Circular cities - A way forward for building sustainable and climate-resilient future cities of Asia

Article released on May 25, 2021 Originally on LinkedIn platform

Over the past few years, societies have undergone tremendous transformations due to rapid urbanization. Cities occupy a relatively small fraction of the Earth’s land area but serve as habitats for more than half of the human race (Parés-Ramos et al., 2013). Cities are the highest form of human interaction. Therefore, cities are increasingly becoming important as they act as catalysts of social, economic, cultural, and ecological change. They have attracted many people by providing employment opportunities, housing, education, and health care, being major cultural centers, centers of innovation, and provision of economic activities.

Rapid urbanization in many developing countries has resulted in uncontrolled urban growth (UN-Habitat, 2016). Uncontrolled urban expansion has been known to cause environmental degradation and social tension thereby threatening resilient and sustainable developments of cities. At the same time, the climate of our planet is changing rapidly both at the global and local scales. Cities are being continuously confronted with disasters such as floods, earthquakes, landslides, storms, and other extreme weather events. Climate change affects the intensity, magnitude, and spread of hazards whereas urban expansion increases population exposure to hazards. Therefore, systematic and contemporary strategies to build climate-resilient and sustainable cities should be developed.

In terms of geographical area and population, Asia is the largest of the world’s five continents with over 50 countries. It covers approximately 45 million square kilometers and accounts for nearly 30% of the earth’s land area. It has a population of 4.6 billion people, contributing to about 58% of the world’s population as of 2021. With urbanization becoming a global phenomenon, especially in African and Asian countries, it is projected that by 2050, more than 66% of the world’s population will reside in cities, with 90% of that increase occurring in these two continents alone. Asia will be home to around 3.3 billion urban residents by 2050 which is almost two-thirds of the world’s urban population (Dulal, 2019). The below image shows the persistent issues and emerging urban challenges due to the increasing urban population.

In the West, where the largest metropolises barely exceed 10 million inhabitants, Asia’s megacities have already reached a scale that is unparalleled. It is estimated that the number of megacities in Asia will further increase with 21 out of 37 megacities around the world being in the Asian region by 2025 (Dulal, 2019).

Already the scale of greenhouse gas emissions in Asia is similar to that of developed economies from the west. If we don’t plan the Asian cities of tomorrow in a sustainable way the impacts of climate change across the world would be devastating as cities are responsible for more than 70% of global carbon dioxide emissions (UN-Habitat, 2016). Asia should take inspiration but not follow the footprints of western countries in advancing their cities or in urbanization patterns as Asia is significantly different from western cities in terms of geographical and climatic contexts, culture and heritage, living style, density, land use mixes, travel behavior, policies, governance, and institutional capacities.

Asia has to build its own unique cities embracing its culture, heritage, societal values while being climate-resilient and sustainable.

Asian cities have been compact with high densities with mixed land-use patterns for a long time. While dense cities offer some advantages like efficient land use, shorter commutes, better access to services, and preservation of green space outside the urban centers, they also have many negative effects, especially for the low-income groups (Cheshmehzangi & Butters, 2016). The influx of millions of new city inhabitants, combined with poor urban planning and a lack of appropriate policy instruments, put enormous pressure on land use, density, safety, resources, resilience, and sustainability. As a result, urbanization patterns in Asian cities are very diverse and uneven, with sprawl, congestion, environmental degradation, fiscal pressures, unemployment, and informal settlements developing in both peri-urban and urban areas.

One of the main disadvantages observed due to the high-density pattern in many Asian cities is the reducing affordability of living space. To accommodate the massive influx of residents, cities began vertical growth with high-rise buildings and massive residential complexes, encroaching on the city’s small green spaces, and resulting in concrete jungles. The skyrocketing prices of living spaces, combined with issues such as pollution, fire hazards, inadequate parking spaces, lack of green spaces, poor sound insulation, and a lack of adequate public facilities, drove many people out of cities, especially to the fringes. People with insufficient financial resources began to settle on the fringes and in informal settlements, resulting in sprawl and urban fragmentation. Urban sprawl is further being fuelled by demographic shifts such as aging population, volatile economic growth, unemployment, low-wage low-skilled jobs, income inequality, social polarization, and segregation (United Nations, 2019).

Most green spaces within cities were lost due to poor land-use planning and lack of proper land management policies, resulting in severe environmental and health issues.

Delhi, India’s capital, is an example of a city where residents are struggling to find clean air to breathe.

