Environmental quality

The Gangxia 1980 green roof, a pilot of the Green Cloud project, was launched by The Nature Conservancy (TNC) in collaboration with key partners, including: Zhubo-AAO; Glocal Estate Management; and Urban Planning & Design Institute of Shenzhen (UPDIS) [1]. Located on an old building in Gangxia village in Shenzhen, the project utilizes three-dimensional light steel structures that are simple to construct and have the capacity to hold over 420 plant containers, filled with plants mostly native to Southern China [1, 2]. The original concrete rooftop is transformed by vegetation, which is capable of absorbing and preserving rainwater, creating a nature-based stormwater management system for the residential building, achieving a 65% of run-off control rate [1, 2]. As a result, a living “green cloud” is formed on a rooftop of Gangxia village, showcasing “a model to improve the urban village’s stormwater management system and its living environment” [1. p.33].

In 2019 at the Gullele Botanical Garden in Addis Ababa, the Ethiopian government launched a historic tree planting campaign. Over 350 million trees were planted in an ambitious move to counter the effects of deforestation and climate change. The Gullele Botanical Garden was selected as one of the 1000 sites all over the country involved in the Green Legacy Initiative, a national campaign against the effects of climate change. The United Nations estimates that Ethiopia’s forest coverage has declined drastically to a low of just 4 per cent in the 2000s from 35 per cent a century earlier. (1,2) The Botanical Garden was not selected aleatory as it is Ethiopia's only botanical garden and it is a nursery for various indigenous plant species. Its mission is to conserve and promote the Ethiopian diverse plants and tree population and it is a conservation initiative located at the northwestern tip of the Addis Ababa City Administration. The site covers an area of 1000 ha which is representative of the central plateau of Ethiopia. (3)

The Krubong landfill site has been proposed to undergo a "thorough and safe environmental rehabilitation program[me]" so that the site can be developed as a public park (Ref. 1). Following completion of a feasibility study, it is envisaged that significant rehabilitation work to address environmental degradation and restoration of natural habitats will be required, after which the site will be developed into a public park (Ref. 1). The programme remains in its planning stage, but seeks to address Sustainable Development Goals (SGDs) 11.6 and 15.1 through protecting, restoring and promoting sustainable use of ecosystems and reversing land degradation and/or biodiversity loss; and reducing the environmental impact of cities by paying special attention to waste management and providing access to safe, open public spaces (Ref. 1). At a more local level, the programme intends to complement additional programmes laid out in Melaka's Resilience strategy document, including promoting both cycling and pedestrian networks and reshaping public spaces in the city (Ref. 1).

Santalaia is a high-end, multi-family residential building located in the heart of downtown Bogota, Colombia. Santalaia is often referred to as "the green heart of Bogota" and is seen as an icon of sustainability [1]. The 11-story building was completed in 2015 and all eleven floors are engulfed in many species of plant wildlife to encourage biodiversity. There are 115,000 native plants of 10 different species covering a total area of 3117 m² [2,3].
The plants included on the exterior of the building rely on a hydroponic system and provide a model of how to increase green zones in urban areas. A vertical garden of this size provides natural beauty in the middle of concrete Bogota while mitigating the carbon footprint of more than 700 people. An additional benefit of Santalaia’s vertical garden is that the plants create a “green carpet” that serve as insulation and reduce the use of air conditioners, an increasingly valuable contribution during times of rising temperatures due to climate change [5,6].

The Wuqing District of Tianjin is a rapidly developing suburban district, northwest of the city core, containing 4 larger 5 smaller rivers, 5 water reservoirs, Wetland area that partially protected by the DaHuangPu Nature Reserve, the Jinbei Forest Park, several public parks, greenery near buildings, green roofs and vegetation along roads. A spike in population growth going from 130.000 in 2000 to 1.2 million in 2018 brought the need for wide urban development where the district focused on implementing blue and green infrastructures (1). "The urbanized area of the district is reported to meet the requirements of the national ‘Garden City’ standard with over 36% green coverage, currently aiming to achieve 45% on the long run, and was selected as a pilot national ecological demonstration area for green urban development in 2014. Since 2014, over 500 million EUR was invested into blue and green infrastructure projects (1 p26). The three flagship projects evaluated here are 1) the South Lake (Nanhu) Area that combines business, recreational, residential, and ecological development around in a waterside area, 2) the North Canal Suburban Park which is a recreational, entertainment and wetland area on 2.53 km2 where over 72.000 trees were planted in recent years, 3) and the 400 meter wide, multi-functional green corridor running along the Cuiheng Road (1).

