Is increasing population density the solution to the land-squeeze in successful cities?

Manchester. Could get some more people in there. Image: Getty.

The Centre for Cities' recent City Space Race report highlights a dilemma that most growing cities are currently facing: they need to build more houses and offices, but regulations and local political pressures restrict them from expanding, particularly when it comes to green belt development.

In theory, there is a simple way for cities to have their cake and eat it too. Increasing density — allowing taller buildings on the same space — should enable cities to provide more property space without having to expand outwards.

This idea is often the source of heated debate in public discussions about tackling the housing crisis in our most economically vibrant cities. But is increasing density the right solution for cities with high demand for land – and how viable is it in practice?

High average, low extremes

The UK is already a dense country. It has one of the highest average built-up densities — the population density of inhabited areas — across European countries.

But average national density is a blunt measurement of population versus land in a country and offers little insight into the variations across and within cities. When we look closer at UK cities, it’s clear that few urban neighbourhoods have the level of density found in other European cities. The densest square kilometre in the country, with a population of 20,000, is in the London neighbourhood of Maida Vale — an affluent area which doesn’t exactly fit the stereotype of an urban jungle.

In contrast, some urban areas on the continent exceed 50,000 inhabitants — for instance, the most populated square kilometre in Europe is in Barcelona with 53,000 inhabitants.

The chart below plots all square kilometre units that are populated with more than 10,000 inhabitants for a selection of countries. In the UK, 86 per cent of these areas have between 10,000 and 15,000 inhabitants, and the other 18 per cent have less than 20,000. By comparison, all other main European countries have areas exceeding 20,000 inhabitants, with Italy, France and Spain having a considerable share of very high-density neighbourhoods.

Source: Eurostat.

The benefits of population density

This means there is scope to increase density in UK cities, and in particular in residential neighbourhoods. This would have many benefits: not only would it allow cities to accommodate new residents without expanding, it would also improve cities’ transport accessibility and planning.

Let’s focus on this last point. Transport systems in denser cities are likely to be more efficient because they can reach a larger share of the population at lower costs. Consider Hong Kong, an extreme case of dense population settlement. Only 7 per cent of the working population commutes using their private car according to the Hong Kong statistics department.

In contrast, 33 per cent of Londoners travel to work by car (still a reasonable figure against international standards), while this group is bigger still in Liverpool (57 per cent of commuters), Manchester and Birmingham (64 per cent), as shown on our data tool.

High density in Hong Kong makes the transport network more efficient too: the metro network is short in length (210 km), and yet it serves 1.1m workers every day. In comparison, “only” 800,000 commuters use the London Underground, according to the 2011 census, despite the network being twice as long (402 km).

In other words, denser cities lead to better transport accessibility, and this, in turn, means better access to jobs, less traffic congestion and fewer carbon emissions. (As research by LSE cities shows, there is a clear negative correlation between urban population density and carbon emission per capita.)

The challenges of increasing density

As such, increasing population density clearly brings significant advantages. However, it is not easy to achieve, and there are two main reasons for this.

First, some local residents are concerned that densification will alter and threaten the nature and shape of their city, and this puts political pressure on councils not to act. That’s because densification is often amalgamated with high-rise buildings.

 But London does not have to become Hong Kong. If only 5 per cent of the capital’s built up area had the density of Maida Vale, it could host an additional 1.2m people, without the need to expand outwards.

Second, it is easy to forget the administrative and technical complexities of densification. In concrete terms — both literally and figuratively — densification means knocking down existing buildings to build new ones. This is time-consuming and it has a cost. Moreover, unless a city has in place an overarching plan to increase densification across its length and breadth, it will take decades for it to become more compact.


What should be done?

For growing cities to build more houses and commercial space, there are only two options: build up or build out.

Building up (densification) has many great benefits, but it is also difficult to deliver. To have a chance to happen, densification must be at the core of strategic planning policies and cities must have the necessary power, determination and leadership to bring it about. However, this is a long-term strategy, with benefits that will only be reaped in the long-term.

In the meantime, a number of cities have an urgent need to build more houses, and lack of action puts pressure on the existing stock, as highlighted in our report. Only building out (expanding) will enable them to respond to this need quickly enough. In most cases, this means that some green belt land must be released for development.

This is a difficult trade-off, but there is a middle ground between full densification and full expansion. For instance, cities could release plots of green belt land that are found within walking distance to an existing train station, and ensure that new developments have higher densities (in a Maida Vale rather than a Hong Kong style). This would allow cities to create a large number of homes on a small fraction of the land, limiting encroachment on the green belt and allowing easy transport access to the city.

Hugo Bessis is a researcher for the Centre for Cities, on whose blog this article originally appeared.

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In many ways, smart cities are really very dumb

Rio de Janeiro’s control centre. Image: Getty.