Globally, achieving sustainable development has been the goal of every country. Sustainable development as defined in the Brundtland Commission report in 1987 is the development

“that meets the needs of the present without compromising the ability of future generations to meet their own needs”

We humans have historically taken a straightforward approach to the consumption of various assets and products. Basically, we consume them for a certain amount of time and then discard them, causing them to go to waste. As a result, the solution is linear, resulting in linear cities. However, considering the vast amounts of assets and products we consume, this is not a sustainable approach for cities, since we continue to pile items in landfills while having negative environmental consequences. As a result, waste disposed of in landfills and incinerators today contributes significantly to the city’s air pollution and greenhouse gas emissions. The alternative to this linear approach is the new concept in urban sustainability, which is circular cities.

It is accomplished by consuming assets and products responsibly and feeding back the consumed assets and products back into the economical, societal, and environmental activities (United Nations, 2019). Circularity can be characterized by three key factors:

1. Increasing the utilization of assets and products.

Ex: Distributing the unconsumed food to economically disadvantaged members of a community instead of disposing of them as waste – social circularity

2. Increasing their lifetime.

Ex: Utilizing the household consumed water for irrigation – environmental circularity

3. Creating a new life.

Ex: Recycling plastic waste for road construction – environmental and economic circularity

In addition to the Sustainable Development Goals and climate goals, the transition to circular cities would aid cities to achieve many of the persistent urban challenges like improved urban green spaces, mobility, biodiversity, and economic development. The following are a few examples of how Asian cities have adopted innovative and sustainable strategies that support the city in social, environmental, and economic ways by either increasing the utilization or increasing the lifetime or creating a new life for the assets and products.

Since the dawn of civilization, solid waste has been produced. Due to the low population density at the time, solid waste was disposed of in large open areas called landfills. However, one of the enduring issues of global urbanization has been how to manage our own waste without harming the environment or citizens' health. Greater economic prosperity and an increasingly urban population usually result in increased solid waste production, a common phenomenon in developing countries. However, improper waste disposal has significant social, environmental, and economic implications, including the spread of infectious diseases, deterioration of air quality, and increased treatment costs and treatment plants for pollutants (Chattopadhyay et al., 2009). Solid waste collection, segregation, transportation, and disposal are often unscientific and chaotic in India which led to unregulated and uncontrolled disposal of solid waste on the outskirts of cities. Such overflowing landfills have negative environmental consequences like soil, groundwater, and air pollution, as well as contribute to global warming.

Kolkata is one of India’s fastest-growing cities, with a high urban density in terms of population and built-up area. It has a population of over 8 million and generates municipal solid waste of about 3,000 tonnes per day (Chattopadhyay et al., 2009). Waste mounds at the Kolkata dumping sites used to reach as high as 16 meters, leading to land, water, and air pollution. In addition, the dumping of solid waste in the River Ganges has resulted in the extinction or endangerment of biodiversity in the region (C40 Cities, 2017). The lack of waste segregation at the source, a low percentage of the house to house collection, low operational efficiency of the waste transportation system, low collection efficiency, and inadequate recycling system are identified as the major problems of solid waste management in Kolkata (Chattopadhyay et al., 2009).

The city has begun to segregate its waste under the ‘Kolkata Solid Waste Management Project’ in an attempt to address the problem of waste management, with the aim of creating a cleaner, healthier, and sustainable city. Recycling, composting organic waste, burying inert waste, and treating septic sludge were all part of the initiative. The project not only focused on improving the infrastructure but also on improving citizen involvement through elaborate public awareness campaigns. As part of the project, a common Regional Waste Management center was built, which includes a sanitary landfill, leachate treatment plant, and septic tank sludge treatment plant, as well as five composting centers. Additionally, the project will monitor air quality, minimize landfill methane concentrations and prevent groundwater contamination within 50 meters of the Regional Waste Management Centre’s perimeter (C40 Cities, 2017).

Ultimately, the ambitious initiative seeks to eliminate open dumping and waste burning entirely, as well as achieve 100% waste segregation at the source. Since the program began, segregation rates have increased by up to 80%, and open dumping has decreased by up to 35% (C40 Cities, 2017).

In urban areas, buildings and transportation account for a significant portion of energy demand. Because of the emission of greenhouse gases and other pollutants, energy consumption, which is mostly derived from fossil fuels, has an impact on climate and air quality. The IPCC has recognized compact urban form as a key climate mitigation measure, owing to lower per capita energy usage. High-density cities can accommodate more people in a smaller space. As a result, there is a movement toward taller buildings in order to accommodate the growing population.

However, researchers at UCL’s Energy Institute reported in 2017 that high-rise office buildings with 20 or more storeys use approximately two and a half times more energy per square meter of floor area than low-rise buildings with 6 storeys or less.

