3.2.1. Sustainability, sustainable development and urban sustainability
The Brundtland Commission (1987 p1), formerly known as the Report of the World Commission on Environment and Development, defined sustainable development, and sustainability as “meeting the needs of the present without compromising the ability of future generations to meet their own needs”.
The Australia State of the Environment Report (1996) defines urban sustainability as development that reduces resource inputs and waste outputs whilst simultaneously improving livability. Australia State of the Environment Report (2006 p127) defines a sustainable activity as “able to be carried out without damaging the long-term health and integrity of natural and cultural environments”. Sustainability requires society to function and exist within boundaries of Earth‟s capacity to function and provide materials, and within its capacity to process or accept our waste products and pollution (Halliday, 2008, Mobbs, 2001). Above all, sustainability gives us the message that humankind must:
achieve more, using less, for longer;
reduce both our consumption of resources and our production of waste; and
disengage links between resource consumption and waste production, and quality of life and wealth (Newman, 1999).
In terms of sustainability, it is therefore the job of housing designers, environmental practitioners, and planners alike to create urban and suburban environments that employ and consume less energy, water, materials, and land, and similarly generate less waste. CO2 is of particular concern and its production in Australia is directly linked to
energy use. These achievements must be made, while sustaining and improving the quality of lifestyle, housing and communities (Mobbs, 2001, Newman, 1999). Sustainability can be considered as a broad umbrella that covers the goals and objectives of this research, as well as providing environmental, social and economic motivators, benefits and rewards.
3.2.2. Social, economic and environmental aspects of sustainability
Newman (1999) argues that the environmental aspects of sustainability cannot be considered separate from social and economic matters, and that urban sustainability involves a juncture of economic energy/environmental and human concerns. Sustainability provides environmental benefits, including `the reduction of resource consumption, pollution, and waste production, and the minimisation of damage to threatened species and habitats. Social benefits of sustainability, and mechanisms to achieve sustainability, are interlinked with environmental gains, and include:
increased public participation and community engagement;
greater social amenity, wellbeing, and safety;
social equity and accessibility;
regional responsibility and leadership;
social and ethnic diversity; and
improved social infrastructure, services and facilities.
Consumption is costly, and sustainability through reduction of over-consumption can provide economic benefits. Economic implementation of sustainability principles can include: fostering and supporting sustainable industry; business and ecotourism; funding sustainability research and development; environmental education; and relevant to this study, the implementation of sustainable and passive design and construction techniques.
3.2.3. Sustainability assessment
One frequently utilised method of sustainability assessment is the implementation of indicators and establishment of clear goals. This can be undertaken at a local, state or federal level, and is popular because it focuses on the consideration of resource consumption, waste production and standard of living, and allows the production of visual representations of sustainability performance. Indicators can be tailored to suit the environmental, economic and social situation of specific locations (Newman, 1999).
Indicators can be broad ranging, examining waste, water, livability, amenity, health, air quality, energy, material consumption, land use, biodiversity and transport. Indicators relevant to this study would be:
reductions in per capita energy consumption;
reduction in per capita greenhouse gas emissions;
reduction in percentage of poor quality housing; and
reduction in per capita consumption of building materials (Newman, 1999).
3.2.4. Ecological footprint
Ecological Footprint (EF) has become a popular sustainability indicator since introduced by Wackernagel and Rees (1996). This technique estimates the area of land necessary to sustain the activities of a city or individual. This allows an estimate of the demands that humans place on nature, by comparing consumption and utilisation of natural resources with the earth‟s ability to renew these resources. EF calculation uses a method similar to life cycle analysis, where the land area required for the production of food and textiles, mineral extraction, construction of dwellings and other buildings, and the processing of waste is appraised. Also to be considered is the area of land required for the natural processing of carbon dioxide into biomass (Crocombe, 2007, Mobbs, 2001, Newman, 1999). Sustainability assessment allows the creation of a tangible unit for determining if a city, household or individual is over consuming and functioning unsustainably. Calculations of EF show that developed countries need to drastically reduce consumption, waste production, and energy expenditure (Newman, 1999).
3.2.5. Sustainable design as an aspect of sustainability
The design, creation, functioning and eventual demolition of residences, and the accompanying material use, energy consumption, and waste production, mean that the built environment presents a particularly complex challenge in terms of improving sustainability. Incorporating principles of sustainability into building design is important in reducing this consumption and the resultant impacts(Argue et al., 1978, Yudelson, 2007). Halliday (2008) identifies a range of criteria to which buildings should be subject to improve sustainability:
enhance biodiversity and not using materials sourced from threatened species or taken from sensitive or threatened environments, and where possible improve natural ecosystems and habitats through appropriate planning and resource consumption;
support communities by identifying and meeting the essential requirements and needs, and the desires of communities, including stakeholder involvement in key decision making processes;
use resources effectively by not unnecessarily consuming resources during materials sourcing, construction, building function, and demolition, and by reducing energy, water and materials waste due to inefficiency, short product lifespan, poor construction and manufacturing processes;
minimise pollution by reducing dependence on materials, products, energy, transport, and management practices that produce waste or other pollutants;
create healthy environments that improve the living standards of residents, reduce exposure to physical risk, toxic material, and harmful organisms; and
manage the process through appropriate delivery of sustainable projects in both the ongoing and short term.
Information underpinning the principles of sustainable design is readily available, yet criteria and standards are frequently not achieved in modern residential construction projects. Failure to apply even the most basic principles of sustainable design will result in dwellings that are more polluting and less energy and water efficient. (Halliday, 2008, Mobbs, 2001).
The efficient use of energy and the effective use of building materials are clearly noted in these criteria, and are highly important considerations in this research. They underpin the principles of passive design and the successful use of thermal mass to improve building thermal comfort.
Sustainable design, and its subset of passive design, are important aspects of the broader framework of sustainability, and can contribute to environmental, social and economic benefits. The environmental benefits of sustainable design include: reductions in the consumption of building materials, water, and energy; and a reduced ecological footprint. The social benefits of sustainable design include: improved living spaces and conditions; better health of building residents; and more amenable neighbourhoods (Argue et al., 1978, Reardon et al., 2005, Yudelson, 2007).
For the individual, the economic benefits of sustainable design stem largely from reductions in costs associated with resource consumption such as expenditure on energy, water and in some cases, building materials (Crocombe, 2007, Yudelson, 2007). There are, however, broader economic benefits provided by sustainable design, such as the opening of new markets for the production of new technologies and materials, and the mitigation of potential costs associated with the emission of pollutants such as greenhouse gases.
Sustainability is an important factor that underpins this research, and needs to be considered in the design of thermally comfortable buildings that are appropriate to climate. The uptake of even minor changes based on these principles will provide benefits, making the incorporation of sustainable principles into the design of residential buildings an important method of improving national and global sustainability by reducing carbon emissions, materials wastage, and resource consumption (Argue et al., 1978, Crocombe, 2007, Mobbs, 2001, Reardon et al., 2005, Yudelson, 2007).