Green infrastructure can cool our cities. So what are planners waiting for?

A living wall in action: Patrick Blanc's "Trussardi Cafe: Unexpected Garden" on display in Milan in 2008. Image: Getty.

Our cities are getting hotter, more crowded and noisier. Climate change is bringing more heatwaves, placing pressure on human health, urban amenity, productivity and infrastructure.

Urban residents naturally want to stay cool. Air conditioning is the usual choice, but it can be expensive to run. Air conditioning also adds carbon pollution, creates noise and can make outdoor spaces hotter.

So what else can we do to manage increasing urban heat? And who has the ability to act?

Urban planners are increasingly involved in developing and delivering urban greening strategies. While it seems like a “no brainer” to green cities, our international research shows that planners are not always comfortable with this idea.

However, green infrastructure – including street trees, green roofs, vegetated surfaces and green walls – is emerging as a viable way to help cities adapt to increased heat. Uptake of these technologies is slowly increasing in many cities around the world.

Green walls cooling a building in Singapore. Image: Tony Matthews.

The Australian government has recognised this trend. An agenda to green Australia’s cities is now in place. Stated aims include managing climate change impacts, reducing urban heat, improving urban well-being and increasing environmental performance.

This urban greening agenda is part of the Clean Air &Urban Landscapes hub, under the National Environmental Science Program.

Benefits of urban greening

The broadening appeal of green infrastructure is helped by the fact it offers multiple benefits.

For example, shading from strategically placed street trees can lower surrounding temperatures by up to 6℃, or up to 20℃ over roads. Green roofs and walls can naturally cool buildings, substantially lowering demand for air conditioning. Green infrastructure can also provide habitat for wildlife, recreational opportunities for people, better management of stormwater runoff and improved urban aesthetics.

Street trees and green walls helping to reduce urban temperatures. Image: Tony Matthews.

Hard surfacing, including concrete, asphalt and stone, is common in cities. It can increase urban temperatures by absorbing heat and radiating it back into the air. Green infrastructure can minimise this difficulty, as it better regulates ambient air temperatures. Foliage allows local cooling through evapotranspiration, where plants release water vapour into the surrounding atmosphere.

Why planners are cautious

Our research examined urban planners' attitudes towards green infrastructure use in Australia, England and Ireland. We found that planners are broadly aware of green infrastructure as an urban intervention. They understand its use, application and capacity to provide multiple benefits, especially in terms of managing urban heat.

The planners we interviewed, while recognising the potential value of green infrastructure, strongly cautioned that delivering the technology can be an uncertain process. The biggest barrier cited was that planning departments are not experienced with green infrastructure.

Put simply, they tend to avoid it because it has not traditionally featured on planning agendas. Like any new planning endeavour, green infrastructure can create institutional, legal, economic, social and environmental challenges.


Some of the biophysical challenges associated with green infrastructure delivery are novel. Choosing appropriate forms of vegetation, for example, may be difficult. Decisions must be made based on prevailing climactic conditions, drainage capacity and species growth patterns.

Will root systems damage buildings or underground utility networks? Might trees topple during storms and damage houses? Are roofs strong enough to support a rooftop garden? Planners may not be able to answer these questions, which creates a need for external experts to advise them.

Our findings also highlight socio-political factors as barriers. These include governance concerns such as the political context in which planning decisions are made.

Management issues also feature. Chief among these are government commitments to budget for green infrastructure delivery and management.

Planners are also wary of public involvement. They know that public sentiment about green infrastructure can be influenced by perceptions of modified access, changed use, or loss.

What can be done?

The urgency for providing urban green infrastructure increases as climate change makes our cities hotter. Our research suggests the principal task for planners is to overcome embedded practices and to accept green infrastructure as an emerging but permanent urban feature.

This will not be easy. For example, a decision to use a road easement for green infrastructure may require multiple meetings with other government departments, utility companies and residents. Planners will need to coordinate these, manage stakeholder expectations and ensure cost sharing where necessary.Legal, economic, social and environmental issues will require innovative solutions.

Planners will increasingly be tasked to deliver green infrastructure in cities. They will need to be clear on its value, be prepared to lead its delivery and learn from new challenges and solutions encountered along the way.

But urban residents all over the world stand to benefit if planners can successfully meet this challenge – particularly as hotter temperatures threaten urban comfort and habitability.The Conversation

Tony Matthews is a lecturer in urban & environmental planning, and Jason Byrne an associate professor in environmental planning, at Griffith University, Queensland.

This article was originally published on The Conversation. Read the original article.

 
 
 
 

The Adam Smith Institute thinks size doesn’t matter when housing young professionals. It’s wrong

A microhome, of sorts. Image: Wikimedia Commons.

The Adam Smith Institute has just published ‘Size Doesn’t Matter’, a report by Vera Kichanova, which argues that eliminating minimum space requirements for flats would help to solve the London housing crisis. The creation of so-called ‘micro-housing’ would allow those young professionals who value location over size to live inside the most economically-active areas of London, the report argues argues.