Tokyo, Japan’s capital, is one of the world’s largest metropolitan cities, with a day population of about 15.6 million as of 2010. The region, which generates nearly 20% of the country’s GDP, is by far the most important economic center in the country. Tokyo’s annual energy consumption was around 832 Peta Joules in 2013, with the industrial and commercial sectors accounting for more than 68% of the total (Doll & de Oliveria, 2017). As the country’s largest economic hub, Tokyo faces urban development issues due to a steady influx of people. Tokyo, with its high-rise buildings, has an issue to address in order to achieve maximum energy efficiency and reduce total energy usage to improve the city’s sustainability and climate resilience.

By enacting a mandatory cap-and-trade and emission reporting scheme, the Tokyo Metropolitan Government (TMG) has devised a novel solution to address the problem of unsustainable energy use in the city. All large-scale buildings are required to limit carbon dioxide emissions under this innovative program, which is supplemented by an emission trading system (ETS) for those facilities that are unable to reduce the emissions internally. Capped facilities must minimize carbon dioxide emissions over each compliance cycle and submit annual emission reduction plans. Large tenants of the buildings are also required to submit emission reduction plans and collaborate with owners for efficient energy use. Under the Mandatory ‘Tenant Rating and Disclosure Program’ each apartment unit is given an evaluation and a rating, which is published on the city’s website. Although Tokyo already works with property owners to reduce energy consumption, tenant participation is critical to accelerating efficient energy use (C40 Cities, 2017).

By making tenants responsible parties, the program not only raises awareness and accountability but also incentivizes owners and tenants to cooperate for energy conservation. The mandatory submission of reports has aided facilities and tenants in visualizing energy usage trends and identify areas for improvement. According to a 2013 survey, 56% of tenants made energy-saving recommendations to the building owners, suggesting that tenants are willing to collaborate with the building owners (Doll & de Oliveria, 2017). Furthermore, the city facilitates the disclosure program by offering key information about how to maximize energy efficiency. Even the medium and small tenant buildings are involved in the program through a Carbon Certification Program that rewards high-performing buildings and making the energy efficiency data open for the public.

Tokyo plans to cut building energy usage in all tenant buildings by around one-sixth by 2020, and to cut city-wide energy use by 30% by 2030, thanks to the innovative initiatives of ‘Cap- and-Trade and Emission Reporting Scheme’, ‘Tenant Rating and Disclosure Program’ and ‘Carbon Certification Program’.

Asia has experienced a booming economy, massive rural to urban migration, and rapidly growing urban cities with shrinking green spaces over the past decade. Among the many advantages of urban green spaces, such as reducing temperature and noise, improved air quality, they also provide an environment that benefits our physical, mental and social well-being. With such a large influx of people moving into cities, urban green spaces are being encroached and destroyed in most Asian cities, posing a serious threat to ecological balance and healthy living.

The demand for cooling in hot and humid Hong Kong is increasing in tandem with global temperatures, resulting in increased energy usage of air conditioners and cooling systems, which contributes to global warming. Hong Kong is already a densely packed concrete jungle with minimal green spaces and artificial cooling systems taking a huge toll on the city’s sustainability. Hong Kong is expanding its city’s spatial reach to meet the city’s growing population and is currently constructing its second central business district on the old Kai Tak airport named Kowloon East. In order to create a unique and sustainable community, the city must be built economically appealing while still maintaining the region’s climate resilience and carbon dioxide mitigation capabilities.

To ensure the climate change impacts were mitigated, the city incorporated green development policies and instruments into the neighborhood’s redevelopment plan. The redevelopment plan not only aims to transform Kowloon East into Hong Kong’s second central business district but also a resilient, low-carbon community. Its future-proofing plan includes a district cooling system that pumps the coolant from two central chillers to approximately 1.73 million square meters of floor space through more than 39 kilometers of leak-detection piping. The system, which uses seawater from the surrounding Kowloon Bay, is projected to save 85 million kWh of electricity annually once completed in a city where cooling systems account for 30% of electricity demand (C40 Cities, 2017).

The system’s advantages for building owners and tenants go far beyond carbon dioxide emission reductions, such as developers saving money on cooling equipment. Residents will also enjoy a more spacious and liveable region without the pollution, noise, and space taken up by traditional cooling systems. In addition, new and existing buildings in the region will be required to obtain green certifications. As of 2017, Kowloon East’s 30 green building projects have lowered carbon dioxide emissions by 56,100 metric tonnes per year. Also apart from the energy savings, the redevelopment plans encourage active mobility within the region by enhancing walkability and creating well-connected pedestrian networks. One-third of Kowloon East will be public space, with 60% of that land constituting green spaces, promoting a safe, healthy, and close to nature environment (C40 Cities, 2017).

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Sai Ganesh Veeravalli