In recent years, an increasing number of cities have actively moved towards greener urban ecosystems and more improved environmental stewardship. According to the UN Habitat, who are a branch of the United Nations which promote sustainable and transformative development in urban areas, cities consume 78%[1] of the world’s energy and produce more than 60%[2] of greenhouse gas emissions, with 60% of the world’s population expected to be living in urban areas by 2030. In an attempt to reduce their monumental environmental impact, cities all over the world such as Oslo and Auckland are harnessing green technology to accelerate the reduction of carbon emissions released by urban areas.

Urban greening, which is the process of increasing green spaces in urban areas, has become a popular strategy utilised by city planners when focusing on increasing environmental sustainability. As cities expand beyond the rural-urban fringe, green field sites are often damaged. This reduces the effectiveness of carbon capture and storage by plants and hence reduces climate change mitigation. 37.6% of Auckland is covered by a forest, a figure that has grown by 6% since 1990.  Similarly, New York’s Central Park, which covers 843 acres, acts as what some call the ‘lungs of the city’. Green spaces in urban areas reduce the phenomenon known as the Urban Heat Island Effect, which is when buildings roads and other infrastructure absorb and re-emit the sun’s heat more than natural landscapes. This can result in a temperature that is 3-4 degrees higher than the surrounding countryside. Greenery on the roofs of buildings reduces the surface temperature and serves as insulation for the structures, which reduces the energy needed to heat and cool the buildings. For example, architects in Milan have built the ‘Vertical Forest’ which has aimed at regenerating declining urban biodiversity whilst expanding the city. The Vertical Forest hosts 900 trees and 20,000 plants, distributed according to the sun exposure of the façade. The Vertical Forest helps to build a micro-climate which filters dust particles. Most importantly, the Vertical Forest acts as a large carbon sink, which significantly reduces the concentration of carbon dioxide in the atmosphere and produces oxygen.

Both images above show the vertical forest in Milan. Credit: We Build Value[3]

Sustainable urban living leads the way for biodiversity in the built environment. London is an example of enhancing biodiversity through nature-friendly infrastructure. London has bird boxes, bat boxes, and insect hotels in order to create more habitats for wildlife. Biodiversity has been incorporated into London’s urban planning; it has set a target to increase the cover of green spaces by 5%[4] by 2030. This urban greening involves planting more trees and creating more green spaces. Singapore is also a world leading city for biodiversity in the built environment. Singapore’s aim for promoting biodiversity is through further urban greening; like Milan, Singapore has incorporated vertical forests as well as roof top gardens. A notable place is Singapore’s Gardens by the Bay which contains giant tree-like structures which creates more natural habitats for wildlife and therefore results in Singapore being very bio-diversly rich.

The transition to more sustainable forms of transport has been accelerated by several cities such as Oslo and London in recent years. London has been at the forefront on sustainable transport initiatives, a notable aspect being its widespread adoption of hybrid and electric buses. More than £300 million has been spent in transitioning the London bus fleet to low-emission alternatives. Recently, Hydrogen powered buses and hybrid buses have been introduced to improve fuel efficiency and minimize the environmental impact by drastically reducing the level of carbon emissions. Following this, London began to deploy fully electric buses, creating a cleaner and quieter urban transport system. Each of London’s zero emission buses reduces Carbon emissions by 70%.[5] The emissions released during manufacturing and charging of the buses mean that the overall carbon footprint of these buses is not zero, however the carbon emissions are significantly lower than the previous diesel-powered buses. Moreover, London’s extensive underground rail network (the Tube) is an essential part of London’s environmentally sustainable transport infrastructure. The Tube’s extensive coverage across the whole of London reduces reliance on road vehicles and therefore reduces traffic congestion. This therefore results in a reduction in carbon emissions and an overall improved air quality in the city. In addition, London has continued to expand its rail network with the brand new ‘Elizabeth Line’ opening in 2022 spanning from the East to the West. The Elizabeth line is expected to save between 70,000 and 225,000[6] tonnes of CO2 every year. The carbon emissions generated from the project is estimated to be close to 1.7 million tonnes therefore it could take 7-24 years for the project to start reducing carbon emissions. The Elizabeth line project is part of TFL’s aims to be fully carbon neutral in its operations by 2030[7].

Across the world, governments are trying to incentivise people to purchase electric cars largely to reduce the significant volume of carbon emissions released owing to urban congestion. The Norwegian government encourages the purchase of electric cars in cities such as Oslo through tax benefits. EVs are exempt from VAT and Norway’s high purchase tax on new vehicles. The Norwegian government has a national goal that all new cars sold by 2025 should be zero-emission vehicles (electric or hydrogen). By the end of 2022, over one third of registered cars in Oslo were battery electric.

The American government have implemented the Inflation Reduction Act which has resulted in certain electric vehicles qualifying for a tax credit of up to $7,500. This has significantly boosted the purchase of electric cars across cities in the USA. New York currently has an estimated 158,000 electric vehicles with that number expected to increase tenfold by 2030.

The German government committed €2.5 billion for investment in EV infrastructure and a €9,000 subsidy per vehicle to encourage the transition to EVs. By the end of 2022, 52% of new vehicle registrations in Berlin were electric cars.

EVs, however, are not entirely the goldilocks form of transport to eliminate carbon emissions. EV batteries consist of rare-earth metals such as nickel, lithium and cobalt. Mining for these materials are very energy intensive processes which therefore results in the release of large volumes of carbon emissions. The mining industry also poses a significant threat to ecosystems as there is the potential for the monumental destruction of ecosystems which may catastrophically impact biodiversity. The supply of electricity to EV chargers come, in a large proportion of cases, from fossil fuel power plants. Therefore, the increase in the number of EVs may increase the demand for electricity from these fossil fuel sources therefore resulting in increased carbon emissions.

Energy policies are a huge determinant of global carbon emissions. Governments which focus more on investment into renewable energy schemes such as offshore wind in the UK, are likely to reduce carbon emissions significantly owing to the reduction in the release of greenhouse gases. Norway is known as a renewable energy superpower with 98% of electricity production coming from renewable energy sources. Hydropower is the source of most of the electricity production owing to Norway’s maritime climate which has large volumes of precipitation and inflows into the dams and reservoirs. Norway has also unveiled plans for a major expansion of its offshore wind energy production by 2040; the Norwegian government has earmarked two areas in the North Sea to accommodate up the offshore wind farms. Most homes in Norway are now equipped with smart meters allowing the harvesting and storage of solar energy. Consumers are even able to sell back excess energy to energy companies which acts as a massive consumer incentive. Owing to the rapid growth in the green sector, innovative solar technologies for solar panels have been set up; The start-up Ocean Sun has pioneered a solar farm that floats on the surface of the ocean.

This dramatically increases the potential for solar energy generation particularly in densely populated environments.

Ocean Sun is one of many corporations trying to expand this technology throughout Norway. This concept was initially tested in Oslo in May 2022. Similarly, the village of Furumogrenda in Oslo makes excess energy from solar power resulting in the village selling some of their energy back to the Norwegian national grid. Furumogrenda is one of many energy independent villages in Oslo.

The village of Furumogrenda
Credit: Forbes

Overall, the Urban Green Revolution is not merely an urban development transition but a necessity for our planet’s survival. Cities across the world are adopting green policies, with different cities acting as world leaders for different urban environmental sustainability aims. Sustainable cities boost innovation in the green sector allowing for the effective mitigation of climate change and therefore leading to a more environmentally sustainable future.








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