Densification: Drivers, Dividends and Debates

By 2050, there will be another 2.5 billion people living in the world’s cities. Governments have three main options to cope with this huge influx of people – to allow cities to expand and sprawl; to build new towns and cities; or to embrace the densification of cities within their existing boundaries.

Densification is therefore a crucial part of the urban future. This strategy allows cities to accommodate more people within their existing footprint, promoting better connectivity, improved amenities, stronger social interaction and increased productivity.

The move towards densification has three key drivers – population growth, re-urbanisation and environmental and sustainability concerns. However, a number of less obvious trends are also encouraging higher density development, including digitisation, linkages to infrastructure investment, increasing volumes of capital flowing into cities, and new preferences in architecture and design.

Some cities have already embraced densification. Singapore, Vienna, Toronto, Paris and Barcelona can be seen as positive examples of high density. Toronto for instance has concentrated its development in its Downtown and Central Waterfront districts, with huge numbers of high-rise buildings in these central areas, while allowing established residential areas to remain unchanged. Many Asian cities have also embraced ‘vertical density’. For example, Seoul, experiencing rapid population growth in the 1980s, focused on the development of high density suburban districts based around new stations on the city’s extensive metro network. In Europe, the high density, but fairly low rise, structure of Barcelona’s neighbourhoods has been inspired by both topographical restrictions to sprawling expansion and a concerted effort to develop brownfield sites, especially around the time of the Barcelona Olympics.

Yet many cities remain wary of densification, fearing overcrowding, anonymity and a loss of privacy. Local governments must deal with the concerns of current residents which can take precedence over the long-term needs of the city when it comes to urban planning. The experiences of failed densification attempts remain in the memories of many, who associate high density with poorly constructed residential tower blocks, isolated business districts, and soulless suburban shopping centres.  A large part of the challenge lies, therefore, in debunking well-established myths and staunchly-held opinions about densification. In recent years, people have begun to display a preference for dense urban living – but there is still some way to go.


Part of the issue is that density can be difficult to grasp fully. For one thing, it can be challenging to define and calculate. Our understanding of a city’s density depends on what is being measured, whether that is residents, employees or buildings, or whether it be an individual district, the city itself or the whole metropolitan region. Overall, understanding of density remains vague, often linked to wide-ranging debates on urbanisation, sprawl, polycentricity, the ‘shrinking city’ and high-rise buildings, to name but a few.

Nevertheless, we can distinguish between ‘good’ and ‘bad’ forms of density – though the line can be blurred depending on who the development is geared towards. ‘Good’ density can be generally understood as: mixed-use; connected; planned; cohesive; liveable; spacious; well-designed; and green. ‘Bad’ density, on the other hand, often has a single use, is lacking in amenities and is over-dependent on one mode of transport.

Densification, if done right, can bring many economic, social and environmental advantages. It can be more economically efficient (through mixed usage), encourage infrastructure investment, improve productivity and promote innovation. While the relationship between society and density is more complex and can be paradoxical, high density development can enhance access to education, healthcare and culture, while promoting walkability and cycling. By providing an alternative to greenfield development, and also promoting public transport and opportunities for shared energy technologies, densification can be a more environmentally friendly approach to development.

If done wrong, however, it can lead to higher costs, price increases, over-crowding, income-based exclusion, loss of open space and congestion. Therefore, the importance of good design and continued debate is vital.

Cities are facing a choice over their future development. Rather than building new cities or allowing cities to sprawl, well-planned densification offers the solution cities need to manage increasing populations in a sustainable way. Norms and ingrained behaviours are slowly changing, but many barriers remain – not least negative perceptions of high-density developments. Density makes economic, social and environmental sense, and will provide a competitive advantage in the future. However, a broad mix of interest groups is needed to push the debate forward and a clear agenda for advocacy, demonstration and public education is required.

Read more in the ULI report, Density: Drivers, Dividends and Debates

About the Author

Greg Clark has spent more than two decades putting his passion for cities to good use, by advising and mentoring global cities, firms and institutions. He has worked with over 100 cities around the world and holds senior advisory roles at international bodies including the OECD, Brookings Institution, ULI, and the Future Cities Catapult. A prolific author, Greg has published ten books to date on cities and investment practices, with three more in the pipeline for 2016-17. And as Chairman of The Business of Cities research and intelligence group, Greg leads a small high calibre team that advises and reports on global trends and changes in cities. In his academic life Greg is Hon Prof of City Leadership at UCL and co-chairman of the UCL City Leadership initiative, Visiting Professor at Strathclyde University, and Global Fellow at LSE Cities. He has received international awards for his work from cities as far afield as Barcelona, Brisbane, London, and Toronto and in 2016, Greg was honoured by HM Queen Elizabeth II with a CBE for his services to city and regional economic development. Meanwhile, outside of the day jobs, Greg is an avid tennis player, wine enthusiast, and lifelong follower of Arsenal FC.

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