Key Points
- El Niño events typically deliver drier conditions for much of the country, but particularly eastern Australia.
- The declaration coincides with severe weather warnings for swathes of Australia's south east.
- Extreme heat is spreading fire danger zones across the east coast.
As parts of Australia swelter through searing September heat and dangerous fire conditions, the weather bureau has declared a double whammy that raises the risk of more of the same.
The Bureau of Meteorology (BoM) has formally declared both in the Pacific Ocean, to Australia's east, and a positive , to the country's west.
It is the first time the two weather events have occurred together in eight years.
El Niño and a positive Indian Ocean Dipole: What will they mean?
El Niño events typically deliver drier conditions for much of the country, particularly eastern Australia, as well as above-average temperatures.
A positive IOD often results in less rainfall than average over parts of Australia.
When the two patterns coincide it can magnify the drying effects.
Parts of Australia are sweltering through searing September heat and dangerous fire conditions, and BoM's declaration on Tuesday raises the risk of more of the same. Source: Supplied / Evan Collis
Braganza said Victoria, in particular, tended to dry out under a positive IOD influence in spring.
"That tends to really have an influence on Victoria's rainfall,'' he said.
"Coupled with El Niño, we'd expect to see conditions, probably out to mid-summer for Victoria, looking warm and dry.
"NSW similarly ... has a large influence with a positive IOD over the spring. We're already seeing that extended period of warmth since the start of the month in those two states."
Will they increase the risk of bushfires?
Braganza said the conditions the events typically deliver are "accompanied by an increase in fire danger and extreme heat risk".
"It's really up to individuals and communities now to prepare for a summer of heat and fire hazards."
He said conditions were not as bad as they were leading into the catastrophic fires of Australia's Black Summer, but he also warned things were rapidly drying out after three consecutive years of wet conditions.
"Leading into Black Summer in 2019 ... we had years of preceding drought,'' he said.
"We do have a wetter landscape out there, (but) it is drying out more rapidly than has occurred in recent years.
"We are already seeing extreme conditions in some parts of the continent, particularly in the duration of heat, so we've had an extended period of warm and dry weather to start spring.
"Today, we've had catastrophic fire conditions on the south coast of NSW, just to underscore that risk."
How long will the El Niño last?
Likely until the end of summer, Braganza said.
Professor Delene Weber, an environmental scientist and bushfire researcher at the University of South Australia, said because much of the continent likely faces a "warmer, driver summer" it was important to update and rehearse bushfire survival plans.
"It may sound over-zealous, but assigning a day and rehearsing your bushfire plan, could help you identify areas for improvement and importantly, that rehearsal could be invaluable if you were to experience a fire," Delene said in comments distributed by the Australian Science Media Centre.
"Lastly, talk to your neighbours. It takes a community to make an area bushfire safer. Consider offering to help people with mowing, pruning or clearing gutters."
Victoria's Country Fire Authority encourages not only people who live in the country to have a bushfire survival plan, but also those who live near areas with significant bush, forest, long grass, or coastal scrub.
'Extreme' fire danger warnings could double in some areas
Fire danger zones are spreading across the east coast as extreme heat closes schools and threatens Australians young and old, with the nation "at the precipice".
A spring heatwave has large parts of NSW and eastern Victoria sweltering under maximum temperatures 10 to 15 degrees Celsius above the September average.
Extreme heat is forecast to drive north into Queensland, bringing fire danger to southern parts of the state and into the vast outback Channel Country on Thursday and Friday.
Authorities have declared an extreme fire danger for the Greater Hunter and Greater Sydney regions on Wednesday, with temperatures in the mid-30s and gusty winds expected.
An image of the firestorm that came close to claiming the lives of nine people in NSW's Kangaroo Valley on 4 January 2020. Source: AAP / ADRIAN TURNER/PR IMAGE
The unseasonably hot and dry conditions are being felt across southern Australia, with temperatures peaking at 8-16 degrees Celsius above average across much of South Australia, NSW and Victoria.
Extreme heat one of the most direct effects of climate change
Extreme heat is one of the most direct and measurable shocks from climate change and one of the deadliest, according to the independent Climate Council.
A report released by the council on Wednesday found existing government targets leave Australia "barrelling towards catastrophe".
Already, more Australians have died as a result of extreme heat than any other natural hazard, they said.
"Right now, we stand at the precipice. Once we cross those tipping points, we cannot return," co-author Lesley Hughes said.
Australia 'on track" for even more harmful effects of global 'warming
Meanwhile, emissions from transport and heavy industry continue to rise, putting Australia on track for even more harmful levels of global warming, the Climate Council modelling shows.
Up to 250,000 Australian properties are at risk of coastal inundation under a rise of well over 2 degrees Celsius by the end of the century.
Marine ecosystems would collapse and irreversible change in rainfall patterns globally would destroy food production.
"So it really doesn't get much more urgent than this - we've got to aim higher and go faster," Prof Hughes said.
Under 3 degrees Celsius of global warming, there would be deadlier heatwaves and worsening fire conditions, according to the report, Mission Zero: How today's climate choices will reshape Australia.
The number of extreme fire days would double and in Queensland, heatwaves would occur as often as seven times a year and last on average 16 days.
Capital cities would experience a spike in extremely hot days, with Darwin forecast to have 265 days a year above 35 degrees Celsius.
But much deeper emissions cuts than planned for this decade could give the Great Barrier Reef a fighting chance, keep farmers on the land, and lower the risk of deadly floods, fires and droughts.
"It's game on, not game over, for climate action," Climate Council research director Simon Bradshaw said.
The report reiterates that Australia should cut emissions by three-quarters by 2030 and reach net zero emissions by 2035, not 2050.