The project is part of a bigger initiative aimed at restoring the coastal forest near the city of Mahajanga in western Madagascar. Alongside 2 international NGOs, the community located in the bay next to the city of Mahajanga implemented the intervention with the ultimate goal being to transition the land into a protected area as part of the greater "Mahajanga Green Belt Project". The regrowing forest will form the northwestern end of the greater Mahajanga Green Belt, with the southeast meets the Ankarafantsika National Park. The project also has a gendered aspect as it aimed to employ mostly the women in the suburbs of the city. (1,3)

Xalapa is located beneath towering volcanic peaks in the Sierra Madre Oriental, and the city is crossed by at least five minor streams, seven rivers, and it has four man-made lakes and one lagoon in its territory. Its natural ecosystem represents “1% of the national forest area and hosts more than 12% of forest biodiversity” [1]. However, unplanned expansion has resulted in deforestation and the inadequate management of its waterways. In addition, forests, riparian corridors and wetlands have been cleared for agriculture and urban infrastructure. These disruptions to the environment have increased the frequency and intensity of flooding in the city [2]. To meet the environmental challenges, the United Nations Environment Programme (UNEP) and Mexico's Secretariat of Environment and Natural Resources-SEMARNAT launched an initiative as part of UNEP's multi-city CityAdapt Project, backed by the Global Environment Facility (GEF) [3]. The project focuses on four interventions to improve resilience to climate change through NbS: 1) riparian restoration along the Papas urban river; 2) ecological restoration of the Estropajo Hill; 3) installation of rainwater systems within the most vulnerable areas in Xalapa; and 4) implementation of an artificial wetland at schools [2,4].

A greening project in Laval aimed to replace impermeable surfaces such as asphalt with vegetation. This process would allow water to infiltrate the soil on a surface area of 3000 square meters and plant 7200 plants on land located near or inside urban heat island zones of the city (Ref. 1,2,3,7). The project takes an integrated approach to mitigate the impact of urban heat islands, which make up 12-13% of the territory in Laval (Ref. 1,7). Particular focus of this project is placed on planting on sites of vulnerable communities (Ref. 1,3).

The Ecological Wetland Park is a 630,000 m2 artificial wetland located in a high tech industrial pioneer zone, adjacent to the Tianjin Harbor. The project was initiated by an agency of the local government and constructed with financial support from the Asian Development Bank (1). The area of the park used to be "a natural coastal salt marsh, which become reclaimed land in the early 2000s. The resulting saline-alkaline area had minimal ecosystem value and use value (as it was not considered to be suitable for agricultural activities either)" (1 p20). The wetland park's objective is threefold: 1) to provide a natural wastewater treatment plant for the industrial area to decrease pollutant discharge into the Bohai Bay and improve water quality; 2) to rehabilitating and restoring the once thriving biodiversity in the Harbor Area and the Hai river's estuary 3) to create a place for recreation and leisure for residents. (1)

The green belt was created not only as an aesthetic element but also to serve as the lungs of the city. The forest planting works around Nur-Sultan have been carried out since 1997 [6, 7]. The area of ​​the green belt of Nur-Sultan is 100 thousand hectares, of which 15 thousand hectares are planted within the city limits. The main idea of the project was to provide comfortable conditions for the residents of Nur-Sultan city, which would serve as a mechanism for improving air quality, mitigating climate and as a natural barrier to protect the city from dust winds and snowstorms [2, 4, 5, 6, 7]. An important aspect that was taken into consideration are the animal species of the forest, as the territory of the green belt is inhabited by foxes, hares, corsacs, white and grey partridges, roe deer, wild boars, etc [1, 2, 7, 8]. The primary importance of biodiversity efforts is assigned to the breeding of birds, especially pheasants [1, 2, 3, 4, 5], as pheasants are an element of local cultural heritage, and on the territory of the green belt, traditions and cultural events related with the pheasants are organised every year [2, 4]. The young forest should turn into an improved recreation area, a favourite pastime for city residents at any time of the year [2,7].