Prevent the frequency and/or intensity of heatwaves

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).

Martinique is a biodiversity hotspot, home to over 1,500 endemic plants, 70% of which are under threat from human activities. In response to these pressures, the Péyi Vert [Green Country] initiative was launched to plant endemic trees and strengthen the island's biodiversity. Beyond simply preserving species, these trees are crucial in maintaining healthy ecosystems, as they provide essential services such as carbon sequestration, shade, food for human consumption, soil decontamination, pollination, and protection against coastline erosion.
Launched in June 2020 by Entreprises et Environnement (EE), a not-for-profit business association representing 80 Martinican companies, the Péyi Vert initiative aims to plant 1 million native trees (either Martinican or Caribbean) over five years. It can be seen as a Martinique-wide strategy to adapt to and mitigate climate change. Péyi Vert facilitates connections between people who want to plant trees and Martinican companies that serve as financial sponsors. The initiative emphasizes conserving natural heritage by planting endangered species, as well as promoting native species that, while not necessarily threatened, provide valuable ecosystem services or contribute to biodiversity restoration.
Between 2020 and 2023, EE reported planting 50,000 trees (Refs 1, 4, 6, 7). Although individuals can make donations, Péyi Vert primarily seeks funding from companies looking to offset their carbon emissions or enhance their Corporate Social Responsibility (CSR). To achieve its goals, the initiative mainly collaborates with municipalities, companies, and farmers (Ref 3).

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).

The Grand Parc des Aygalades project involves the creation of a 14-hectare metropolitan park (connecting Aygalades Park with Bougainville Park and François Billoux Park) that will connect the northern neighbourhoods of Marseille to the port located further south (Ref 1). This project is part of the green conversion of Marseille's northern districts, historically among the most disadvantaged areas in France (Ref 1). The Grand Parc des Aygalades project will enhance the city's greenery, reduce flood risks, create cool zones, restore and develop biodiversity, and significantly improve residents' quality of life and air quality (Ref 1, Ref 2). The environmental and social challenges include reconnecting the populations of these neighborhoods to green spaces, services, education, sports opportunities (Ref 2).
The park project includes redesigning urban infrastructure to improve rainwater absorption and reduce flood risks, addressing the issue of impermeable and artificialized soils that exacerbate flooding during heavy rainfall (Ref 1). It also involves renaturing a 17-kilometre-long stream currently buried under railway tracks, improving flood management and rainwater drainage (Ref 1, Ref 4). The project will also convert a heavily degraded former industrial site, requiring the rehabilitation of polluted soils (Ref 1). Additionally, creating green corridors aims to mitigate the heat island effect, particularly severe in these northern districts due to the high concentration of buildings and concrete surfaces, and the lack of green spaces. Public participation will be encouraged through information meetings, thematic workshops, and an online platform for submitting ideas and feedback (Ref 4).

The "Plan Arbre" is a tool for ecological planning and renaturation aiming to plant 308,000 trees between 2023 and 2029, sourced from the municipal nursery with seeds purchased from local suppliers (Ref 1, Ref 2). In 2023, 14,922 trees were planted, with plans to double this number in 2024 (Ref 1). The project addresses the loss of 50% of Marseille's natural spaces over the past 75 years, aiming to reverse this trend and reintroduce nature into the urban environment (Ref 2). It also tackles issues like drought and heatwaves, particularly in summer, by using trees and shrubs to cool the air, restore biodiversity, reduce air pollution, and enhance public spaces while absorbing CO2 (Ref 2).

