Chances of a La Niña event emerging later this year are rising, here's what happened the last time we experienced this side of the El Niño Southern Oscillation.

From 2020 to 2023, the planet saw three consecutive years of the La Niña phenomenon, heralding cooler waters in the equatorial Pacific.

No two events are the same, though typically bring more rain to Australia, an increase in Atlantic hurricanes for the US, and a mixture of effects in Africa.

Over the three-year period between 2020 and 2023, Australia certainly saw more rainfall.

As many as eight separate severe flooding events took place over the period resulting in billions of dollars in damages and multiple deaths.

In 2022, the Wilson River passing through the city of Lismore, New South Wales reached a historic height of 14.4 metres.

Looking towards the U.S. we saw the impact evidenced in the hurricanes formed. As La Niña took hold during the 2020 hurricane season a total of 31 tropical cyclones, 14 hurricanes, and seven major hurricanes formed. It became the most active season on record.

The was followed by the third most active season on record in 2021. While 2022’s season saw fewer events, total damages passing $120 billion were the highest of the period.

Meanwhile, in Africa, La Niña has different effects. In the west, weather becomes wetter with floods more likely. In the east, drought is exacerbated, as we saw in the Horn of Africa which remained in the grip of the most severe drought for over 70 years.

Learn more about the El Niño Southern Oscillation with our video explainer!