El Niño to return? Auckland floods linked to La Niña

After three years of experiencing the La Niña weather phenomenon, El Niño is expected to return in 2023, but not without bringing new dangers.

The recent, severe floods in Auckland, New Zealand were said to be exacerbated by La Niña, which causes the North Island to receive more rainfall than normal, due to the directional shift of prevalent winds. Different impacts are expected in different areas.

Both La Niña and El Niño are two sides of the El Niño Southern Oscillation (ENSO) which impacts water temperatures in the equatorial Pacific Ocean. La Niña brings cooler waters while El Niño brings warmer waters.

El Niño is known to intensify severe weather events across much of the planet and causes large swings year-to-year in weather differences.

In addition to influencing weather, both sides of the ENSO coin impact the global climate. La Niña helps cool temperatures. Despite this, 2022 still became one of the hottest years on record.

The potential arrival of El Niño means more heat records are likely to be breached in 2023, and since it intensifies later into the year, 2024 too.

Its impact varies in different regions. In western Pacific areas such as Australia conditions become drier, and hotter. A stark change after years of severe flooding due to intense rainfall.

In Europe the impact of El Niño arriving is not as severe although Spain and Portugal can often see wetter, and warmer winters. Particularly strong events also impact the UK and Ireland similarly.

There is currently a 66% of El Niño forming by August according to the US National Oceanic and Atmospheric Administration.

Not all El Niño events are the same in scale, it is still to early to predict how severe any potential event this year would be.