The plan is divided into two phases. Phase I focuses on planting in Marseille's 58 parks and 273 squares and gardens, as well as around childcare centres, schools, socio-cultural centres, and sports facilities (Ref 2, Ref 3). From 2020 to 2023, various improvements were made, including playground renovations, installation of misting systems, automatic watering, and the creation of a CrossFit area (Ref 3). Phase II will involve identifying major boulevards, avenues, and streets lacking trees to enhance the urban canopy (Ref 2).
A diverse range of tree species were selected for their drought resistance, water efficiency, and ability to attract biodiversity (Ref 2, Ref 3). The project also focuses on increasing biodiversity and managing invasive species through natural methods to protect trees from pests without chemicals (Ref 3). Furthermore, the initiative includes de-impermeabilizing soils and implementing a smart irrigation system with tensiometric sensors, developed with the start-up GreenCityZen, which has saved 66% of water in two years (Ref 3). The Plan Arbre also promotes citizen participation, with 23 parks selected for community gardening projects, where ten winning associations will receive plants from the municipal nursery (Ref 1).

The municipality of Ciudad Juarez, in collaboration with UN-Habitat, has drafted a redevelopment strategy for an area known as "Paso de Oñate." This intervention falls within the broader framework of "Vision Ciudad Juarez 2040." The plan involves constructing a forested green belt along the southern edge of the Rio Grande (/Bravo) in the northwest part of Juarez, bordering the USA.
Currently in the planning stage, the project aims to restore the ecological function of various degraded areas along the Rio Grande, transforming them into a continuous, green, walkable, and recreational space. The strategy includes allowing vegetation to recover, introducing native plant species, and increasing tree cover to rehabilitate unmaintained parks, derelict areas, and degraded riverbanks. These areas will be equipped with new features and integrated with existing parks, schools, and playgrounds. The envisioned green corridor will enhance walking conditions, improve the perception of safety, offer recreational opportunities for all age groups, and deliver valuable ecosystem services such as temperature regulation, improved air quality, and water retention.
In addition to its ecological goals, the project has a historical and geographical dimension. It aims to incorporate cultural heritage elements, such as the monument of the New Citizen, Paso de Oñate, Turtles Park, and the beginning of the Acequia Madre. It will also connect with other green space initiatives, including the Mega Park "El Chamizal" and the "Corredor Cultural," which runs through the city center.
This intervention is being prioritized due to the area's ongoing social and ecological decline. Paso de Oñate is a critical border crossing point, which negatively affects mobility and air quality. The area also suffers from a high concentration of vacant housing, which contributes to the residents' perception of insecurity. (Ref. 1, 2, 3, 4)

In the city of Ciudad Juárez, the municipality, in collaboration with UN-Habitat, aims to design and create a park that encompasses the yards and unmaintained areas surrounding the railway station, transforming these spaces into an accessible and safe public area. This project covers over 500,000 square meters and addresses not only degraded areas but also several public squares. Described as "a coordinated urban recycling strategy," this initiative seeks to repurpose existing public squares and rehabilitate neglected spaces into vibrant green areas that feature universal accessibility, native vegetation, and urban furniture designed to enhance safety. The project also aims to provide increased recreational opportunities, improve permeability, and introduce additional shaded areas. A key component of improving permeability involves the restoration and incorporation of acequias—traditional historical irrigation systems that absorb and manage excess rainwater, thereby reducing the likelihood of flash floods.
Additionally, the project focuses on the restoration and promotion of significant historical buildings, such as the old railway station and the whiskey factory, integrating them into a larger cultural and sports facility area at the municipal scale. The overarching goal is to revitalize the site through effective coordination with the relevant authorities responsible for the spaces adjacent to the railway station, stretching from Plaza Misión de Guadalupe to Blvd. Municipio Libre. This collaborative effort aims to accommodate both sports and cultural facilities while also creating a green corridor.
Furthermore, the project intends to reforest, redesign, and enhance Plaza Misión de Guadalupe, Plaza Monumento a Benito Juárez, and other residual public spaces and gardens. This initiative aligns with its Public Space Strategy, which emphasizes the development of gender-inclusive and resilient public spaces.(Ref 1, 3, 4).

