One of the main drivers of environmental change identified in the Drivers report is population growth (Figure BLT2). Population and economic growth present both opportunities and challenges to our built and natural environments. Opportunities relate mostly to the economic activity that enables jobs and services, as well as some environmental opportunities such as recycling and public transport. Growing communities place pressure on existing infrastructure networks and services such as water distribution; waste removal, treatment and disposal; and transport (Infrastructure Australia 2016). In addition to pressure on infrastructure, growing communities also need places to live, work and recreate, which puts more pressure on the availability and quality of open space and the natural environment, and increases potential risks to human health. As the urban population grows, additional urban land is required, or existing land is used more intensely.
Increased urban footprint
Increased urban footprint
The location and density of population growth affect the urban footprint. In Australia, the capital cities account for most of the nation’s total population growth, and population growth tends to be most concentrated in outer suburbs, inner cities and some urban infill areas, and along the coast. Areas that have declined in population in recent years include regional areas and some long-established middle suburbs within capital cities (ABS 2016a).
At 4.92 million people in 2015, Greater Sydney continues to be Australia’s most populous city, followed by Greater Melbourne at 4.53 million. Next is Greater Brisbane (2.31 million), Greater Perth (2.04 million) and Greater Adelaide (1.32 million), followed by the smaller capitals of Canberra (391,000), Greater Hobart (221,000) and Greater Darwin (142,000) (ABS 2016a).
Between 2011 and 2015, the population of Greater Perth grew by 11.2 per cent, followed by Darwin (10.2 per cent), Greater Melbourne (8.6 per cent) and Greater Brisbane (7.5 per cent). Greater Sydney’s population grew by 6.8 per cent in the past 5 years.
Generally, the most prominent growth outside of capital cities between 2011 and 2015 occurred along the coast of Australia, particularly in Queensland. The population of regions of the Gold Coast (Ormeau–Oxenford) increased by just under 20 per cent between 2011 and 2015, whereas Gladstone–Biloela (Fitzroy) increased by more than 11 per cent. Areas of the Sunshine Coast also experienced growth of around 9 per cent (Buderim, Caloundra).
In Western Australia, large growth occurred on the state’s south-west coast. Augusta – Margaret River – Busselton grew by nearly 15 per cent in the past 5 years, and Bunbury grew by just under 10 per cent.
In Victoria regional areas around Geelong (inland) also experienced significant growth, including parts of Barwon-West (Bannockburn—23 per cent), and Grovedale, Highton and Lara (all around 10 per cent). In New South Wales, the inland region of Maitland (in the Hunter Valley) also grew by 10 per cent (ABS 2016a).
Capital cities and density increase
Australia’s urban population is unusually concentrated in 2 large cities (Melbourne and Sydney). These and the other large cities have unusually low population-weighted density compared with cities in other developed countries with similar population sizes.
Greater Sydney has Australia’s highest population weighted density1 at 3647 people per square kilometre (km2), followed by Greater Melbourne at 2746 people per km2. This is followed by Greater Perth (1992 people per km2), Greater Brisbane (1910), Greater Adelaide (1893), Canberra (1661), Greater Darwin (1537) and Greater Hobart (1172). Global comparisons of such urban density are London (5880), Vienna (7030) and Houston (9200) (Newman & Kenworthy 2015).
Except for 4 medium-sized (statistical area 2; SA2) regions in Brisbane, the 100 areas with the highest population-weighted density across Australia’s capital cities are all in Greater Sydney or Melbourne. Between 2011 and 2014, Greater Melbourne experienced the highest increase in population-weighted density of all the capital cities, closely followed by Sydney, then Perth (Figure BLT3).
The regions (SA2s) with the largest recorded increases in population-weighted density in Australia between 2011 and 2014 were all in inner Melbourne—Melbourne had the highest increase, followed by Southbank and the Docklands. Other large increases in population-weighted density in inner Melbourne were recorded in Carlton and Fitzroy, to round out the top 10 largest increases in Australia. Outside of inner Melbourne, significant increases for Greater Melbourne occurred on the northern fringe of the city around Craigieburn–Mickleham, Epping and South Morang, and in south-east Melbourne (Cranbourne West and Cranbourne East).
