Enhanced carbon sequestration

In 2001, the local municipality of La Paz, in collaboration with the International Union of Architects (UIA), launched a design contest to create a central park within a protected natural area (3). The park's aim was to develop urban infrastructure while connecting nature with the city (3). The winning architectural design envisioned an infrastructure that would harmonize with the existing natural surroundings and minimize interference with the environment (4).
The park's implementation included pedestrian and bike pathways, numerous panoramic viewpoints, facilities for exercise and cultural events, buildings dedicated to science, historically significant monuments, playgrounds, and the rehabilitation and creation of multiple green spaces (1 & 4 to 6).
While most of the project was completed by 2009, the area's exposure to recurrent landslides, droughts, and illegal waste disposal, combined with ongoing degradation, has necessitated afforestation efforts and maintenance actions from the municipality to ensure the protection of the natural area and enhance its benefits (7 & 8). Recently, the park has been part of a national citizen monitoring program for species, which has improved the categorization of wildlife in the area (11 & 12). Additionally, 2,000 trees were planted in the park in 2023 as part of a reforestation campaign, and cleaning and watering maintenance work has been carried out to support their growth (7 & 13). This initiative is part of a larger project to revitalize the park (10 & 13).
Overall, the park aims to protect local wildlife and plant species while acting as a "green lung" for the city, regulating the climate, providing recreational spaces, and improving livability (14).

The Green and Blue Axis (Eixo Verde e Azul, EVA) is an inter-municipal green corridor project connecting the municipalities of Sintra, Oeiras, and Amadora through a 15-kilometre green ecological axis along the Jamor River (Ref 2). It aims to renaturalize the river, improve water quality, and control flooding while promoting sustainable mobility through pedestrian and cycling routes (Ref 5). The project also enhances public access to green spaces and cultural heritage sites, such as the Queluz National Palace (Ref 6). EVA supports the Lisbon Metropolitan Area’s regional strategy for climate change adaptation, risk prevention, and low-carbon economy (Ref 4). Funded by the European Regional Development Fund and municipal budgets, the project has an overall investment of €11 million (Ref 1). EVA exemplifies inter-municipal cooperation, overcoming policy conflicts to achieve shared environmental, social, and economic goals, making it a model for integrated territorial development (Ref 4). The project’s long-term impact includes reduced carbon footprint and increased territorial cohesion.

Located in the Lima district of San Isidro - the heart of commercial activity in Peru - the Real Dos Tower is a prime office building in the Centro Empresarial Real de San Isidro. It was inaugurated in 2018, and it is distributed over 23 levels (14 floors and 9 basements) and enjoys a landscaped green roof (1162 m2) at the crown of the building and numerous outdoor vertical gardens at full height (2365 m2) on the three main fronts (1, 4). This project was a finalist in the 2018 Mipim Awards, considered the ‘Oscars’ of world architecture, and stood out for its architecture and design, due to its attributes of innovation and sustainability (2).
This building has managed to create harmony between design and efficient use of resources. It is characterised by a glass façade with colourful movable shutters and symbolic Peruvian designs (2, 3, 6). It has green walls on the three main fronts, four daylight fronts and a roof garden (2). The architect, Jean Nouvel, worked together with ARVE Peru on the overall landscape plans for the Real Dos tower (1, 3).
This is part of the façade remodelling project of the Camino Real Towers in the Real Business Centre, led by the real estate company Grupo Centenario (1, 2, 3, 4, 5, 6). This overarching Project has sought to develop 4,475 m2 of vertical gardens and roof gardens, which have a technified irrigation system to generate efficiencies in water use, meeting the plants' water requirements in the different seasons of the year. Their implementation helps to filter CO2 and renew the O2 in the office complex.
The ARVE group describes these actions as conducive to creating thermal barriers and sound insulation, a better environment for rest, work and entertainment and increasing property value (7)

