How mass immigration makes our cities hotter

For years, the development industry and urban planners have called for Australia’s supposedly underutilised middle-ring suburbs to be bulldozed for apartments and townhouses in order to house the many millions of extra migrants projected to inundate our cities over coming decades:

This transformation into a dense urban form is to be most stark in Sydney, where the Urban Taskforce projects that only one quarter of dwellings will be detached houses in 2057, down significantly from 55% currently:

This transformation will also see reduced access to green space, according to Infrastructure Australia’s modelling, as Melbourne’s and Sydney’s populations balloon to a projected 7.3 million and 7.4 million people by 2046 (see last highlighted row below):

An issue conveniently ignored by these planning geniuses is that in addition to eroding all markers of liveability (see above), their urban infill utopia will also make our cities hotter, causing increased heat-related deaths.

With canopy coverage declining across almost every city, researchers last year sounded the alarm:

Australian cities are increasingly becoming concrete jungles as trees and canopy coverage disappear, according to experts who warn this is contributing to an urban “heat island” effect…

It has estimated this can create on-ground temperatures as high as 55 degrees in the sun.

Compounding the issue, a 2017 report by the group, titled Where Should All The Trees Go, found canopy coverage in urban areas had declined in almost every state and territory…

Yesterday, The ABC warned that urban infill will bake our cities under concrete:

It’s a familiar sight across many Australian suburbs.

Demand for housing has led to a rise in subdivisions, and a loss of yard space and the trees they contain.

Block sizes for new houses across Australian cities have plummeted by 22 per cent — to an average of 467 square metres — in the past 15 years, according to the Australian Bureau of Statistics.

In Melbourne alone, about 240,000 new lots — including houses and units — have been created since 2015 as a result of subdivision…

Gregory Moore, a senior research associate at the University of Melbourne, has been studying Australia’s declining urban canopies.

“In most Australian cities, the density of the canopy cover is diminishing at various rates,” Dr Moore said…

“Nearly all of the change is happening on privately-owned land … and most of it is the redevelopment of large blocks into smaller blocks or into townhouse developments.”

The trend is exacerbating an urban heat island effect, where hard surfaces like concrete and steel absorb and then release heat.

Trees and the shade they provide can help reduce the impact, but stripping away that canopy accelerates the effect.

It can make our cities 4–10 degrees Celsius hotter than surrounding rural areas, according to research from RMIT’s Sustainability and Urban planning program.

Associate professor Joe Hurley and his RMIT colleagues have mapped vegetation loss in a number of Australian cities.

They found several outer suburbs in Melbourne and Sydney were most vulnerable to the heat island effect.

“Areas like the western suburbs of Sydney and the western suburbs of Melbourne, where we see lower socio-demographic factors, we also see lower vegetation and higher susceptibility to heat,” Dr Hurley said…

Anoop Sud lives in Stanhope Gardens in Western Sydney, and has seen it rapidly develop over the past 11 years.

Having migrated to Australia from India, Mr Sud said he was used to overpopulated cities, but now felt “claustrophobic” because of the number of houses and people.

As his neighbourhood becomes more crowded, he is finding it harder to escape the extreme heat — in February last year, temperatures soared to 44.5C, and Mr Sud found it difficult to breathe.

Dr Tony Matthews – a senior lecturer in urban and environmental planning at Griffith University – has been at the forefront, explicitly warning that infill development is driving the heat-island problem:

“Heat stress actually causes more deaths in Australia than all of the other natural disasters combined”…

Middle-ring suburbs were more likely to be the leafy, cool retreats created by postwar architecture and planting…

“The real problem comes when we try and increase densities, which we have done in a suburban context through a quality called urban consolidation,” he said.

“And that has been taken up through most of the capital cities, all of the capital cities, in fact.

“It’s squeezing more floorspace out of less land, so that’s why we’re seeing so many apartments, so many townhouses, we’re also seeing a reduction in block sizes from maybe 700 metres or 650 metres to 400 metres.”

Squeezing more properties onto land means there is less room for parks, trees, or anything other than constructed buildings, he said.

The result is dense, urban fringe suburbs with little greenery and houses with no gardens, parks reduced in size as competition for tenancy grows…

“What I feel we have done with these suburbs is we have locked them into a pattern of heat stress, limited outdoor activity, limited use of the public realm, and all of the problems that come with that because they’re not green enough and in some cases they don’t have the potential to be any greener,” Dr Matthews said.

The infill utopia of jamming millions more people into the existing urban footprint will necessarily chew-up green space as backyards, trees and open space are removed to make way for additional dwellings. And this will necessarily exacerbate the ‘heat island’ effect afflicting our cities, in turn raising energy use (think air conditioners).

Clearly, maintaining green infrastructure in our major cities is not consistent with the projected explosion of their populations via mass immigration, along with planning rules that force increased population density.

The first best solution to this problem is to slash immigration back toward the historical average, thereby slowing the destruction of green space.

