Singapore’s land scarcity and high population density necessitates innovative land-sharing solutions to incorporate nature in infrastructure and service the city’s needs. Reducing the environmental impact of roads has proven particularly challenging, as they fragment habitats and require engineered materials (e.g. concrete) to provide safe passage for vehicles. Although the land used for roads can be minimized, important road networks face challenges in integrating nature within their design. In response, Singapore has developed a system of roads called “Nature Ways” that feature native trees and shrubs. Singapore’s National Parks Board has drawn key lessons from native tropical forests to successfully incorporate a diverse range of species alongside verges. By emulating the multiple layers of the forest ecosystem in multi-tiered tree planting systems, the Nature Ways mimic the structure of the rainforest. They create vibrant, natural niches for small mammals, birds, reptiles, amphibians and insects, providing ecological connectivity between green spaces across the city. A denser tree canopy helps to reduce ambient temperatures and curtail the urban heat island effect, as well as absorbing carbon and air pollution, retaining soil moisture and intercepting heavy rainfall, thereby lowering flood risk. The Nature Ways also improve the travel experience across the island for commuters, pedestrians and cyclists. Despite being one of the world’s most densely populated cities, thanks to its Nature Ways, Singapore is now the second-ranked city on Treepedia’s global Green View Index – a tool developed by MIT’s Senseable City Lab that measures tree canopy cover in cities.
The Plaça de les Glòries Catalanes, traced in the nineteenth century by the engineer and urbanist Ildefons Cerdà, was supposed to become the heart of “the new Barcelona”. But this square, located at the intersection of three of the city’s main avenues – the Diagonal, the Meridian and the Gran Via de les Corts Catalanes -, became a major metropolitan traffic infrastructure. In February 2013, and with the aim of transforming this 13-hectare urban space and putting an end to the square's character as a road junction, the Barcelona City Council launched an international competition called: Free Space of Plaça de les Glòries Catalanes. The winner project, called «Canopià urbana» (Urban Canopy), became a new genre of land sparing in Barcelona, even beyond the plaça. The plaça is surrounded by a broader intervention of about 70,000 m² including new buildings and a renewed urban experience prioritizing biodiversity and climatic comfort, as well as space for everyday recreational activities. The former traffic node has been repurposed in its three layers: (i) The subsoil, currently occupied by hard infrastructures, converted on a fertile living place allowing the multiplication of biotopes; (ii) The soil, converted on a flat and multi-purpose walkable space varying from grey to green; (iii) The tree canopy, including city’s roofs, densified and contributing to ecological continuity between Sagrera and Ciutadella neighbourhoods, as well to as climate regulation. All three layers contribute to efficient water management. Rainwater is recovered from the site and from the roofs. The plaça is re-built with native vegetation with low water needs and well adapted to the climate - 70% native and 30% exotic. The new fertile soil, together with the density of plants in all plant strata (herbaceous, shrubs and trees), ensures the necessary conditions for the establishment of a diversity of species (temperature, humidity, light and nutrients).
Current food production systems require a fundamental transformation in the face of population growth, climate change, and biodiversity loss. Synecoculture, a novel method developed by Sony Computer Science Laboratories, Inc. believes that food systems’ environmental impact can be redressed by the same advanced social systems that have proven capable of producing food at scale. The project seeks to build networks of augmented ecosystems in cities, which means creating green urban spaces with high diversity and functionality that sustain both human and ecological health. The method has been implemented in cities like Tokyo, where than 200 edible plant species have been introduced allowing a self-organizing process of soil microbial life across the urban landscape. Synecoculture shifts green areas into food production nodes, turning a small-scale activity into complex biological interactions. Human activities actively intervene to achieve biodiversity and ecosystem functions beyond the natural state and, without the use of any fertilizers or agricultural chemicals, species of useful plants grow together in a dense mixture by utilizing the self-organizing power of the ecosystem. Synecoculture and augmented ecosystems are more effective in environments where conventional monoculture is difficult, such as dense urban areas. In addition to food production and greening, augmented ecosystems are also expected to provide solutions to problems such as job creation, improved nutrition and increased public safety. Rich biological interactions in ecosystems is known to stimulate the expression of secondary metabolites of plants (abundant in wild foods) that act as health-protective bioactive compounds in humans. Recent studies have suggested that modern urban lifestyles cause an increase in immune- related anomalies such as allergy, diabetes, cancers, and neurodegenerative diseases, through reduced diversity of the human gut microbiota. Such global increases in chronic diseases impose medical burdens and asset freezes, producing significant economic losses that rise up to half of the national expenditure in developed countries. Synecoculture is committed to improving all forms of life and is creating an educational platform to enhance ecological literacy to enrich biodiversity and human health through urban agriculture.
