urban sprawl, gold coast

“High-density living worse for environment than suburban sprawl, new study shows”.

The headline, courtesy of Domain this week, was even more shocking as it came out of research released at the gargantuan international Council on Tall Buildings and Urban Habitat conference in Sydney this week, which one would have expected to be putting a positive spin on high-density living.

“The findings are a little surprising to us all,” CTBUH executive director Dr Anthony Wood told the paper.

So what did the research find?

High-rise residents were using 27 per cent more electricity and gas per person than those in detached houses (and 4.6 per cent more on a square metre basis). Also, embodied energy was a massive 72 per cent higher on a per person basis (and 49 per cent more intensive per sq m).

The “bombshells” continued.

Those living in inner city areas spent 11 per cent more time travelling, and owned more cars per person (0.6) than those in the suburbs (0.5).

Scandalous! Well not so much if you look a little closer.

That the energy requirements of tall buildings can be greater than low-density housing is no real surprise.

Lynne Blundell, all the way back in 2011, did a piece on tall building sustainability that ended up as one of our most read articles of all time.

It too found some pretty unfavourable results in terms of tall building impact around both embodied and operational energy.

But it’s not the total story. As CRC for Low Carbon Living’s Professor Deo Prasad told us at the time, “Even with the energy downsides of high-rise, urban sprawl is a far worse option.”

While there are considerable challenges with high-rise sustainability, it pales in comparison to the challenges of suburban sprawl.

“Transport problems alone have enormous social and health effects,” he said. “People who travel long distances to work spend less time with their families and their health is impacted.”

Curtin University’s Professor Peter Newman agrees.

He told The Fifth Estate on Thursday that the transport emissions in car-dependent suburbs could be 3-4 times the operational energy of inside the home, though these were rarely taken into account.

“We’re finding these suburbs on the fringes are becoming poorer and poorer, and are using far more transport energy than any of the wealthy suburbs,” he said.

“It’s increasing inequity.”

Newman is currently working with the Intergovernmental Panel on Climate Change reviewing compact city literature, and says the opposite conclusion to the Domain piece was consistently being made.

“Compact city literature is extensive and completely opposite in its conclusions – you save energy, water and money for individuals and for cities in terms of infrastructure, and certainly [use] less land.”

He wasn’t impressed with the study (which was US based), nor how it had been portrayed.

“They compare a few hundred rich people living in high-rise top end apartments with a few hundred poorer families in the suburbs and find they use more energy on their spas and swimming pools, spend more time travelling (as they walk a lot) and they use much less water, then they say they are more environmentally damaging.”

As the report admitted, it wasn’t even comparing apples with apples, which is why there was more car ownership in high-rise than the suburbs (though per household it was much higher in the suburbs).

“It must be stated that this demographic skewing towards comparing predominately affluent, white, older/retired couples and singles in the high rise scenarios with affluent, largely white families in the suburban scenario, became a major limitation of this research program,” the report said.

So the case for high-rise living being worse for the environment than suburban sprawl doesn’t stack up too well – and that’s before we even start talking about infrastructure, habitat and biodiversity loss.

 Social benefits of city living

The Domain piece incorrectly linked to another of Wood’s reports, which funnily enough looked at life satisfaction of tall building occupants versus those in the burbs, and found that those living in inner city apartments had higher life satisfaction outcomes, which came down to accessibility of services and perceived safety.

Now let’s go back to some of those “bombshell” results. People living in high-rises are spending more time travelling? Well, it wasn’t because they were driving to work. It was because they were spending their time walking or riding their bikes; and because they spend a greater amount of time going to shops, restaurants and entertainment venues, and visiting family and friends.

City living doesn’t sound so bad, does it?

Though this isn’t to say there aren’t problems with high-density living, which is perhaps what Wood was trying to say. Take a recent webinar, for example, where he spoke of the “shortfall of tall”.

“You would expect someone in my position to be absolutely gung-ho – ‘tall buildings are great, great, great’ – but the reality is that 95 per cent of tall buildings are pretty terrible pieces of design.”

A look at some of the high-rises going up in Australia supports this assertion.

But Wood is still an advocate of denser living, so you’d assume the take-home message he wanted from the report was more “we need to do things better”, rather than “let’s not do high-rise”.

The other elephant in the room, though, is the case for compact medium-density living following a European model, instead of this obsession with super tall buildings. It doesn’t have to be a high-rise versus detached housing scenario. That missing middle is, well, missing.

So at best the Domain piece is incomplete; at worst it’s misleading, and could be used as fodder for those who would prefer our cities spread cancerously over our forests and agricultural lands, for a number of self-interested reasons.

Yes, tall buildings can have embodied and operational profiles higher than low-density housing. But they don’t have to. What about the Vancouver towers going for Passivhaus certification? Or one in the wings here in Australia set to produce all its own energy onsite (more on that later) and be built with low-carbon materials?

Tall (and perhaps more importantly medium-rise) buildings can be done well, respectfully and with low impact – without threatening native species, agricultural land, or increasing congestion and car dependence. Density isn’t the issue. It’s about how and where we build. Let’s not throw the baby out with the bathwater.

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  1. The density we need should provide urban amenity, a good relationship with neighbouring buildings, the street and the public domain more broadly. There’s nothing especially urban about tall towers – they are set apart, closer to a suburban model of isolated difference. What kind of streets are we creating?
    The target model for Sydney developers nowadays seems to start at 20 storeys, which will be disastrous for the urban character, and provide, in years to come, plenty of poor examples of how to do density badly.

  2. Ideas about tall buildings and density need to be decoupled. Paris, a low rise city, has over 20,000 people/km2, Barcelona has 16,000/km2. The city of Sydney has 8,300/km2, the broader Sydney drops to 400. Ben Driver from Hill Thalis, in a letter to the Sydney Morning Herald noted that “60 storey tower height is present only in a few parts of Manhattan, and completely absent in Paris and London. Density and amenity in these cities comes from the consistency of the buildings; four to six storeys, where each and every apartment has a relationship with its neighbours and the street. Streets keep their sunshine, and are supported by robust urban canopies. All the great cities in history have displayed this arrangement.”