A new study suggests some El Niño events could be accurately predicted up to 12 months ahead, buying valuable time for farmers, emergency services and disaster-prone communities. The findings from researchers at the University of Melbourne and CSIRO come as a remarkably strong El Niño has already contributed to sudden floods in eastern Africa, blistering heatwaves in Europe and intense hurricanes in the eastern Pacific.
Climate and weather forecasting largely relies on physics-based models that simulate the Earth's atmosphere and oceans. Forecasters supply these models with present conditions such as ocean temperatures, currents, winds and humidity from a global network of satellites, weather stations, ocean buoys and moorings. El Niños and La Niñas are largely shaped by the ocean, which moves more slowly, allowing predictions over a longer period. Events typically peak around December and can be accurately predicted about six months ahead.
However, forecasts made between March and May are notoriously unreliable because this time of year is susceptible to the butterfly effect, with even small fluctuations preventing accurate predictions. The researchers examined whether it is possible to overcome this uncertainty.
Using a dataset of 7,500 forecasts generated by nine models developed in different countries, the researchers checked whether early predictions came true and searched for patterns in early forecast performance. They sorted forecasts based on what was happening in the Pacific when they were first initiated: La Niña, El Niño or neutral conditions.
A clear pattern emerged across all nine models: forecasts that began during a La Niña were most successful in predicting what would happen a year later. By contrast, forecasts initiated in neutral conditions were very likely to be wrong. The researchers suggest La Niña conditions have a stabilising influence, making predictions more reliable.
During La Niña years, there is an opportunity to make early forecasts and issue early warnings so communities, emergency responders and governments can prepare for future El Niños. Australia's Bureau of Meteorology warned of the current El Niño in June, which is the earliest point at which reliable predictions can currently be made.
The researchers said more work is needed to translate these findings into practice, focusing on why La Niña events support better model performance and whether particular ocean or atmosphere patterns can indicate when a model is making correct predictions.
Analysis
Why This Matters
- Earlier warnings could give farmers, disaster planners and emergency services more time to prepare for floods, heatwaves and hurricanes linked to El Niño
- The ability to know when forecasts are reliable (during La Niña periods) versus unreliable (neutral conditions) could help communities avoid costly false alarms or missed warnings
- As climate change may intensify extreme El Niños, longer lead times for predictions become increasingly important for global disaster preparedness
Background
El Niño is a natural climate pattern driven by warming of the Pacific Ocean that affects temperature, rainfall and winds across the globe. Its opposite, La Niña, involves cooler ocean temperatures. These cycles are among the most predictable climate phenomena, but forecasts have a well-known reliability gap during the March-May period. The current El Niño, which forecasters warned about in June, is described as remarkably strong.
Key Perspectives
Mandy Freund (University of Melbourne) and Nandini Ramesh (CSIRO): Their study of 7,500 forecasts from nine models found La Niña conditions have a stabilising influence, making year-ahead predictions more likely to be reliable, while neutral conditions made them very likely to be wrong.
What to Watch
- Whether forecast agencies such as Australia's Bureau of Meteorology begin issuing experimental long-range El Niño outlooks during La Niña periods
- Further research into why La Niña conditions stabilise forecasts and whether specific ocean or atmosphere patterns can confirm when a model is making correct predictions
- The performance of the current El Niño against predictions made from June, as a test of the six-month forecast window
Checked
12 claims in this story checked against 1 source: 11 supported.
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- SupportedSome El Niño events may be accurately predicted up to 12 months ahead.The Conversation – Articles (AU): “Our new study suggests it may be possible to accurately predict some El Niños up to 12 months ahead of time”
- Not in the sourcesThe story identifies the researchers as being at the University of Melbourne and CSIRO.The Conversation – Articles (AU): “Nandini Ramesh receives funding from the CSIRO. She has previously received funding from the Australian Research Council and the US National Aeronautics and Space Administration and Department of Energy. She is affiliated with the University of New South Wales. Mandy Freund receives funding from The University of Melbourne”
- SupportedThe ongoing El Niño has contributed to floods in eastern Africa, heatwaves in Europe and hurricanes in the eastern Pacific.The Conversation – Articles (AU): “The ongoing El Niño has already contributed to sudden floods in eastern Africa, blistering heatwaves in Europe and intense hurricanes in the eastern Pacific.”
- SupportedThe summary says forecasts initiated during La Niña are most reliable and could give communities more time to prepare.The Conversation – Articles (AU): “forecasts that began during a La Niña were most successful in predicting what would happen a year later.”
- SupportedThe Bureau of Meteorology warned of the current El Niño in June, the earliest point at which reliable predictions can currently be made.The Conversation – Articles (AU): “Australia’s Bureau of Meteorology warned us of this El Niño in June, which is currently the earliest point at which reliable predictions can be made.”
- SupportedForecasts use physics-based models supplied with current conditions, including ocean temperatures, currents, winds and humidity, from a global network of instruments.The Conversation – Articles (AU): “forecasters supply these models with information about present conditions, including ocean temperatures, currents, winds and humidity. This data comes from a vast global network of satellites, weather stations, ocean buoys and moorings.”
- SupportedEl Niño and La Niña events typically peak around December and can be accurately predicted about six months ahead.The Conversation – Articles (AU): “These events typically peak around December and can be accurately predicted about six months ahead.”
- SupportedForecasts made between March and May are notoriously unreliable because small fluctuations can prevent accurate predictions.The Conversation – Articles (AU): “Forecasts made between March and May are notoriously unreliable. Because of the conditions in the atmosphere and ocean at this time of year, it becomes susceptible to the butterfly effect, with even small fluctuations preventing models from making accurate predictions.”
- SupportedThe researchers analysed 7,500 forecasts generated by nine models developed in different countries.The Conversation – Articles (AU): “we used a massive dataset of 7,500 forecasts generated by nine models, developed in different countries.”
- SupportedForecasts initiated during La Niña were most successful at predicting conditions a year later; those initiated in neutral conditions were very likely to be wrong, and the finding held across all nine models.The Conversation – Articles (AU): “forecasts that began during a La Niña were most successful in predicting what would happen a year later. By contrast, forecasts initiated in neutral conditions were very likely to be wrong. These findings were consistent across all nine models we studied.”
- SupportedThe researchers suggest La Niña conditions have a stabilising influence that makes predictions more reliable.The Conversation – Articles (AU): “This suggests La Niña conditions have a stabilising influence, meaning predictions are more likely to be reliable.”
- SupportedThe researchers say more work is needed to understand why La Niña improves model performance and whether patterns can indicate correct predictions.The Conversation – Articles (AU): “Studies should focus on why La Niña events support better model performance and if there are particular ocean or atmosphere patterns that can tell us when a model is making correct predictions.”