It’s not news that anything and everything is increasingly being prefaced with “smart”: phones, watches, homes, fridges, and even water (yes, smartwater exists). And it’s not unintentional either. 

Marketeers know that we, the public, are often stupid enough to believe that thanks to their technology, life is better now than it was way back in, say, the primitive Nineties. Imagine having to, like a Neanderthal, remember how to spell words without an autocorrecting algorithm, or open the fridge door to check if you’d run out of milk, or, worse still, interact with actual people.

So it’s hardly surprising that we’re now also witnessing the rise of the so-called “smart cities”; a concept which presupposes that cities that are not technologically  “smart” are dumb, which, as anyone interested in the millennia-old history of cities — from the crypto-currency grain storage algorythms of ancient Mesopotamia to the complex waste infrastructure of ancient Rome, to London’s public transport infrastructure — will know, is not true.

Deployed in these smart cities are cameras and other networked information-gathering devices, load cells and other “sensing devices” detecting passing pedestrians and vehicles, audio surveillance devices listening for gunshots – and even vending machines equipped with biometric sensors to recognise your face. This is not to mention beacon technology — tiny anonymous looking black boxes hidden in trees and on lampposts — which transmits advertising, offers and other information directly to smart phones in the vicinity. 

If that doesn’t seem sinister enough, take, for example, Rio de Janeiro, where, in 2014, the International Business Machines Corporation designed a mammoth “control centre” that integrates data from 30 agencies for the city’s police. 

Described by the Guardian as having “the functionality of a Bond villian’s techno lair”, the then local mayor, Eduardo Paes, claimed the centre was making the city safer while using technology to deploy its “special” police unit to carry out the state’s “pacification programme”. Launched in 2008, the programme, which aims to push out drug gangs from Rio’s favelas, has been criticised by Amnesty International: “in January and February 2017 in Rio de Janeiro alone, at least 182 people were killed during police operations in marginalized neighbourhoods (favelas) – a 78 per cent increase in comparison to the same period in 2016”.

Sinister or not, as smart cities grow, they create new problems. For example, as urbanist Adam Greenfield writes in Radical Technologies: The Design of Everyday Life, neither the algorithms nor their designers are subject to the ordinary processes of democratic accountability – a problem that international academics are currently attempting to tackle.  


“We need to understand that the authorship of an algorithm intended to guide the distribution of civic resources is itself an inherently political act,” writes Greenfield. “The architects of the smart city have utterly failed to reckon with the reality of power.”

The Real Smart Cities project, founded by Dr Gerald Moore, Dr Noel Fitzpatrick and Professor Bernard Stiegler, is investigating the ways in which so-called “smart city” technologies present a threat to democracy and citizenship, and how digital tools might be used create new forms of community participation.

Fitzpatrick is critical of current discourses around smart cities, which he says “tend to be technical fixes, where technology is presented as a means to solve the problems of the city.” The philosophy underpinning the project is “that technologies function as forms of pharmacology”, he adds, meaning that they can be both positive and negative. “The addictive negative effects are being felt at an individual and collective level.” 

An example of this lies in the way that many of these smart cities replace human workers with disembodied voices — “Alexa we need more toilet roll” — like those used to control the Amazon Echo listening device — the high priestess of smart home. These disembodied voices travel at the speed of light to cavernous, so-called “fulfilment centres”, where an invisible workforce are called into action by our buy-it-now, one-click impulse commands; moving robotically down seemingly endless aisles of algorithmically organised products arranged according to purchase preferences the like of which we never knew we had — someone who buys a crime novel might be more likely to go on and buy cat food, a wireless router, a teapot and a screwdriver. 

Oh to be the archeologists of the future who while digging through mounds of silicon dust happen upon these vast repositories of disembodies voices. That the digital is inherently material and the binary of virtual/real does not hold — there is no cyberspace, just space. Space that is being increasingly populated by technologies that want to watch you, listen to you, get to know you and sense your presence.

One project looking to solve some of the problems of smart cities is that of the development of a “clinic of contribution” within Pleine Commune in greater Paris (an area where one in three live in poverty).This attempts to deal with issues of communication between parents and children where the widespread use of smartphones as parental devices from infancy is having effects on the attention of young children and on the communicative abilities between parents and children. 

This in turn forms part of a wider project in the area that Stiegler describes as “installing a true urban intelligence”, which moves beyond what he sees as the bankrupt idea of smart cities. The aim is to create a “contributory income” in the area that responds to the loss of salaried jobs due to automation and the growth and spread of digitisation. 

The idea being that an income could be paid to residents, on the condition that they perform a service to society. This, if you are unemployed, living in poverty and urban deprivation, sounds like quite a simple and smart idea to try and solve some of the dumb effcts of the digital technology that's implemented in cities under the ideology of being “smart”.