By Dr Joe Milton, the Australian Science Media Centre

The decision follows the declaration of El Niño by the US National Oceanic and Atmospheric Administration in June and the World Meteorological Organization (WMO) in July.

El Niño is a climate pattern that plays a major role in Australia’s weather and climate. Its non-identical twin climate pattern, La Niña, has held sway over the country for the last three years, leading to cooler, wetter conditions than usual.

But El Niño generally leads to hotter and drier conditions for much of Australia, increasing the chances of heatwaves and drought, according to Dr Andrew King from the University of Melbourne and the ARC Centre of Excellence for Climate Extremes.

With the arrival of El Niño, the surface of the seas in the central and eastern Pacific Ocean warm up, while the seas north of Australia cool down.

“The unusually hot weather we’re seeing across southeast Australia at the moment is a warning of the kind of extremes we’re likely to see more of over the next few months,” Dr King told the AusSMC.

Dr Zoe Gillett is a Research Fellow at the ARC Centre of Excellence for Climate Extremes

Dr Zoe Gillett from the ARC Centre of Excellence for Climate Extremes and UNSW told the Centre another climate driver is in play this year as well as El Niño, and is likely to boost its warming and drying effects.

“A positive Indian Ocean Dipole event, the El Niño of the Indian Ocean, has also been declared,” she said.

“When El Niño and the positive Indian Ocean Dipole co-occur, drying in Australia is typically amplified.”

Dr Linden Ashcroft from The University of Melbourne told the AusSMC Australia needs to “prepare for a hot and dry end to 2023”.

However, CSIRO’s Dr Nandini Ramesh said the years of La Niña may help counteract some of the heating and drying effects of El Niño.

“Three rainy La Niña years have provided us with a buffer against drought, with soil moisture and reservoir levels still high,” he said. “This buffer means that we are not necessarily guaranteed a catastrophic fire season this year.”

But Dr Milton Speer from the University of Technology Sydney said the years of La Niña have been masking the longer-term warming trend as climate change accelerates.

“Significant, insidious drying and warming… has been occurring from about the mid-1990s,” he said.

It was a concern shared by Dr Hamish Clarke from the University of Melbourne.

“Any additional warming we see as a result of El Nino this summer will come on top of decades of human-caused climate change that has already significantly raised temperatures and bushfire risk in many areas,” he said. “Without much stronger climate action than we are currently taking, we can expect to see much worse conditions in the future.”

And Delene Webber from UniSA said all Australians should make sure they’re bushfire-ready now.

“We can’t impact this climate pattern…but we can take time now, before the busy summer season, and prepare our homes and properties. We can take time to make sure our Bushfire Survival Plans are up to date.”

You can read the EXPERT REACTION in full here.

This article originally appeared in Science Deadline, a weekly newsletter from the AusSMC. You are free to republish this story, in full, with appropriate credit.

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