State of the Environment 2011 Committee. Australia state of the environment 2011.
Independent report to the Australian Government Minister for Sustainability, Environment, Water, Population and Communities.
Canberra: DSEWPaC, 2011.
10 Built environment
At a glance
The resilience of the built environment to the pressures on it — in terms of the impact of these pressures on livability and urban environmental efficiency — is variable. The built environment is generally not resilient to pressures arising from growth, particularly population growth, but is more resilient to pressures associated with weather-related events.
The approach to assessing resilience in this section is the same as that used in the rest of the report. Resilience for the purposes of State of the Environment reporting is defined as 'the capacity of a system to experience shocks while essentially retaining the same function, structure and feedback and therefore identity'. For natural systems, this approach works well. For human systems, such as the built environment, functionality, structure and identity are constantly changing, so describing and gauging resilience is difficult. Some shocks may alter the structure and identity of the built environment, but some may consider that responses to these changes, while not restoring the original structure and identity, may not always be undesirable and in some cases may increase livability.
An increase in the urban footprint brought about by population growth fundamentally alters the structure of a city and can have significant impacts on its identity, many of which would be seen as negative. Urban sprawl can reduce livability and environmental efficiency, and can have an irreversible impact on the natural environment (e.g. due to land clearing). However, if population growth occurs in areas that are in decline or where land is underutilised, and the development is done in a way that preserves quality green spaces, the impact of the growth is much less significant.
Increased traffic congestion arising from population and economic growth can significantly affect the function of a city. Some of the ways in which this might be mitigated (e.g. building additional roads) impact on the structure and possibly the identity of the built environment. On the other hand, growth in traffic congestion can be mitigated through increased use of public transport, which has a much smaller impact on the structure and identity of the built environment.
Pollution may lead to an increase in episodes of poor air quality. The frequency, duration and severity of these episodes are influenced by short-term meteorological conditions and local topography, and air quality is usually restored to acceptable levels once the immediate conditions change. However, human resilience in the face of prolonged or recurring exposure to air pollutants is limited.
The resilience of the built environment in the face of increased consumption depends on the extent to which the built environment system itself leads to increases in efficiency. There are mixed views on whether urban systems create efficiencies in the use of environmental resources; many improvements in environmental efficiency tend to result from factors 'outside' the system, such as changed behaviours and technological improvements. In this regard, the built environment itself could not be considered resilient to increased consumption. However, where development and redevelopment activities in urban areas use 'green' building techniques and are associated with better infrastructure and services, the environmental impact of increased consumption can be significantly reduced.
Generally, the built environment is quite resilient to extreme weather events. Cities have a very good capacity to 'bounce back' from these shocks, particularly following rebuilding and other recovery activities. However, in some extreme cases, the structure and identity of the built environment might alter as a result of an extreme weather event, and there may be long-lasting effects on urban amenity. Higher sea levels would have a more lasting impact on affected built environments, particularly if there is a structural response in areas at risk of inundation.
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