- Much of Australia is drought-prone, and the risk is expected to increase as global warming continues.
- That’s why it’s important for Australia to be prepared for droughts, particularly those lasting multiple years.
- If we add in human-caused climate change, it suggests future droughts will be far worse than we imagined.
Rainfall records aren’t enough
- But in Australia these records only go back to around the year 1900.
- This doesn’t fully record the huge range of natural rainfall variability over many hundreds of years.
- To a degree, we can get these long records from features of the environment such as trees, which record information about rainfall changes in their annual growth rings.
- First, we looked at the characteristics of Australian droughts due to natural fluctuations in rainfall.
Our results
- This change is consistent with the rainfall trends expected in these regions in future due to human-caused climate change.
- It suggests that an emerging human influence on our climate has already made southern parts of Australia more drought-prone.
- In other words, human-caused climate change had probably not yet caused Australian droughts to be any drier, or changed how often we are in drought.
How bad could Australian droughts be?
- That is far longer than any drought that has been experienced in Australia since instrumental records began.
- This includes the Murray-Darling Basin where typical droughts last century lasted four to five years.
Mega-droughts are possible in Australia
- This new research shows mega-droughts in Australia are possible – even without the influence of climate change.
- This finding is supported by evidence drawn from ice cores, which suggests a 39-year drought gripped eastern Australia around 800 years ago.
- This is concerning, because climate change is also increasing the chance of reduced rainfall across much of southern Australia.
Georgina Falster receives funding from the Australian Research Council, through the Centre of Excellence for Climate Extremes. Nerilie Abram receives funding from the Australian Research Council through the Centre of Excellence for Climate Extremes, the Centre of Excellence for 21st Century Weather, the Australian Centre for Excellence in Antarctic Science, and a Discovery Project Nicky Wright receives funding from the Australian Research Council and industry sources.