Pyrmont–Ultimo and Waterloo–Beaconsfield in inner Sydney experienced the largest increases in population-weighted density for Sydney, closely followed by Parklea – Kellyville Ridge in Sydney’s north-west. Along with inner Melbourne regions, inner Sydney areas (City, Inner South and Inner West) dominated the largest population-weighted density increases across Australia’s capital cities, with large increases also occurring in the Sydney–Parramatta region (Parramatta–Rosehill and Homebush Bay – Silverwater).
Much of the population-weighted density growth in Greater Sydney and Greater Melbourne can be attributed to strong activity in infill development in the inner city areas, and these areas (inner Melbourne, Southbank, the Docklands and Carlton in Melbourne; and Pyrmont–Ultimo and Waterloo–Beaconsfield in Sydney) are characterised by high population-weighted densities of between 7000 and 13,000 people per km2. Urban infill is the development of a site within an already developed area, either by building housing on land that was previously vacant or used for nonresidential purposes, or by replacing low-density housing with higher-density dwellings (ABS 2016a).
Medium-density to high-density development within established urban areas provides a viable mechanism to meet the needs of rapidly growing urban populations (Infrastructure Australia 2016). The substantial inner-city growth across Australian cities means less impact on greenfield areas in terms of land taken up, and per-person use of transport and building energy. It also has economic efficiency gains; hence, this trend helps convert population and economic growth into a reduced per-person footprint. However, increased densification and urban infill need to be carefully planned and managed to maintain adequate green space and green infrastructure as cities’ populations increase (see Natural environment and Planning for the future).
Not all the largest population-weighted density increases occurred in the inner areas, however. For Greater Perth, Baldivis and Bertram–Wellard in the south-west, and Ellenbrook in the north-east showed the largest population-weighted density increases. These population-weighted densities were lower than in the high-growth areas in Sydney’s and Melbourne’s inner-city areas.
Many areas that experienced strong population growth were located on the fringes of capital cities, where more land tends to be available for subdivision and housing development (see Housing). Between 2011 and 2014, 6 of the 10 regions with the largest population growth in Australia were outer suburbs of Greater Melbourne (see Box BLT1). South Morang, on the northern outskirts of Melbourne, had the largest growth in the country during the past 5 years. Point Cook, on the south-western fringe, and Craigieburn–Mickleham in the north, had the next largest growth. Although these areas have high growth rates, they have significantly lower population-weighted densities than the inner city areas (between 1700 and 3500 people per km2).
The next largest growth in population occurred in Western Australia. The region of Baldivis, on the south-western outskirts of Greater Perth, recorded the largest growth in the state between 2011 and 2014, followed by Ellenbrook in the north-east and Forrestdale – Harrisdale – Piara Waters in the south-east.
The Greater Sydney region with the largest population increase was Parklea – Kellyville Ridge in the north-west growth corridor of Greater Sydney, followed by Concord West – North Strathfield (inner west) and Homebush Bay – Silverwater (Sydney–Parramatta region).
In Greater Brisbane, the largest growth occurred in Springfield–Redbank (Ipswich area) and Caboolture (Moreton Bay – North).
Outer suburban areas in the smaller capital cities also had some of the strongest growth in their states or territories. In the Australian Capital Territory, the newly developed northern suburbs of Bonner, Casey, Franklin and Harrison (all in the Gungahlin area) had the largest population growth between 2011 and 2014, with population-weighted densities ranging from 1800 to 2300 people per km2.
In Greater Adelaide, the largest growth was in the outer Adelaide regions of Seaford (south) and Munno Para West – Angle Vale (north).
The shaded regions in Figure BLT4 represent areas that had significant new urban residential growth between 2011 and 2014. The Melbourne central business district and Melbourne outskirts have experienced the largest increase in the counts of urban residential parcels in the country. Greater Sydney recorded the second largest increase in the number of urban residential parcels. In addition, regions are shown where the number of rural-sized parcels has decreased and the number of urban residential parcels has increased, indicating where nonresidential (predominantly rural) land is being converted to predominantly residential. These areas are typically on the fringes of cities, reflecting the pressure that urban growth is placing on surrounding rural and agricultural land.
Despite strong growth in the inner areas of our major cities, the continued expansion of Australia’s cities through greenfield development means that the outer suburbs of our cities are also increasingly taking land away from farming and habitat for Australia’s biodiversity (see Box BLT1 and Figure BLT4). These greenfield developments can be distant from major employment centres, with resulting long journey times, high transport costs, high infrastructure connection costs for taxpayers, and negative social and environmental consequences (Infrastructure Australia 2016). Additional planning to mitigate these pressures will be needed.