Urban growth and decline
Australia is an extremely urbanised country. About 85 per cent of the population lives in coastal areas, and most of these people live in urban areas with populations of over 100 000 people. Together, these areas only comprise about one per cent of Australia's total land mass. This level of urbanisation has meant that many of our cities are facing enormous pressure to keep up with the needs of their swelling populations. Generally, since the trend towards urbanisation began in the second half of the last century, our cities have been in a constant state of 'catch up' with the needs of their swelling populations. See image 1
Major impacts of urban growth
Urbanisation has created many issues in Australian environments. While more people may translate to economic benefits, ever-expanding populations have brought with them a range of problems for both the physical and built environments. As our big cities have grown away from the centre to accommodate people's settlement needs, suburbs have mushroomed outwards, producing what is referred to as 'urban sprawl'.
This process means that the natural environment suffers as more space is required for the construction of houses and the development of industry. As more ecosystems are disrupted and habitats are destroyed, urban growth leads to an even greater reduction in the biodiversity of areas surrounding cities. The problems of pollution and sewage disposal are also made worse by increases in population size.
In terms of the pressures it places on the built environment, urban sprawl increases the monetary and environmental costs associated with infrastructure, waste disposal, the use of natural resources and energy consumption. It also has the potential to negatively affect the social cohesion of cities, as it often results in a lack of equity amongst urban residents, particularly in terms of access to infrastructure and other essential services provided by the city. Another impact is that, as fewer people live in the city centre, the quality of the original urban areas falls into decay. The process of cities expanding outward and then starting to deteriorate is known as 'urban growth and decline'.
Urban sprawl in Sydney
Sydney could really be considered as the heart of urban Australia. The population of Sydney is predicted to reach 4.9 million by 2026, up from 3.9 million in just 20 years. The Sydney Greater Metropolitan Region (GMR) now extends from Port Stephens in the north to Kiama in the south. Some townships in the Blue Mountains, now also considered part of the Sydney GMR, are between 50km to 120km west of the Sydney CBD. Since 2000, however, Melbourne, Perth and Brisbane have recorded higher rates of population growth than Sydney. See image 2
Urban and human ecological footprints
In order to assess the sustainability of a population, geographers sometimes use the ecological footprint (or eco-footprint) model. This determines the impact that a defined human population (for example one person, a city or a country) has upon its surrounding environment. See animation 1
An urban ecological footprint does this by providing an approximation of the total amount of land required by a city, to provide it with the resources it needs to sustain its population. In addition to accounting for the food, water and other natural resources people consume, the footprint also includes the space required to dispose of all the waste they generate. In a study conducted in 2005, it was estimated that Sydney's ecological footprint covered 49 per cent of NSW. It was also predicted that if current rates of growth continued without any drastic action being taken, the footprint would cover about 95 per cent of NSW by the year 2031.
The human ecological footprints of individuals within a defined geographical area (such as a country) can also be calculated. The higher a country's human ecological footprint is, the less-sustainable its population is. The Australian population has an extremely large ecological footprint compared with other countries around the globe, which is indicative of our unsustainable consumption patterns, and reflective of the impact we have upon our surrounding environments. Our ecological footprint is in fact the eighth highest in the world, at 7.4 hectares per person (ha/p). In comparison to this, the ecological footprint of the USA is 9.7 ha/p and in Africa it is only 2.1 ha/p; the global ecological footprint is about 2.3 ha/p. See image 3
Major challenges presented by urbanisation
Intense urbanisation has presented Australia with many environmental challenges which governments have tried to respond to with policies aimed at achieving 'urban consolidation' or 'urban renewal'.
Resource and energy challenges
Larger cities demand more energy and place more strain on our already scarce natural resources, such as water and energy. In Australia, our already unsustainable household energy consumption levels are alarmingly on the rise. Urbanisation fuels this trend even further as larger populations need to be supported by more sophisticated infrastructure, which in turn demands more electricity. This is a problem in Australia as we are currently dependent upon using non-renewable fossil fuels, namely coal, oil and natural gas, for almost all of our energy needs.
The process by which urban areas sprawl outward places increased pressure on governments to keep up with the population's infrastructure needs. These needs include access to amenities such as quality housing, transport systems, roads, schools, hospitals and police and fire services. These are all fundamental parts of our everyday lives, without them we would be unable to maintain our generally high quality of life Australia. Urbanisation also demands more emphasis be placed on social infrastructure, such as community centres, youth centres, parks and sporting fields, so that our urban areas can maintain their social cohesion.
Social cohesion and equity challenges
Social cohesion can be defined as the level to which people in a society feel committed towards the well being of others, and to the shared systems which form the foundations of the society. Although many people migrate to cities to find more or better employment opportunities, urbanisation usually brings higher unemployment rates and subsequent increases in criminal activity. This type of anti-social behaviour, along with vandalism and a lack of respect for public property, often symbolise a reduction in social cohesion.
These problems are heightened by the isolation often felt in poorly-serviced fringe suburbs (dwellings on the outskirts of cities), which tend to become neglected. As they have less access to the benefits of the city (including employment opportunities, shared public places and other forms of infrastructure), suburbs on the outskirts often reflect the lack of equity inherent in many major metropolitan areas. Often they also have a higher level of poverty, which is one example of how urbanisation can lead to increased levels of spatial inequality (refer to Chapter Three).
The need for 'urban renewal' and 'urban consolidation'
To counteract the many challenges created by urban decline, governments have started to introduce housing and planning policies aimed at achieving 'urban renewal or 'urban consolidation'. These terms describe how planners have begun trying to halt the spread of populations outward into fringe suburbs, by focusing on rejuvenating buildings, roads and public spaces that have gone into decline closer to the city centre. This planning strategy can decrease some of the infrastructure and equity problems previously discussed, by allowing more people to access the services provided in the city.