ich are widely distributed, sold, used, discarded, disposed and replaced. Walker (2006) notes that ‘this system’s flow of resources and energy is linear and unidirectional: most of it is not recyclable, ending up in landfill’ . Repair, re-use, refurbishment and retrieval (recovery) of resources, materials and building components do not yet feature in this system; construction systems that allow 100 percent recyclability, or disassembly and re-use of entire components, would be far better.
Architects and planners are now looking for new, responsible ways of living in cities and better inner-city housing models, to attract people back from suburbs to the centres. It is clear that things are changing and we must make every effort to future-proof the built environment by designing more resilient urban systems and more compact urban housing. The technology for energy generation and supply is transforming quickly, while the construction sector is still working out the ramifications of climate change and possible responses. However, the transition from fossil fuels to renewable sources of energy is moving much faster than most people realize, notes environmentalist Lester Brown (2009) ; while a mostly conservative and therefore slow-to-change construction sector has yet to fully embrace principles of ethical consumption, low carbon construction and waste reduction.
Housing construction is of exceptional significance as a driver of the Australian economy and a fundamental social need. A report by FWPA (2012)  states that ‘the areas of design, material technology and construction process management in housing, have significant potential for improvement through emerging technologies, but to date, the Australian construction industry has been slow to adopt new technologies relative to other advanced countries’.
1.1. Better Inner-City Housing Models for Urban Infill
Australian and North American cities in particular will need to be transformed towards higher densities and a more compact urban form using infill to reduce their car dependency, high greenhouse gas emissions and land consumption [1,3]. Unsustainable ‘functional city’ models evolved during the automobile era, in a time of cheap fossil fuels. Today, the ratio of parks to parking lots has become a solid indicator of the liveability of a city—an indication of whether the city is designed for people or for cars. While cars promise mobility (and in a largely rural setting they can provide it), there is now an inherent conflict between automobiles and the liveability of a city . Increasing travel costs (due to rising oil prices) will have the most effect on people living in outer suburbs, especially the elderly who often live isolated in suburban areas without efficient public transport. Worldwide, planners are reconsidering the urban role of automobiles and redesigning inner-city communities so that public transportation is the centrepiece of mobility and streets are more pedestrian and bicycle friendly. Good examples of such green districts with compact urban form and mix of housing types, developed as urban infill on brownfield sites, are Vauban-Freiburg (Germany), Hammarby-Stockholm (Sweden) and Malmo Waterfront (Sweden), and the urban revitalization of Berlin and Barcelona.
In Australia we urgently need better, more liveable and affordable models of inner-city housing as urban infill on brownfield sites [13,14]. If this were combined with low-carbon prefabricated construction systems, developers could deliver infill developments more rapidly and affordable, without unpleasant noise for neighbours. The lack of storage space for construction components and materials on inner-city sites would not matter, as prefabricated elements would be produced off-site and delivered to sites just in time for assembly.
The other emerging topic is behaviour change. Our values and behaviours define the way we aspire to live. Changing behaviour in regard to inner-city living and consumption patterns is likely to deliver significant improvements, helping to curb the threat of environmental de