The Metropolitan Linear Park is a project initiated by the national government of Bolivia, funded by the Inter-American Development Bank (IDB) (1-8). The proposed park will be located along a disused railway corridor between the cities of La Paz and El Alto, spanning 18.2 km (8, p. 8). The project involves the construction of a linear park, divided into five sections, each with distinct objectives, uses, and designs (8, p. 9). This large-scale initiative aims to improve access to public spaces in La Paz and El Alto, enhance connectivity between the two cities, protect surrounding biodiversity and natural spaces, and strengthen resilience to and mitigate the effects of climate change (3 & 8, pp. 11-12).
To achieve these goals, the project design includes outdoor sports and recreational facilities, pedestrian and cycling circuits, as well as the restoration of parks, squares, and public spaces adjacent to the park corridor (8, p. 9). Some features include balcony corridors, flower and food-producing urban gardens, and viewpoints (5). The project also plans for the re-vegetation of the area with native species and aims to stop the environmental degradation of surrounding natural environments, such as the Pura Pura forest, which has been suffering from ongoing deforestation and waste dumping (8, p. 9). These efforts are expected to increase and support biodiversity in the area (7 & 8, p. 12).
Additionally, the project emphasizes social inclusion, with policies designed to incorporate women, indigenous populations, and persons with disabilities (8, pp. 7-8). The park is intended to raise awareness about climate change and biodiversity, ultimately improving the quality of life and health of nearby residents and the citizens of La Paz and El Alto (8, p. 13).

Seaweeds are of immense value to marine ecosystems, and Kelp, the largest of them all, forms spectacular underwater forests that provide habitat for fish, clean the water, and sequester carbon. Unfortunately, large swathes of these subaquatic forests have disappeared from the coasts of many European countries, including Portugal (Ref. 2).
The "Sea Forester" project in Cascais aims to restore local kelp forests, which are essential for marine biodiversity and carbon sequestration. In collaboration with the Câmara Municipal de Cascais and Mossy Earth (social enterprise), the project assesses the historical and current state of seaweed populations and identifies environmental stressors. It employs innovative techniques like the "green gravel" method to restore kelp ecosystems. This project supports the region’s blue economy and resilience to climate change through carbon offsetting and enhanced ecosystem services (Ref 1; 6; 7). Supported by the EEA Innovation Grant, it combines scientific research and community engagement, positioning Cascais as a leader in marine conservation efforts (Ref 6).

Alexandria is one of the vulnerable cities facing climate change (1). From rising sea levels, pollution, extreme rise and fall in temperature and the urban heat island effect, Alexandria is battling significant challenges (1). The city is also worldly renowned for it beaches and gardens that act as the lungs through which the city breathes, and are considered a haven for its people (1). Unfortunately, in the last ten years, there has been a decrease in parks and green areas, which is a cause for concern (1). This shrinkage comes at the expense of urban expansion and the establishment of Commercial and profitable projects, which is a challenge facing the environmental balance and cultural heritage of the city (1). To address the nature of the challenges and climate changes and their effects in Egypt, the president launched the "The 100 Million Trees Initiative" was brought into action in 2022 as part of the Egypt 2030 Vision (2-3). The campaign is meant to double the per capita share of green spaces across the country, improve air quality and people’s health, and reduce greenhouse gases. It will also aim to recoup economic benefits from the trees, including wood and olive oil (3). As part of this initiative, the governor of Alexandria was tasked with taking care of the green spaces and improving the aesthetic and civilizational level, within the scope of Alexandria's neighborhoods and centers (4). In 2023, the gardens department carried out the planting of 812 trees and shrubs of various types within the scope of Al-Muntazah 2 Neighborhood during Week 25 to continue the work of the presidential initiative to plant 100 million trees in the governorate's neighborhoods (4).

The Stora Amundö and Billdal archipelago nature reserve is in the southernmost part of the City of Gothenburg. The proximity to the city makes it a popular recreational destination, with about 73000 visitors each year. In 2018, the area was protected as a nature reserve to preserve its recreational, natural and historical values. The status as a nature reserve prohibits any exploitation and other harmful activities in the area. The area of the reserve is 1103 ha, of which 259 ha is land area and the rest is water [Ref. 1-3]. The management of the reserve includes promoting recreational and educational activities by creating new entrances, paths and signs, as well as holding guided tours. The management also includes restoring and improving terrestrial ecosystems such as grasslands through mowing and grazing and deciduous forests through selective clearing. A wetland has been restored to promote biodiversity further [Ref. 2, 4]. The reserve was created and is managed by the City of Gothenburg, the process of creating it involved consultation of stakeholders such as land owners, government agencies and NGO's [Ref. 1]. Some local landowners disagreed with the borders of the nature reserve having an impact on their land, leading to an appeal that was ultimately denied [Ref. 5, 6]

