WE could see more multi-year El Niño and La Niña events in Australia, says ANU researcher Dr Georgy Falster.

She said changes to the Pacific Walker Circulation – shifts in atmospheric patterns above the Pacific Ocean – have implications for El Niño and La Niña events in Australia and how they might change in the future.

These changes meant that in the future we could see El Niño and La Niña events that lasted for two to three years.

“After Australia saw severe flooding and rainfall from a rare three-year La Niña event, our research has found that one of the key drivers of these events is changing, with slightly slower transitions between La Niña and El Niño events,” she said.

Dr Falster started this research as a postdoctoral research associate at Washington University in St. Louis.

“The circulation of the atmosphere over the Pacific Ocean has changed. This means in the future we could see longer La Niña or El Niño events as the atmospheric flow above the Pacific Ocean switches more slowly between La Niña and El Niño phases,” she said.

“That could exacerbate the associated risks of drought, fire, rains and floods.

“It’s also more likely we’ll see a longer gap separating El Niño and La Niña, meaning dry El Niño years are less likely to be followed straight away by wet La Niña years.”