Monday, February 23, 2015

Melbourne Heat Island Effect

Last year I did research into, and gave speeches about, the public health benefits of public open space. My view about the importance of this is reinforced by recent statements in the Moreland Leader by University of Sydney Associate Professor Tonia Gray that research shows that neighbourhoods with more green spaces are much healthier and socially cohesive. She says, "Nature has a calming effect, it recalibrates your body. Australian kids spend an average of 52 hours a week in front of a screen but an average of 40 minutes outside".

The importance of trees and vegetation cover is also reinforced by research calling for Melbourne suburbs to increase their tree cover to combat rising temperatures. The urban heat island effect occurs when built-up areas with surfaces such as roads, concrete and buildings absorb heat on hot days. It is dangerous to public health. In 2013 and 2014 over 400 Victorians were admitted to hospital for heat related illness. Researchers say "heat islands" are only going to get hotter unless more green spaces are incorporated.

Given this, it is folly to allow dual occupancy, multi-unit and high rise developments to lead to the cutting down of trees and shrubs and the paving over of open spaces which are presently cooling Melbourne down. We need to push back against plans by property developers and council officers to allow more buildings in what are already built up suburbs.


  1. Property developers and the Government encourage Councils to accommodate the growing population through a combination of infill and redevelopment in existing urban areas, usually high- and medium-density developments, as well as green-field developments.
    However, surveys show that close to 80% of the population desire a detached house and garden, not town houses or apartments. The high cost of Australian housing constrains many from their dream, however.
    There are many disadvantages with higher density living :
    a. Attractive suburbs with flowers and foliage are being overrun by concrete and bitumen. Bewildered long-time residents find themselves in the shadows of unit blocks.
    b. Greenhouse gas emissions increase. Studies show that energy use in high density housing is about twice that for a detached house.
    c. The per-resident energy to construct high-rise is nearly five times that needed to build a house.
    d. Research in Melbourne shows people squeezed into newly converted dense areas did not use public transport to any greater extent and there was little or no change in their percentage of car use.
    e. There is not enough difference in the emissions of public versus private transport to counter the increased emissions of high-density living. For each kilometre CityRail carries a passenger, it emits 105 grams of greenhouse gases, while the average car emits 155, and modern fuel-efficient cars such as the Toyota Prius emit just 70.
    f. Increased congestion caused by high density damages health. Vehicle exhaust contains micro particles that kill 3 million people each year, the World Health Organisation says. High density is also bad for mental health. A study of more than 4 million Swedes showed the rate for psychosis was 70 per cent greater for dense areas, and there was a 16 per cent greater risk of depression. The Australian Unity Wellbeing Index shows the happiest electorates are those with lower population densities.
    g. Adding more people to existing infrastructure means overload. The standards of Sydney's roads, rail, water supply and electricity have all deteriorated from the imposition of high-density policies.
    h. The effect of high-density policies on the cost of housing has been devastating to our younger generation. By trying to force people into higher density on existing land, the supply of new land for housing has been cut. The cost of land now comprises 70 per cent of the cost of a home, instead of 30 per cent as it used to. A new dwelling should cost about $210,000 but is closer to $500,000.
    i. Bureau of Statistics figures show 83 per cent of Australians prefer to live in a free-standing home, and we do object to draconian policies forcing us to live in bland high-rise units.
    A particular disadvantage of higher density developments is the heat island effect. A study into this effect has been done at Monash University, Melbourne. The study concluded, in part, “that a move toward a more compact city with built-up activity centers ... would raise urban surface and within canopy temperatures, leading to unfavorable conditions, in particular for those with increased vulnerability to excess temperatures. ... A move toward a more compact city will extend the seasonal exposure to unfavorable climatic conditions, with warmer temperatures expected in the shoulder months on either side of summer.”
    Where the capacity of services needs to be increased to cope with redevelopment, the cost usually exceeds that for providing the services in a new development. Increasing the population density allows a more cost effective provision of services only where the existing services can cope.
    However, overall, increasing the population density is not cost-effective; the disadvantages significantly outweigh the benefits.
    The present population policies of Government will cause more and more crowding, contrary to the desires of most people. This will create less healthy and less liveable communities.

    Lindsay Hackett.

  2. Neighborhoods with a lot of green space are also probably more stable places to live in, with more consolidated social networks and civic participation. The neighborhoods without much green space are usually high resident turnover places where increasing density affects street lay-out, council rates, and choice, leading to alienation and anxiety. In dormitory suburbs newer populations are likely to be struggling anyhow. Urban heat islands obviously increase the stress. Not having the opportunity of associating with nature beyond human society is a sad thing. The lack of green space also points to a reduction in the commons available, particularly to women, children, the elderly and the unemployed. The commons are where we meet our neighbours and form political relationships with each other. It is all a symptom of overpopulation, which is being encouraged by bad governments, oppositions, and their corporate friends. Thank you for standing up to this, Kelvin.


    1. The following letter was sent to The Age on Jan 6th 2015 as a reply but was not published. It can have an airing

      "It is not only trees in parks that, through leaf transpiration and shade, lower summer temperatures in our cities. (City Parks invaluable – V.McKenzie McHarg ACF 6.1.15) The same cooling attributes apply to trees in private gardens and from which all neigbouring residents and local pedestrians benefit. Trees in parks and trees in private garden are all part of the local urban environment and its leafy canopy. Unfortunately, the drive for endlessly higher population and the consequent need to accommodate about 90,000 additional population each year in Melbourne, much of this within existing suburbs, necessitates the removal of gardens and trees to redevelop throughout the suburban area. We cannot help but have increased “urban heat island effect” whilst suburban tree density is reduced and buildings and paving are increased. For any hope of maintaining a resemblance of present levels of livability in its cities, Australia needs to aim now to stabilise its population in the near future.

  3. No wonder I like getting out on the golf course !!

  4. Last year I made a trip back to the neighbourhood where I grew up (Mangere, Auckland, NZ). Back then, it was a diverse mix of 1/4 acre suburban lots, farms, and commercial gardens. It was a fine place to be. Now it has all been subdivided and the subdivisions have all been subdivided again. It is a remarkable thing that so many people cram themselves so much.

    And still the place reeks of propagandizing by development-rats... Like Melbourne (a place I also used to live and love), Auckland has become mired by unprofitable, inhumane growth. Clagged.