Mechanisms Explaining Recent Changes in Australian Climate Extremes

In 2010–2012, Australia had its record highest 2 year rainfall, as well as repeated shorter‐term extreme rainfall events and damaging floods. Later in 2013, Australia experienced its record hottest year, together with repeated shorter‐term temperature records and heat waves in different regions. In this chapter, we discuss the mechanisms explaining the extreme rainfall affecting Australia in 2010–2012 and the extreme temperatures affecting Australia in 2013 from a climate perspective. We focus on contributing factors such as El Niño–Southern Oscillation and human‐caused climate change on the likelihood of such events. We find that the extreme 2010–2012 rainfall was primarily associated with the combination of the influence of two consecutive strong La Niña events and chaotic climate variability. Any influence of climate change is found to be weaker and harder to distinguish from natural climate variability. Conversely, human‐caused climate change was an important contributor to the extreme temperatures across Australia in 2013, and the record temperature in 2013 was virtually impossible to occur due to natural variability alone. In the future, natural variability and ENSO will continue to greatly affect temperature and rainfall extremes. In addition, climate change is expected to continue to increase the frequency and intensity of extreme high temperatures across Australia.