Yemeni architecture uses local high insulation materials and dense building clusters to create liveable environments in a harsh arid climate. Image courtesy of Hidden Architecture

Why compact cities achieve smarter growth

About the Author
Rony Hobeika
Rony Hobeika is a senior masterplanner at Atkins Middle East. He holds a bachelor’s in architecture, a master’s in urban planning and policy, and an MBA. He’s also specialised in green building and has multiple certifications in sustainable urban design. Rony publishes regularly on topics such as sustainable regions, net-zero smart cities, post-pandemic planning, energy-efficient buildings, and the digital transformations in the built environment.
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Compact cities not only preserve the environment, but they also generate synergies across urban systems that are smarter and provide more equitable growth.

The past few decades have witnessed a remarkable surge of interest in the footprint of cities. Since growth often happens on the urban periphery, it not only threatens ecological devastation, but it has also been linked to problems, such as unhealthy lifestyles, congestion, pollution, and crumbling infrastructures. The concern becomes more alarming with the prediction that 70 percent of the earth’s population is expected to live in cities by 2050. So, the question arises: can cities grow in a smarter, more efficient way?

In search for the golden rule of sustainable urban development, one theme has prevailed: the compact city can be defined as the “increasing built areas and population densities and intensifying economic and social activities in pursuit of sustainability benefits from the concentration of activities.” Following the idea that compressing urban development can in fact lead to smarter growth, the following points outline how one planning policy can deliver mutually reinforcing contributions to sustainability and smart goals.

Preservation of Farmland
Farmland is an essential resource for the security of food systems, industries, livelihoods, and climate resilience. However, it has been increasingly threatened by urbanisation, with estimates that over 43 percent of global prime land has already been irrevocably lost. Scarcities in local productive soils required to feed fast growing populations forces the expansion of supply chains, increasing food prices and risk. Since fertile soil most often lies in proximity to major cities, compact development is a smart step towards resilience.  

The Metropolitan Green Belt of London protects sensitive habitats, but also provides respite to the residents of the city, Image courtesy of CPRE

Ecological Conservation
Biodiversity can also be protected by compacting growth. Blue and green ecosystems like forests, dunes, rivers, and wetlands are home to rich habitats that are essential for regenerative life, and their destruction creates environmental imbalances with dire effects. Moreover, numerous studies have shown that the integration of nature in compact-oriented planning can have multiplicative positive impacts on the resilience and wellbeing of people living in cities, generating over $3 trillion in business opportunities and millions of jobs by 2030.

Low-Impact Mobility
Populations in compact cities use less energy for transport because they live closer to their jobs and daily amenities, thus commuting shorter distances. Also, denser cities render public transit such as light rail and buses, as well as shared micro-mobility options, which are more viable due to higher user demand per station and shorter travel lengths. This explains why a UN-HABITAT study showed that a density increase of 1,000 units per square mile can lead to a 1,200-mile reduction in private vehicle use per household per year.

The Ørestad is a dense transit-oriented development built to synergize with new metro and railway lines in Copenhagen. Image courtesy of The Global Grid

Efficient Infrastructure and Welfare
Compactness creates multiple efficiencies in utility provision. First, capital and operational costs of public services and facilities, such as energy and waste, drop in proportion to population served due to efficiencies of scale economies. For example, power efficiency is improved due to less network installations, maintenance costs, and transmission losses. Second, physical proximity enables better integrated systems and improved circular economies. For instance, material recycling processes become more practical and affordable due to savings in handling and transportation of waste generated by denser residential neighbourhoods.  

Higher Building Environmental Performance
Numerous studies show that the compact fabric of historic cities in moderate and extreme climates reduces building energy demand for cooling and heating compared to sprawled forms. This is because larger floor coverage and adjacent structures minimise building facades’ exposure to environmental factors, such as solar gains and heavy winds, thereby lessening the need for climatisation. Another advantage is that compact buildings form shaded streets and public spaces improving walkability and outdoor recreation.

Lower Carbon Emissions
The combination of energy-efficient transport models, circular utilities, and green buildings can significantly reduce the amount of greenhouse gases released, since these sectors alone are responsible for more than two-thirds of emissions. Moreover, when coupled with landscape planning (creating carbon sinks), the result is a step towards net-zero carbon. This has been corroborated in countless studies. One research by Climate Action found that there is a general correlation between higher urban density and lower emission levels.

Economic Robustness and Better Livelihoods
The productivity of cities and livelihoods depends on accessibility, which is why businesses and people bid high rents to be in central locations. Urban sprawl, on the other hand, cost the US $87 billion in lost productivity in 2018. Thus, a compact urban form with an effective mobility strategy reduces travel times and delivers benefits of broader job access, lower costs of doing business, labour supply and demand flexibility, as well as opportunities for specialised clustering.

High Innovation Potential
Human ingenuity is positively linked to agglomeration. The reason is because innovation happens through casual communication, tinkering, and experimentation that people engage in when they participate in activities in the workplace and common spaces. Under the right conditions, a more compact urban living may enable people to interact better, breeding more creative and innovative ideas conducive for growth. 

Enhanced Property Values
In addition to more sellable construction, property values can be boosted by sustainable neighbourhood design. Dense areas that combine a demographic mix with a rich variety of commercial and cultural amenities can create a strong sense of community and belonging. Indeed, pre-Covid, a back-to-the-city movement was in full swing in the US, as people sought such vibrant and cosmopolitan lifestyles in revitalised urban quarters.

Paris’s central quarters feature some of the densest and most valuable properties due to sound neighbourhood design principles. Image courtesy of Lodgis Blog

Disputes have long emerged over compact cities. For instance, many studies have shown that artificially containing urban land expansion, particularly when coupled with restrictive zoning, can magnify property prices to unaffordable levels, pushing out the city’s productive classes. Other criticisms concern inevitable overcrowding. This creates congestions that cripple the movement of people, as well as potential hygiene and pollution problems as excrement, noise, and air fumes become more concentrated. Finally, green areas may be curtailed because idle lands will need to compete with income-generating assets with repercussions on the city’s heat island effect.

The debate takes a more nuanced turn, especially as it relates to policy. For example, conflicts have arisen over issues, such as the scale of densification and what metrics to monitor it, whether market-led or regulatory policies are more effective, and what processes should be followed to evaluate requests to unlock peripheral lands for development. These concerns and many others exhort urban planners to carefully approach densification policies, and to do so by means of engaging stakeholders, countering externalities, and sensibly considering trade-offs between competing priorities and targets.

Overwhelming as they sometimes are, disadvantages of compact forms should not be dissuasive. In fact, they are but symptoms of urban mismanagement that can be mitigated through sound governance and design. On the contrary, the compact city’s enduring legacy proves that it still has merit, and that its benefits are still pertinent in achieving our aim to live in smarter and more sustainable cities.