At the beginning of the new millennium, Australia's cities and their peri-urban and rural hinterlands were in the midst of a worsening drought. Having developed in the mid-1990s, the Millennium Drought finally broke in 2010, at least in south-eastern Australia. It was the most severe drought experienced in southern Australia since instrumental records began in the early twentieth century, thanks to a combination of natural variability and anthropogenic climate change. The urgency of water restrictions and supply augmentation that had characterised the drought years gave way to more pressing matters of the electoral cycle. As Australian cities continue to grow, it remains be seen as to whether plans to shape the urban form as a water catchment of its own materialise beyond model suburbs and local initiatives and what their implementation might mean for the water infrastructure and cultures of the past.

This chapter presents the anthropogenic global water cycle: the overuse of natural water resources has led to a water deficit that has been further exacerbated by global warming and increasing drought intensity induced by fossil fuel use, combined with large water use for fossil fuels, increased energy generation for water transfer and treatment, and consequently further water use and impact on depleting water resources. The chapter presents a new assessment of global water withdrawal and consumption and wastewater for the different stages of fossil fuel production and consumption, using the most updated information on water intensity and energy production. The chapter highlights the high magnitude of the impaired water intensity derived from water contamination on a global scale. The chapter explores the global emission of carbon dioxide, water vapor, and methane from fossil fuel operations, including natural gas flaring. The chapter evaluates the energy use for water transport, wastewater treatments, and desalination, emphasizing that future water quantity and quality deterioration would require additional treated water and thus additional energy sources that would further exacerbate the anthropogenic water cycle. Finally, the chapter discusses the options for a clean future and transition to renewable energy sources with much lower water intensity and environmental impacts.

Our society does not need energy per se. We use the various forms of energy to accomplish desired actions – commuting to work, keeping the interior of homes at comfortable temperatures, producing industrial goods, etc. The so-called “minimum energy” requirement for processes is actually a thermodynamic maximum, defined by exergy. The application of the exergy methodology determines the benchmark for the minimum energy resources that arerequired to perform the desired actions and tasks. The minimum energy benchmark is determined for several processes including: natural gas transportation, refrigeration, liquefaction, drying, water desalination, and petroleum refining. The energy requirements for the lighting, heating and air-conditioning of buildings are also calculated as well as the minimum energy for the transportation of goods and the commuting of persons in conventional and electric vehicles. Given their importance for the transition to renewable energy forms, the exergy method is applied to energy storage systems. Several examples in this chapter offer assistance and resources for the application of the exergy methodology to energy-consuming systems and processes.