Initiated by Gloria Sánchez and other members of the Villa Gloria community, this project is a response to the environmental degradation caused by urban development, including the construction of a viaduct, and the damages inflicted by invasive settlements and pollution​(ref 1,4). The primary goal of the project is to restore the mangrove ecosystems, which are essential for maintaining water quality, preventing coastal erosion and supporting marine biodiversity conservation (ref 4). In addition, this initiative provides socio-economic benefits by fostering ecotourism and increasing fish populations, which directly benefit the local fishing economy​(ref 1). The "Mangle Verde" project emerged as a grassroots response to compensations granted by the Concesión Costera for the damage caused by infrastructure projects in the region. Local residents of Villa Gloria, recognizing the importance of the mangrove ecosystem, established nurseries in their homes where they cultivate three types of mangroves (ref 2,4). So far, the initiative has planted over 26,860 mangrove saplings and is committed to continuing the reforestation efforts, which also include cleaning and maintaining the canals around the mangroves​ (ref 1). Beyond ecological restoration, the project also addresses key environmental risks in Cartagena, including coastal flooding and habitat degradation, driven by both natural phenomena (e.g., tides) and human activities such as urban sprawl and illegal dumping (ref 6, 7).

The initiative consists of an afforestation campaign promoted by the local government of La Paz, with the objective of planting 10,000 trees and shrubs (1 & 2). Carried out between 2023 and 2024, the campaign included plantations across all the macrodistricts of La Paz (1). To ensure the campaign's success, the municipality encouraged the participation of volunteers from various institutions, such as public services, environmental groups, schools and universities, neighborhood associations, church groups, and even Army and Navy units (1 & 2). The trees play specific roles in mitigating climate change, improving air quality, reducing odors from nearby landfills, and decreasing the risk of landslides and soil erosion (3 & 4). Furthermore, the campaign aims to foster environmental awareness among citizens and replace trees lost due to illegal deforestation (1).

The species selected for planting were provided by EMAVERDE, the public company responsible for managing green spaces in the city. The selection included primarily native species, along with a few introduced ones, all chosen for their resilience to La Paz's varying climate conditions (1, 2 & 4). Given the challenging climate and difficult soil conditions, the municipality informed volunteers about the importance of maintaining the saplings, particularly during drought periods, to ensure their proper growth (1 & 2). The campaign also supported the municipality’s urban development plan (Plan Territorial de Desarrollo Integral "Para Vivir Bien") and the "Plan Integral de Recuperación de la Tormenta a la Esperanza," the latter developed in response to extreme rain events and floods that occurred during the campaign months (5).

The City of Mobile has developed and implemented a Storm Water Management Program (SWMP) as required by the regulations of the Environmental Protection Agency (Ref 1). Flooding is a significant issue in Mobile, occurring frequently throughout the town (Ref 3). The SWMP aims to protect water quality and prevent harmful pollutants in stormwater runoff from entering the Municipal Separate Storm Sewer System (MS4) area (Ref 1). Stormwater runoff refers to rainfall that does not seep into the ground but instead flows over yards, streets, parking lots, and buildings, eventually entering the storm sewer system, which directs it into creeks, rivers, bays, and the Gulf of Mexico (Ref 1). Stormwater can collect pollutants such as trash, debris, sediment, heavy metals, oils, and hazardous household materials. Additionally, development increases impervious surfaces, leading to more stormwater runoff (Ref 2).

Rapid urbanization and a population density of 6,247 people per km² have placed significant stress on Nairobi's natural resources (Ref 1). The 40-km long Nairobi River Basin, originating from the Ondiri Swamp, serves as a vital water source for the city (Ref 1, 2). However, it has suffered severe pollution from untreated sewage, solid waste, industrial contaminants, plastics, and agricultural runoff (Ref 1, 3). This degradation has had a serious impact on the ecosystem, local residents, and biodiversity (Ref 3).

To address these issues, the Nairobi River Basin Programme (NRBP), sponsored by UNEP, was launched in 1999 (Ref 4). Since then, government and non-state actors have worked together on solid waste management, riparian restoration, and wastewater control (Ref 1). The program was implemented in two phases: Phase I (2003–2006) and Phase II (2006–2009), involving stakeholders from the government, private sector, and civil society (Ref 1, 4, 5). Despite these efforts, a study from 2017 found significant tree removal along the river, and between 1988 and 2014, encroachment into the 30-meter riparian buffer zone dramatically increased, particularly between 2010 and 2014, further degrading the river’s health (Ref 1).