Global change can be defined strictly in terms of changes in atmospheric composition, climate and land use (Walker and Steffen 1996), although broader definitions also include human population, economy and urbanisation (Steffen et al. 2004). In Australia, global change significantly affects the drivers of fire activity and there is potential for considerable changes in fire regimes. It is widely accepted that carbon dioxide (C02) concentration in the atmosphere is steadily increasing (see Steele et al. 2007), as is nitrous oxide (Forster et al. 2007). Atmospheric methane concentration has also risen significantly, but is now relatively constant (Beer et al. 2006). Given the increase in these greenhouse gases, an increase in the energy trapped by the atmosphere is expected, resulting in atmospheric warming (Arrhenius 1896; IPCC 2007). Therefore, Australia's climate is changing. Average temperatures are expected to increase by between 0.6 and 4°C, depending on emission scenario, timeframe and locality (CSIRO and Australian Bureau of Meteorology 2007) (Figure 7.1). Patterns of precipitation are projected to shift by the end of this century, with higher precipitation in the continent's north and east and declines in the south and west - a pattern generally mimicked by evaporation (Lim and Roderick 2009) (Figure 7.2). Average relative humidity could decline by up to 4% in central and eastern Australia by 2070, while average wind speed may increase by 10% in similar areas (see CSIRO and Australian Bureau of Meteorology 2007). The frequency of extreme frontal events may double or more by the end of this century (Hasson et al. 2009), yet outcomes for circulation patterns associated with El Nifio and the Southern Oscillation (ENSO) (Philander 1990) are uncertain (Collins et al. 2010). Importantly, uncertainty arising from choice of emission scenarios and climate sensitivity, and from differences among models, is common (CSIRO and Australian Bureau of Meteorology 2007; Lim and Roderick 2009).