As part of the development of the city of Barranquilla in 2020, the Integral Recovery Plan for the “Ciénaga de Mallorquín” (Mallorquín Swamp) covers an area of 2,250 km2, located at the northern end of Barranquilla, in the mouth of the Magdalena River. It has been proposed as a response to climate change and the urgent need to restore this degraded ecosystem, while opening up a space for public recreation and enhanced encounters with nature. The Mallorquín Swamp is of vital importance not only for the (re)integration of nature in the city, but also as a starting point for a resilient and green recovery after the pandemic. The swamp is highly polluted as it became the dumping area of two undeserved sectors of Barranquilla. It also suffers from erosion and sedimentation caused by the informal and uncontrolled settlement on its banks. This Master Plan will have indirect impact on 1.206.000 citizens and direct impact on 20,500 local inhabitants of two main districts, improving air and water quality, boosting a sense of belonging, and developing new job opportunities based on increased tourism and construction and restoration activities. It will be deployed through six projects: (i) Ecopark Family District, (ii) Recovery of the Puerto Mocho Beach, (iii) Urban renewal of Las Flores and La Playa districts, (iv) Ecological restoration of the water body, (v) Las Flores and La Playa Green Belts, (vi) Las Flores and Puerto Mocho Beach connectivity. The total investment is $140M USD, and up to $1.48 billion are expected to be mobilized over the next 10 years.
Intensive rainfall over three consecutive days in 2017 triggered a major landslide above the city of Freetown, Sierra Leone, which destroyed hundreds of buildings in the city, killing 1,141 people and leaving more than 3,000 people homeless. The post-disaster recovery focused not just on earthworks to prevent future landslides but involved a nature-based landslide and flood risk management strategy which included the planting of 21,000 native trees by residents trained in forestry by the UN Office for Project Services (UNOPS). This programme helped to stabilize the slopes and reduced rainfall runoff that could lead to flooding. As extreme weather patterns brought delayed rains, abnormally heavy rainfall and urban expansion, the Mayor of Freetown also ran a “Freetown the Treetown” tree planting campaign to increase vegetation cover by 50% by the end of 2022. This initiative is part of the capital’s three-year strategy “Transform Freetown” (2019-2022), which aims to enhance the productivity, liveability and resilience of the city through urban greening, resilient infrastructure and improved governance. To cultivate a sense of community ownership over the campaign, the trees’ growth is tracked by a community-based team using a “Treetracker” smartphone app; a unique geotagged record is created for every new tree. Locals who plant the trees make periodic visits to ensure that they are growing well and document their status on the app, in return for mobile micropayments. As part of this campaign,15 different species of trees were nursed on 11 sites across Freetown. By the end of 2020, more than 245,000 trees had been planted, covering 35 wards and engaging 300 communities, 76 schools, 11 health facilities and 66 religious institutions.
The Cheonggyecheon river restoration project focussed on revitalizing the Cheonggyecheon Stream, a waterway that had been covered by a highway overpass for decades. An elevated freeway and concrete deck covering the stream was ageing and posed safety risks. The public avoided the area under the freeway due to criminal activity and illegal waste dumping, and the freeway itself was always congested, posing pollution issues. Initially, transport experts were concerned that removing the elevated highway would increase congestion in the northern part of the city, since it carried around 170,000 vehicles per day. The Seoul Metropolitan Government chose to dismantle the elevated freeway and concrete deck and, to improve north-south linkages, proposed that 22 bridges – including 12 pedestrian bridges and 10 for automobiles and pedestrians – would be built to connect the two sides of the Cheonggyecheon Stream. To reduce congestion, car use was discouraged in the city centre, rapid bus services were introduced, and improved loading and unloading systems were implemented. Innovative governance and interagency coordination were critical to the process, as was extensive engagement with local communities, research groups and public-private players. Close to 4,000 meetings were held with residents and a programme was developed to encourage involvement, resulting in 20,000 participants. After the restoration of the Cheonggyecheon Stream, land value in the adjacent area increased between 25% and 50%. The project served as a catalyst for an estimated KRW 22 trillion (South Korean won - or $1.98 billion) worth of capital investment in redevelopment that would not have otherwise been invested. The project secured flood protection, increased overall biodiversity by 639% (between 2003 and the end of 2008), reduced the urban heat island effect and lowered small-particle air pollution by 35%. The redeveloped area now attracts an average of 64,000 visitors a day, including foreign tourists who contribute up to KRW 2.1 billion ($1.9 million) to Seoul’s economy.
