September 19, 2023
The Bureau of Meteorology has finally declared what many farmers already knew … an El Niño event is under way.
El Niño – and its opposite La Niña – reflect changes in the tropical Pacific Ocean which affect global weather patterns.
El Niño events are usually associated with low rainfall or drought, particularly in eastern Australia, while La Niña can bring heavier rainfall and flooding.
BOM declared an El Niño Watch in March (50 per cent chance of it occurring this year) and an El Niño Alert (70 per cent chance) in June.
A BOM spokesperson said on Tuesday the El Niño-Southern Oscillation (ENSO) outlook now met three of the four criteria necessary to officially declare an El Niño event.
And climate models suggest this El Niño is likely to continue until at least the end of summer.
Dr Zoe Gillett, a climate scientist from the ARC Centre of Excellence for Climate Extremes at UNSW, said a positive Indian Ocean Dipole event had also been declared.
“El Niño typically reduces the chance of spring rain in eastern Australia and increases the chance of warm days,” Dr Gillett said.
“A positive Indian Ocean Dipole tends to reduce the chance of spring rain in central and south-eastern Australia.
“The Bureau of Meteorology’s outlook indicates warmer and drier conditions for most of Australia in the upcoming three months.
“When El Niño and the positive Indian Ocean Dipole co-occur, drying in Australia is typically amplified.
“The last time El Niño and the positive Indian Ocean Dipole occurred together was in 2015.”
Dr Linden Ashcroft, a lecturer in Climate Science at the University of Melbourne, said conditions had been brewing in the Pacific and Indian oceans for a few months.
“Eastern Australia is already experiencing some of the impacts that an El Niño and positive Indian Ocean Dipole event can bring,” Dr Ashcroft said.
“These climate drivers, on top of background warming due to climate change, means we need to prepare for a hot and dry end to 2023.”