Biotope City Wienerberg is located in the southern part of Vienna on a 5.4-hectare site that once housed a Coca-Cola factory. It lies at the edge of the Wienerberg recreational area, surrounded by business parks and tower blocks to the west and predominantly detached houses to the east (Ref. 1).
The project embodies the concept of an "urban biotope" (Ref. 2), grounded in the principle that nature's mechanisms of self-regeneration are essential for mitigating the challenges of urban living and climate change. By integrating urban and natural spaces, Biotope City fosters both human-nature connections and social interactions through activities like community gardening. The project’s centerpiece is its extensive green infrastructure, including trees and green roofs, which serve to cool the microclimate, purify the air, enhance water retention, and create carbon sinks while providing habitats for local wildlife. These green spaces aim to improve physical health through cooling effects on hot days and support mental well-being with their calming influence (Ref. 1; Ref. 2).
Biotope City encompasses:
Around 980 flats, including 400 subsidized flats and 200 SMART flats
A school, a kindergarten, and 2,000 square meters of children's and youth playgrounds
600 square meters of community gardens and 3,850 square meters of ground-floor gardens
250 trees, 8,900 square meters of meadows, and 13,600 square meters of green roofs
2,200 square meters of façade greening
The inner courtyards and roof areas are designed for gardening, while façades are greened, and balconies are equipped with integrated plant troughs. Even the spaces between buildings are climate-effective, featuring unsealed catchment and seepage areas to manage water sustainably (Ref. 1).
The project’s implementation took 18 years and involved collaboration among various stakeholders. The concept was initiated by the Biotope City Foundation and funded by eight different investors (Ref. 2).

The Tirana Vertical Forest is part of the city's 2030 Master Plan and aims to enhance urban biodiversity and create green spaces through innovative urban design (Ref. 1,2). The project was developed by Stefano Boeri Architetti, the same studio that has designed similar, well-known structures in cities like Milan, Utrecht and Nanjing (Ref. 6). The completion of the 21-floor building is expected in late 2024 and will feature 105 apartments and a commercial ground floor as well as 145 trees and over 3,200 shrubs and bushes which are integrated into the balconies and façade of the project (Ref. 1,2,3). Various Mediterranean plants have been incorporated, including colourful, scented and aromatic types, which harmonize with the local ecosystem. To maximise the space available for green features, a dynamic structure with alternating balconies and full-height windows has been built (Ref. 1,2). Ultimately, the project anticipates improving air quality, reducing noise, and providing insulation. The greenery is expected to capture fine particulate matter and up to 8 tones of Co2 per year while also creating a healthier microclimate for those inside the building (Ref. 1,6).

The "Tree Plantation Month" is an annual national initiative in Romania, organized by the Ministry of Environment, Water, and Forests through the National Directorate of Forests. This initiative focuses on afforestation, forest regeneration, and raising awareness about the ecological benefits of forests, while promoting sustainable behaviors (4, 9, 10). Having been in place for 60 years, the program has recently aligned with the principles outlined in the 1991 Paris Declaration on the Sustainable Development of Forests (10). At the national level, the initiative is regulated with overarching goals aimed at protecting and sustainably managing Romania's forests (9). The program allows for the involvement of various actors, including public institutions, municipalities, NGOs, and schools, who collaborate with regional forestry directorates to implement local activities (4).
In 2019, as part of this initiative in Iași, the Asociația Tineretul Ortodox Român Iași (ATOR), a youth-led religious association, actively participated in one of the campaigns . They planted 1,000 tree saplings in the Moara de Vânt district, an area that had suffered from deforestation and was prone to landslides (1, 2). The afforestation efforts were designed to address these environmental challenges by stabilizing the soil, reducing the risk of overflow and flooding, maintaining soil moisture, and regulating extreme temperatures (1). To ensure long-term success, the saplings were regularly monitored, and restoration efforts were carried out in cases where the trees were affected by fires or drought (3).