This was published 4 months ago
Australia set for a new normal with a mild winter, uncertain snowfall
If there is a new normal in the era of climate change, then the next few months could be it.
The Bureau of Meteorology has declared this year’s El Nino over, and the El Nino-Southern Oscillation is now in neutral phase. Other climate drivers, such as the Indian Ocean Dipole and the Southern Annular Mode, are also neutral.
Deciduous trees throughout NSW and Victoria are turning autumn colours.Credit: Wolter Peeters
The bureau’s climate manager Dr Karl Braganza said Australia was expecting “typical conditions” for the season - which also meant “a typical chance of extremes”.
He said the benchmark for what is typical has changed, so it was likely to be warmer than the 1961–1990 median.
“Australia has warmed by about one and a half degrees since 1910, and we’re in a non-stationary climate system, so it’s continuing to warm,” Braganza said.
Last year was the hottest year on record in both Australia and around the world, and this trend continued into early 2024.
Matthew England, a climate scientist at the University of NSW, said it probably would be a mild winter because of global warming. This meant average temperatures would be about 1.5 degrees higher than winters a few decades ago, but cold snaps could still occur.
“A lot of people think ‘Great, we’ve lost some of the front of winter’, but tourist organisations like the ski and snow sports sector are really worried about where that industry is going with progressively more mild winters as we go into the future.”
“To have warmer winters means snow conditions don’t benefit from that because if you do get snowfall overnight, it can melt in the daytime, and leaves the snow not powdery and soft but more like ice.”
Over the next three months, Braganza said rainfall patterns should be typical for the season, based on 1981–2018 averages. The bureau is expecting a dry May, with more rain or snow coming in June and July.
The El Nino-Southern Oscillation – the climatic pattern that shifts between the hotter, drier weather of El Nino and the cooler, wetter conditions of La Nina – has been in the El Nino phase since last September, but the bureau declared it over earlier this week.
Braganza said it was normal for the El Nino or La Nina system to revert to neutral at this time of year. In July, the climate system reactivates and forms either another El Nino, a La Nina or remains neutral.
Last year’s El Nino was preceded by three consecutive La Ninas, which also happened in 1954–1957, 1973–1976, and 1998 –2001.
Braganza said neutral years were most common over the past century, and it was too early to say if that was changing.
Three out of seven international climate models are predicting a La Nina after July, but the bureau has cautioned that El Nino and La Nina predictions made in mid-autumn tend to be less accurate than those made at other times of year.
The recent El Nino coincided with a marine heatwave that caused a wet, humid summer on the east coast. England said the heatwave was persisting, and while swimmers and surfers would benefit from the warmer ocean temperatures, it was bad news for nature.
The Australian Marine Conservation Society says such heatwaves slow the growth of some fish, activate deadly viruses in infected oysters, stress immobile creatures like shellfish, oysters and abalone, cause kelp forests and seagrass meadows to collapse and release stored carbon dioxide back into the atmosphere, and cause coral bleaching.
New data this week showed the extent of the fifth mass bleaching of the Great Barrier Reef since 2016.
On land, the outlook is good for most farmers, and consumers should see stable prices at the supermarket unless oil prices spike because of conflict in the Middle East.
Associate Professor Flavio Macau at Edith Cowan University said he expected food and vegetable production to be good or excellent this winter. Even if a La Nina occurred later in the year, he said it would have to be severe to compromise food production, and that was unlikely.
CSIRO agriculture scientist Lindsay Bell said climate change was making it more important for grain and livestock farmers to invest in new technology such as sensors to measure soil moisture.
“Farmers have been trying to manage climate variability for a long time … but it’s becoming more challenging because we have less confidence in how the seasons will play out,” Bell said.
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