Bureau of Meteorology announces changes to climate driver updates

After last year’s wetter-than-usual El Nino summer, the weather bureau will tone down the emphasis on individual climate drivers.

The bureau will focus less on individual climate drivers like the Indian Ocean Dipole.

The nation’s weather bureau will stop publishing incremental updates on the likelihood of El Nino and La Nina hitting Australia, conceding the controversial indicators have sowed confusion and given Australians a false impression of the seasonal forecast.

The Bureau of Meteorology’s decision to ditch fortnightly climate driver updates, as well as the well-studied El Nino-Southern Oscillation dial, comes after complaints from farmers in late 2023 about the accuracy of the bureau’s forecasts, and public confusion over the status of climate indicators.

Instead, the national forecaster has encouraged its website users to look at its dynamic long-range 90-day forecasts of rainfall and temperature, which account for more variables.

Encouraged by the bureau, Australians have long kept an eye on La Nina and El Nino patterns that have traditionally heralded above-average rainfall or a hot, dry summer.

But the bureau said changes to the climate had affected the efficacy of the ENSO drivers to deliver an accurate indication of the weather.

Instead of the familiar dial showing neutral, watch, alert and El Nino or La Nina, the website now more definitively states El Nino, neutral or La Nina.

It is currently in “neutral” but under the old scale would be on “La Nina watch”.

The trimmed-down declaration will no longer be included on a climate driver page and will instead be found on Southern Hemisphere Monitoring web page.

Gone too is the aggregation of international climate model summaries and forecasts for ENSO and the Indian Ocean Dipole.

The bureau’s climate manager, Karl Braganza, said the changing climate had made current weather patterns more varied than historical trends, making old methods of forecasting less reliable than new models.

“We are moving away from focusing on individual environmental phenomena,” Dr Braganza said.

“In a changing climate it is more difficult to make predictions based on events when they are looked at individually – climate systems are complex and cannot be explained by just one influencing factor.”

Criticism of the bureau was widespread last year when some farmers blamed its El Nino declaration for spooking producers into selling livestock, leading to a flooded market that sent sheep and cattle prices tumbling.

Dr Braganza said the confusion generated by the bureau’s 2023 El Nino declaration, which came during heightened focus on the bushfire season ahead, had contributed to the decision to scale back the prominence of the ENSO.

Karl Braganza.

“If I did have my time over, I would try to differentiate the risk for the forecast of bushfires and the forecast for the risk of drought,” Dr Braganza told The Weekend Australian.

“I would deliver slightly different messaging for different sectors based on how they assess their risk.

“We realised there was mixed messaging from that.”

Dr Braganza said farmers in particular had focused on climate drivers to better understand the season ahead.

But without also consulting the more nuanced dynamic forecast model, it had led to confusion about the outlook.

As for the axing of the incremental ENSO dial and “watch and alert” system, Dr Braganza said it had led to confusion and overemphasis on indicators.

University of Melbourne weather researcher Kimberley Reid said weather models provided a better forecast because they relied on physics instead of historical precedents.

“Nowadays we have models that don’t need statistical relationships because they can replicate the underlying physics,” Dr Reid said.

“They can solve equations in the fundamental physics to inform the future.

“An index (like El Nino) in any field is useful but it can’t tell you everything.”

Dr Reid said the casual knowledge of climate drivers such as El Nino and La Nina among the Australian public was unique compared to other countries.

“But that can be bad as well, as we saw last year when people became too reliant on El Nino or La Nina, and they associated it too much with dry weather,” she said.

“That whole incident, I think, was a catalyst for the bureau’s overhaul.”