Sadly, the latest Intergenerational Report projects that Australia’s population will swell by 13.1 million people (~50%) over the next 40 years on the back of extreme immigration of 235,000 people a year. This is the equivalent of adding another Sydney, Melbourne and Brisbane to Australia’s existing population:

Australia's projected population growth

Stop treating symptoms and address the problem at its source.

Unconventional Economist
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  1. UpperWestsideMEMBER

    The whole point to developing the middle ring is that is where the maximum profit is to be found
    But you need to make sure its coordinated with the govt.
    You need all the ‘mates’ to get development approved about the same time so you can flog the dog boxes off the plan while its still nice an green and desirable
    You dont want to be trying to flog crap when the punters can see just how charmingly 4th world (minus the charm) the final result will be.

    • Arthur Schopenhauer

      It’s only better if the implementation is well executed. Berlin, Hampstead, maybe Vienna. High density with care.

      New York, very high density with the dumb luck of making a huge park in the middle. Not great.

      The urban planning in Australia is leading to Jakarta or Bangkok style dysfunction.

      Like anything, the quality of an idea is all about execution.

      • Agreed. In Europe they limit the height of buildings, and improve the density by having their cities walkable, rideable, and with good PT. We’re following the American/Asian model which leads to dysfunction.

      • Europe, especially Northern Europe, doesn’t have Australia’s summer sun. Much harder to compare. In cooler climates with a lot less direct sun less energy in means you need less cooling capacity to maintain normal temps.

        Not apples to apples comparison.

        • Spain or Italy would be fairly comparable. Rome regularly in the 40s. Actually amazing how pleasant the old architectural buildings are in that heat.

    • Arthur Schopenhauer

      As for sprawl. The biggest problem is servicing lots, and maintaining a large distributed infrastructure. Currently suburbia needs a lot of energy (money) to operate.

      However, decouple power from the grid, electrify road transport with light weight evs, remove telecommunication cables with wireless, locally store storm water , shift work away from commuting and that only leaves sewage and potable water.

      Suburbia very quickly becomes a much cheaper proposition.

      High density cities are the physical embodiment of inequity.

      • ErmingtonPlumbingMEMBER

        Around a third of the houses in Ermo were built before the sewer went in in the mid 60s.
        Heaps of 50s and early 60s houses (not to mention the few earlier builds) got built after the water and power got run in.
        My 96 year old neighbour had a dirt road out the front for the 15 odd years he waited for the sewer to be brought through.
        Every house in the street had a bathroom like mine with a Pink or Blue bath, basin and small stepped hob shower that along with the Kitchen Sink, via a little grease arrester, was plumbed into an absorption trench in the front or back yard. These Trenches are basically 2 brick wall around 600 high and 5 or 600 apart with a thin concrete lid that’s usually 4 or 500 under the grass.
        The sh!thouse was out side and had a standardised sized can that got replaced by the “Dunny man” at frequent intervals.
        When my neighbour finally got hooked up to the sewer 15 years into living here he like most others in our street built a rear extension to the house with a laundry and toilet in it.

        It was the first time old mate had ever lived in a house with an indoor toilet (he must have been in his 30s) and told me it took him years to get used to taking a shyte inside as he thought it,…a filthy thing to do inside the house!
        I still occasionally come across these old out houses in peoples back yards that got plumbed up to the sewer when it Finally arrived.
        Those redundant Absorption trenches usually just got disconnected and left in the ground and forgotten but occasionally someone would hook up the stormwater into them or as I discover about once a year left the kitchen line hooked up into it, over 50 years ago! By the plumber who hooked up the bathroom to the sewer but left the kitchen line still going to the absorption pit/trench.
        When I’m discovering this while trying to jetblast through a blockage it’s always a pain in the ar$e for me and expensive for the owner if the thing is finally silted up.
        Still 60 years of continuous service is good value.
        Don’t know if we can expect the same life outa PVC.

        Of course the difference today is that everything has to be front end loaded which also adds to the cost of home ownership. Especially when green field land release basically requires a developer to take full responsibility for this front end loading. They thus become a cartel and take control of the market.
        For example Old mate neighbour built the second house in our street around 1950 and yet the subdivision drawings I got a copy of when I purchased my house next door to his was stamped by Parramatta Council in 1922!
        28 years before people started building permanent dwellings. Obviously people didn’t start building until the Water and Power went through this 50 odd acres of 3 by 2 streets. But these 600m2 average sized blocks were purchasable, very cheaply I assume, and in a way into home ownership that just isn’t available to young people today.
        Land owners can’t do these subdivisions without a rapacious profit driven developer today.

        I asked old mate if all these blocks we’re fenced off before people built on ‘em.
        Some were, some weren’t. There were 3 blocks in a row that had vegetables growing market garden style he said.
        Some were covered in weeds, a lot had a horse or couple of goats.
        He reckons 10 years after he started building 80 to 90% of the blocks around here were built on. Before the sewer went in.

        • Arthur Schopenhauer

          Thanks for that Ermo. We found a number of our terracotta storm water pipes stopping in the middle of the very swampy parts of the garden. For the past 70 years, they drained into the garden!

