More severe rain events and longer droughts - that’s the prediction from new climate change modelling conducted by leading climate researchers in Australia.
To explain his research, Professor Steve Sherwood, of the University of NSW, likes to use the analogy of a bucket full of water.
“The atmosphere is always picking up moisture from evaporation. Eventually it becomes too much and it rains,’’ he says.
“With climate change basically that bucket gets bigger, so when the atmosphere hits a tipping point, the downpour is a lot bigger.’’
He says his climate models suggest that with a warming climate Australia faces either more aridity - longer droughts - or fewer but bigger and more severe rain events. This may mean there are longer periods with little rain or inconsistent rain which may affect cropping regimes. Also, moisture retention in soils will be under pressure from the increased temperatures.
‘’That’s not so good for running a farm,’’ Prof Sherwood says. His research with three other colleagues was published in Nature Climate Change, through the ARC Centre of Excellence for Climate System Science.
The researchers used advanced mathematics and unique climate models to come up with its findings.
Prof Sherwood’s modelling shows no part of Australia will be spared from climate change, but microclimates may help some areas dodge the most severe of the changes.
The weather, he says, may appear normal for two of three years, but then there could be sudden changes, with severe rainfall events.
“On the other side, aridity may increase and longer droughts are a possibility.’’
The research shows climate change will occur across the continent from the tropical north to the mid-latitudes.
The research found a two degree rise in average global temperatures could lead to a 10-30 per cent increase in extreme rain events, while a four percent rise in temperatures could create a 22-60 per cent increase in these events.
John Ellicott
journalist and author
journalist and author