But the report’s premises are often mistaken – and its solutions sketchy and questionable.

To its credit, it does currently diagnose the roots of the housing crisis: London’s growing population isn’t matched by a growing housing stock. Kichanova is self-evidently right in stating that “those who manage to find accomodation [sic] in the UK capital have to compromise significantly on their living standards”, and that planning restrictions and the misnamed Green Belt are contributing to this growing crisis.

But the problems start on page 6, when Kichanova states that “the land in central, more densely populated areas, is also used in a highly inefficient way”, justifying this reasoning through an assertion that half of Londoners live in buildings up to two floors high. In doing so, she incorrectly equates high-rise with density: Kichanova, formerly a Libertarian Party councillor in Moscow, an extraordinarily spread-out city with more than its fair share of tall buildings, should know better.

Worse, the original source for this assertion refers to London as a whole: that means it includes the low-rise areas of outer London, rather than just the very centrally located Central Activities Zone (CAZ) – the City, West End, South Bank and so forth – with which the ASI report is concerned. A leisurely bike ride from Knightsbridge to Aldgate would reveal that single or two-storey buildings are almost completely absent from those parts of London that make up the CAZ.

Kichanova also argues that a young professional would find it difficult to rent a flat in the CAZ. This is correct, as the CAZ covers extremely upmarket areas like Mayfair, Westminster, and Kensington Gardens (!), as well as slightly more affordable parts of north London, such as King’s Cross.

Yet the report leaps from that quite uncontroversial assertion to stating that living outside the CAZ means a commute of an hour or more per day. This is a strawman: it’s perfectly possible to keep your commuting time down, even living far outside of the CAZ. I live in Archway and cycle to Bloomsbury in about twenty minutes; if you lived within walking distance of Seven Sisters and worked in Victoria, you would spend much less than an hour a day on the Tube.

Kichanova supports her case by apparently misstating research by some Swiss economists, according to whom a person with an hour commute to work has to earn 40 per cent more money to be as satisfied as someone who walks. An hour commute to work means two hours travelling per day – by any measure a different ballpark, which as a London commuter would mean living virtually out in the Home Counties.

Having misidentified the issue, the ASI’s solution is to allow the construction of so-called micro-homes, which in the UK refers to homes with less than the nationally-mandated minimum 37m2 of floor space. Anticipating criticism, the report disparages “emotionally charged epithets like ‘rabbit holes’ and ‘shoeboxes,” in the very same paragraph which describes commuting as “spending two hours a day in a packed train with barely enough air to breath”.


The report suggests browsing Dezeen’s examples of designer micro-flats in order to rid oneself of the preconception that tiny flats need mean horrible rabbit hutches. It uses weasel words – “it largely depends on design whether a flat looks like a decent place to live in” – to escape the obvious criticism that, nice-looking or not, tiny flats are few people’s ideal of decent living. An essay in the New York Times by a dweller of a micro-flat describes the tyranny of the humble laundry basket, which looms much larger than life because of its relative enormity in the author’s tiny flat; the smell of onion which lingers for weeks after cooking a single dish.

Labour London Assembly member Tom Copley has described being “appalled” after viewing a much-publicised scheme by development company U+I. In Hong Kong, already accustomed to some of the smallest micro-flats in the world, living spaces are shrinking further, leading Alice Wu to plead in an opinion column last year for the Hong Kong government to “regulate flat sizes for the sake of our mental health”.

Amusingly, the Dezeen page the ASI report urges a look at includes several examples directly contradicting its own argument. One micro-flat is 35 m2, barely under minimum space standards as they stand; another is named the Shoe Box, a title described by Dezeen as “apt”. So much for eliminating emotionally-charged epithets.

The ASI report readily admits that micro-housing is suitable only for a narrow segment of Londoners; it states that micro-housing will not become a mass phenomenon. But quite how the knock-on effects of a change in planning rules allowing for smaller flats will be managed, the report never makes clear. It is perfectly foreseeable that, rather than a niche phenomenon confined to Zone 1, these glorified student halls would become common for early-career professionals, as they have in Hong Kong, even well outside the CAZ.

There will always be a market for cheap flats, and many underpaid professionals would leap at the chance to save money on their rent, even if that doesn’t actually mean living more centrally. The reasoning implicit to the report is that young professionals would be willing to pay similar rents to normal-sized flats in Zones 2-4 in order to live in a smaller flat in Zone 1.

But the danger is that developers’ response is simply to build smaller flats outside Zone 1, with rent levels which are lower per flat but higher per square metre than under existing rules. As any private renter in London knows, it’s hardly uncommon for landlords to bend the rules in order to squeeze as much profit as possible out of their renters.

The ASI should be commended for correctly diagnosing the issues facing young professionals in London, even if the solution of living in a room not much bigger than a bed is no solution. A race to the bottom is not a desirable outcome. But to its credit, I did learn something from the report: I never knew the S in ASI stood for “Slum”.