        • Brings back memories. My parents house was built before the sewer went in. I remember the dread of having to use the thunder box out the back. The stink on a hot summer day was horrendous but the chokes grew well over the roof. I also remember the ‘dunny’ man coming around the back of the house to collect the can and his truck stunk. What a job!
          We also has the grease pit at the side of the house.
          And you are correct about front loading all the costs of services onto the buyer, Back then you could buy a bare block of land and gradually the services came and the costs were spread over a number of decades.

  2. reusachtigeMEMBER

    I’ve been to Adelaide and they aren’t very hot down there so could do with the improvement!

  3. Arthur Schopenhauer

    One of the key issues is site coverage.

    The Victorian medium and high density rules allow 80% plus site coverage. No room for trees, large or small.

    It’s pretty basic stuff.

      • Arthur Schopenhauer

        You missed the point. It is possible to build the same floor space and cover 50% of the land, by building taller. Building orientation and street width become an issue, but it is very possible.

        In 18th/19th century cities like Paris, Berlin and Vienna, the plot ratio (site coverage to total floor area) leaves large amounts of green space inside the block.

        So, I agree that people will build to whatever the planning scheme allows.

        We need more sophisticated planning schemes
        that leave room for trees. Dumb idea that works, yet incredibly hard to execute.

        • I get it. But it doesn’t address the core issue of bulldozing the middle ring suburbs to cater for ‘growth’. Many lots in my area have been subdivided into two storey townhouses. Sure, they could go to three storeys instead with smaller land coverage, but that would raise building costs significantly. Also, who wants to be overshadowed by a three storey building? And who wants to climb another set of stairs?

          • Arthur Schopenhauer

            Agree with you completely. We are in the same position just north of the Yarra. Our neighborhood is being destroyed by poor high density buildings too.

            Hampstead in London is a high density suburb, skillfully executed. It balances a mix of housing types, work spaces and green space, and as a whole it is a very pleasant place to live.

            The construction in and of itself is not more expensive than other construction of its time, but the care taken in sheparding the suburb to realization was very high.

            We have no care in Australian construction industry
            at the moment.

          • It’s a sad state of affairs when the quality of modern homes is often worse than homes built in the 50s and 60s.

            I’m lucky to live in a 1940s solid brick home that is built so well that it could stand for hundreds of years. But my house is the minority.

        • blindjusticeMEMBER

          Losing roof space is ok in Europe, to some extent, but in Australia you can maximize rain water collection and solar power

    • Yes, of those “only 1 qtr of houses will be detached” many will likely be built just a foot or two from the one next door (is that really detached?) so big heat island, especially as they also don’t like trees these days due to root damage etc, trees being one of the most effective forms of cooling due to evaporation.

      • Arthur Schopenhauer

        A real issue for western Sydney, and Brisbane. Melbourne has a heat problem in places with a massive build out of apartment buildings, like Brunswick.

        • Brisbane used to have pockets of subtropical vegetation. Like the cultural cringe the blowins thought it too native and now we’ve got fibre cement jungles.

  4. Last week we were being told that replacing old housing with new saves energy.
    Now we are being told the opposite.
    I can’t keep up.

  5. Sitting on my front window looking at yonder cows and the neighbour’s magnificent jacaranda set against storm clouds scudding low across the sky, I thought how good it would be to decrease my mowing by concreting some of the 500sqm front lawn, turning it into a mixed use area of BMX/skate area plus overly-complicated mini golf. Can-do concreting.

  6. One is sure that local, state and federal governments would also like to blame the supposed ‘mass immigration’ for heating our cities and avoiding any responsibility and accountability? Why do media make it so easy for the powers that be?

    You are giving them an excuse to do nothing, like on carbon emissions, by blaming headline ‘immigration’ &/or NOM numbers without showing any direct correlation with heating. How can good policies for all, including the environment, be developed if complacency or inertia is encouraged and supported on urban planning, infrastructure, green areas, residential construction, renewable energy sources. state investment etc.? Leave it to the market?

    Related, an investment analyst warned middle aged Australians from investing or buying into residential property as growth in real terms is tepid and one’s primary residence does not pay retirement income; backgrounded by ageing and declining permanent population.

    Maybe lots of (in real terms) cheap residential properties will be flooding the market over the next 15 years as baby boomer ‘bubble’ transitions, inc. downsizes/aged care, with no guarantee of any return to growth in the NOM while skilled migration is relatively modest (in a workforce of 13 million+)…… look out….

  7. Leisha JackMEMBER

    It gets worse! According to the Lancet heat-related deaths are seriously under-reported. Death certificates do not require that environmental factors such as temperature be mentioned in the cause of death.

    See articles below:

    We know that heat kills; accurately measuring these deaths will help us assess the impacts of climate change (Australian National University)

    Heat-related mortality: an urgent need to recognise and record (The Lancet)

    Governments have known for decades about the Urban Heat Island Effect and the danger to human health from extreme heat. Their inaction on introducing laws to protect greenspaces and mature shade trees to protect citizens is like their inaction on stopping the tobacco and fossil-fuel industries.