CSIRO and the Bureau of Meteorology’s latest State of the climate report48 concludes that, in the coming decades, Australia will be hotter and much of the continent will be drier. More specifically, the report summarises the main direct effects of climate change as follows:
- By 2030, projections show average temperatures rising by 0.6–1.5 °C, in addition to an existing rise of around 0.7 °C since 1960.
- By 2070, if growth in GHG emissions continues in line with past trends, projected warming will be in the range of 2.2–5.0 °C. Even at the lower end of this range, the projected increase is near or above the level regarded by many climate scientists as likely to trigger ‘dangerous climate change’. (See Schneider and Lane49 for a discussion of the complexities of the concept of dangerous climate change.)
- Compared with the last two decades of the 20th century, southern Australia is likely to experience reduced winter rain, and spring rainfall declines are expected in southern and eastern areas. In south-west Western Australia, reductions in autumn rainfall are likely to add to pressures associated with the existing decades-long decline in winter rain. Northern Australia is likely to experience an increase in annual and summer rainfall.50
In addition to directly affecting large-scale aspects of climate, such as average temperature and precipitation, human-induced climate change has the potential to alter the frequency and severity of extreme events, such as storms, floods, droughts and heatwaves.50–53 As noted above, separating the effect of climate change from that of natural processes can be difficult, and this uncertainty greatly complicates efforts to characterise likely changes in these extreme events. Nevertheless, improving our understanding of the vulnerabilities associated with such changes is an essential step in planning our adaptation to climate change.54