Technological

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].

Hatirjheel area development project is a wetland restoration project that explores the possibility of reintroducing water edge elements into the city of Dhaka. The project includes both engineered infrastructure and NbS. The restored jheel (wetland) and Begunbari khal have improved storm-water management of Dhaka and made aquatic biodiversity better. It also increased green and open space in the busy capital. The intended objective of the project was to create a bridge between the densely developed old part of the city on the south and the new organised north part of the city. Spreading over 311 acres, this project has endeavoured towards improving connectivity between major urban corridors as well as acting as a retention pond to mitigate the flash flood-prone densely populated part of the area. [1,2]

The redevelopment of the Bishan-Ang Mo Kio Park (Singapore) saw the naturalisation of the previously channelised Kallang River, as well as the installation of wetland cells as water cleansing biotopes and creation of butterfly habitats (Ref. 1).

The Kallang River was previously confined to a concrete canal that ran to the southern edges of Bishan-Ang Mo Kio Park (Ref. 1). The channel segregated the two residential areas situated on either side of the park, with the river's 2.7km continuous concrete channel being crossable at only certain defined points (Ref. 3). Following its naturalisation, culminating in 2012, the now 3.2km meandering river is considered the park's highlight, "merg[ing] seamlessly with the park's greenery" (Refs. 1 & 6), and creating a "blue-green recreational network which is well-integrated with nearby residential areas" (Ref. 2).

This intervention was initiated in 2014 in Agege, a slum and a city in itself belonging to Lagos. Agege is one of the 7th most populated low-income communities in Lagos with a total population of around 1,033,064 people. Climate change in Nigeria led to seasonal droughts and floods, causing pressures in terms of food security as well as high temperature and humidity levels which affect directly the economically disadvantaged population in the slums of Lagos. In 2014 a research team at the University of Cardiff alongside community leaders of a Yoruba community in Agege implemented a study on vertical gardens in residential areas with the purpose of alleviating local temperatures and enhancing biodiversity. The implementation started with a study and was continued with the introduction of practical gardens maintained by the local community of 3 residential buildings (one in Suru Street, another in Lagos Street in Agege, and a third in Abeokuta Street). (1,2,3,4)

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 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)

Quelimane is a port city in Mozambique. It lies below sea level right alongside the Good Signs river (Rio Bons Sinais), and just a few kilometres from the coast. The frequent extreme weather phenomena such as rain and marine flooding render the city extremely vulnerable to climate risks. In 2013, the municipality concluded that one solution involves restoring large areas of mangroves, which act as a nature-based solution against flooding, helping to stem the tide by preventing soil erosion. In the past mangroves were cut down by the locals for building and cooking but now with the help of the municipality and local communities, the trees are restored and used as the first line of defence against climate change (1).

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].

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)