The Silk District is a real estate project by Prime Kapital in partnership with MAS P.L.C., integrating green spaces into its urban design (1-10). It focuses on regenerating a brownfield site, an abandoned industrial area left undeveloped in one of Iasi's neighborhoods (1). The project aims to revitalize the area, improving its aesthetics, reducing pollution, and repurposing it into a commercial and residential space (1). A key feature of the project is the incorporation of green spaces throughout its design (1).
The development spans 101,000 square meters, with 40,500 square meters (combined) dedicated to green spaces and "car-free" open areas (1, 2, 6, p.2). These green elements are designed to offer spaces for relaxation, recreation, and social interaction, while also contributing to environmental benefits such as air filtration, temperature regulation, rainwater drainage, and soil erosion prevention, all promoting better health for residents (1, 2, 4, 6, p.12). The landscape design includes “green islands” and vegetation-covered roofs for parking structures (4).
Launched in 2021 after receiving municipal approval, the project is ongoing and has already made significant progress, with over 10,000 perennial plants and 401 trees planted (4, 9). Upon completion, the landscape will feature 7,100 square meters of perennials, 3,000 square meters of shrubs, and an urban forest containing 2,400 trees (6, p.12).
The total investment in the project is €20,000,000 (7). In 2024, one of the completed office buildings earned a BREEAM green certification, achieving one of the highest possible scores, in collaboration with the consulting firm BuildGreen (5, 8). The landscape design was carried out by the architectural firm Beros Abdul+ (4). Before receiving approval, the project was opened for public consultation, and an independent online survey showed strong support from the community (15, 16).

The "Ruas Verdes+" (green streets) project, implemented in the parishes of Areeiro and Arroios in Lisbon, is part of a broader European initiative, Conexus, aimed at promoting green solutions in highly urbanized areas (Ref 3). The project primarily focuses on creating a tree-lined pedestrian corridor along Carlos Mardel and Francisco Sanches streets, establishing a continuous axis between the Casal Vistoso Urban Park and the Caracol da Penha Garden (Ref 1). This corridor is designed to mitigate urban heat island effects, enhance ecological connectivity, and improve residents' quality of life (Ref 5). The pilot phase includes planting 20 trees on Rua Carlos Mardel and removing a minimal number of parking spaces to balance urban greening with local needs (Ref 1). Additionally, planters are being introduced in the Bairro dos Actores area to test the community’s response to greening initiatives (Ref 1). The project also involves public participation through gardening workshops, encouraging residents to contribute to the greening effort by adding plants to their balconies (Ref 4). This initiative aims not only to enhance the urban environment but also to foster social inclusion and community engagement while addressing the challenges of climate change in Lisbon's densely populated areas (Ref 5).

Cagliari's waterfront is currently characterized by extensive soil sealing, which has rendered the soil impermeable, leading to a loss of biodiversity and contributing to the urban heat island effect. Additionally, the waterfront is disconnected from the city due to heavy traffic. In 2023, the Municipality of Cagliari launched the "Green Promenade for Cagliari’s Seafront" project, aimed at revitalizing the waterfront and reconnecting the city with its coastal heritage. Led by Stefano Boeri Architetti, the project seeks to transform the area into a continuous green space that integrates pedestrian pathways with shaded public areas, functioning as a "green lung" to mitigate urban heat and enhance biodiversity.
The initiative will introduce over 200 new trees and 5,700 square meters of green space, creating a park that beautifies the area, improves air quality, and lowers local temperatures. A key focus of the project is fostering cultural and social inclusion by developing new community hubs that encourage diverse activities and strengthen social cohesion. Additional features include recreational areas, sports fields, and outdoor seating. (Ref. 1, 2,3)
The project also aims to enhance social inclusion, environmental sustainability, and urban connectivity, ultimately transforming the waterfront into a vibrant public space that reflects Cagliari’s identity.
However, the lengthy construction process has disrupted local businesses and reduced foot traffic, making the area less attractive during the redevelopment phase. (Refs. 10, 11, 12 & 13).