The City of Stockholm became the first European Green Capital in 2010. As early as 1976, the city adopted its first comprehensive environment programme. Continuing with this role model, the city launched in 2020 its new Environment Programme 2020–2023 supporting environmental and climate commitments that will lay the foundation for creating a city with a high quality of life for Stockholmers. Stockholm is a fast-growing city with more than 200,000 new citizens and 100,000 new homes expected by 2030. Eight out of ten Stockholmers feel the city should place even higher demands on citizens to live in a nature-positive way, and they want it to be easy to choose environmentally friendly solutions. In this context, the City of Stockholm is integrating biodiversity in a systematic and holistic approach in all new urban areas, as well as working with existing city districts. Such is the case of the Stockholm Royal Seaport, a fossil fuel-free district by 2030 where ecosystem services and biodiversity are integrated through one main premise: “Let nature do the work”. Through intelligent design, blue and green structures are fulfilling multiple functions. Green roofs, ‘ecoducts’ and water collection systems offer opportunities in terms of attractiveness values and recreation that contribute to improved, competitiveness, health and wellbeing. To date, 93% property developers fulfil the Green Space Index, a total of 137,432m² green spaces – including 26,400m² of green roofs and 47,300m² of courtyards - have been created, and 100% of dwellings have access to park and nature areas within 200 metres. The local climate is improved, and the effects of coming climate change reduced; meanwhile biodiversity increases, and dispersal zones are strengthened, making the city more resilient to future challenges. Furthermore, community participation and food cultivation at scale in the area is contributing to local food production. The project Stockholm Royal Seaport has received the Swedish Landscape Architecture Prize in 2019.
60% of Costa Rica’s population lives in the Greater Metropolitan Area (GAM), which constitutes just 4% of the national territory. Curridabat, one of the GAM’s main urban centres, stands out for its multidimensional government plan - developed in 2015 under the name “Ciudad Dulce” (Sweet City) - and for being one of the first cities to create a series of Urban Natural Parks (PANU), a new protected area category issued in February 2021. Despite having significant environment protection afforded for nine other protected area categories, urban forests have not historically been protected by the country’s National System of Conservation Areas (SINAC). Driven by Curridabat’s municipality, Ciudad Dulce’s development model is based on five dimensions: biodiversity, habitat, infrastructure, coexistence and productivity. Curridabat treats green spaces as places within its urban infrastructure where all forms of life can coexist and productivity is constantly ensured. Pollinators, diverse plant species and people thrive in urban gardens and parks, producing fruits and vegetables, and promoting soil regeneration, leisure, tourism and cleaner air. New green areas are also being created to meet the needs of vulnerable plant and animal species through improved connectivity and habitat restoration. City officials claim that the greatest achievements of Ciudad Dulce can be found in neighbourhood wellbeing. Air quality and the diversity of species and green spaces aren’t the only improved aspects; peoples’ spirits have also lifted thanks to increased participation, intergenerational and multistakeholder collaboration, and community activities. This biophilic approach has earned the city several awards, including “Best City Plan” from the Congress of New Urbanism (CNU), the “Wellbeing Cities Award” from New Cities, and the “Guangzhou International Award for Urban Innovation”.
The municipality of Villavicencio in Colombia has shown strong leadership and commitment to maintaining its urban wetlands through multisectoral governance. In 2017, the conservation, restoration, management and sustainable use of urban wetlands became a joint task, carried out by national and local governments, communities, organizations, academia and the private sector. In 2020, the municipality responded positively to citizen advocacy by officially recognizing the Interinstitutional Committee for the Protection of Urban Wetlands, together with a new legal act that emphasized the importance of coordination at multiple levels for the effective protection of these urban ecosystems. Further incentives for the conservation of urban wetlands have since been put in place, in recognition of the ecosystems’ social, cultural, economic and ecological value. In 2021, a second decree was established to reduce land conversion pressure on urban wetlands; in exchange for increasing the height and density allowances of the current owners’ housing development projects, Villavicencio’s government sought to regain land ownership. The licences were issued for suitable residential districts in alternative parts of the city and included rights for urban developers to increase social housing units. As a result, over 44,000 hectares of wetlands will be regained, more than 400,000 square metres of new building areas will be granted, and over 20,000 housing units will be created.
Since the 1970s, Kenyan forests on steep hillsides and in wetlands have been converted for agriculture, removing natural areas for storing run-off and accelerating the sedimentation of rivers. The Tana River watershed, which supplies 95% of the water for Nairobi’s four million residents and another five million people living in the river’s catchment, has been subject to this type of land-use change. Due to changes in the hydrological cycle brought about by conversion, 60% of Nairobi’s residents now lack access to a reliable water supply. In response, the Upper Tana-Nairobi Water Fund was created in 2015 to provide a secure source of water and conserve the watershed. A public-private steering committee was established, bringing together diverse stakeholders, including major utility companies, the Water Resources Management Authority and the Tana and Athi Rivers Development Authority, as well as prominent corporations. Contributors to the Fund include downstream users and upstream stewards, such as agricultural landholders and development organizations. Finances are used to promote sustainable land management practices, including strategic tree planting and land terracing to filter and regulate water supply to the river’s watershed. Funds are also used to distribute water-saving technologies for agricultural use, boosting productivity and generating cost savings. The Fund’s activities now provide “several million more” litres of water to Nairobi each day. Furthermore, project monitoring revealed a 15% decrease in sedimentation, with Nairobi’s water supply achieving World Health Organization turbidity standards for the first time in 2016. It has been estimated that an investment of $10 million in the Water Fund will return $21.5 million in economic benefits over 30 years
Carbon credits are part of the effort to keep cities green and equitable. The non-profit carbon registry, City Forest Credits, has developed Carbon+ Credits for city forests by working with scientists, urban forest professionals and carbon industry experts to develop credit issuing standards. The standards include rules for eligibility, ownership, quantification, monitoring, verification and issuance of Carbon+ Credits that quantify not just CO2 , but stormwater reductions, air quality impacts and energy savings. Increasing tree cover in cities not only has a quantified positive environmental impact, but also brings social and economic benefits through youth engagement, new workforces and nature enhancement in under-resourced neighbourhoods. In addition, it provides a way for the private sector to contribute to green, healthy and more equitable cities. Carbon and sustainability leaders such as Microsoft, PayPal, Bank of America, Jonathan Rose Companies and Cloverly have purchased or funded urban forest credits and projects. Carbon programmes are now underway in 16 cities across the United States and the country’s city forests provide $18.3 billion in benefits per year. This value is expected to grow if urban areas continue to embrace City Forest Credits’ funding opportunities and expand their tree cover
Mexico’s Yucatan Peninsula is home to the Mesoamerican Barrier Reef System that stretches 1,000 km – the longest in the Western hemisphere and second only to the Great Barrier Reef. It is home to some of the world’s most unique coral reefs, mangrove forests, fish species and marine mammals, and also protects Riviera Maya - Mexico’s primary tourism hub, which supports economic growth in the regions’ towns and cities. However, this ecosystem is under severe threat from disease, bleaching, algae overgrowth and, most importantly, hurricanes, which have become ever-more present as a result of climate change. A category 4 or 5 hurricane can destroy up to 60% of live coral cover and significantly reduce the resilience of built areas along the reef corridor. In 2018, Swiss Re collaborated with The Nature Conservancy (TNC) and regional governments in Mexico to help protect against reef damage in the Mesoamerican Barrier Reef System by creating a new “parametric” insurance solution. The insurance product provides rapid payouts to fund essential reef restoration measures following strong hurricanes. Premium payments come from the Coastal Zone Management Trust, set up by the state government of Quintana Roo, with support from TNC. The Trust collects funds from tourism taxes and other government sources that benefit from the reef’s protection. By combining private capital with public resources to fund insurance, regional governments can plan more consciously to protect the reef system