La Nina: Rare ‘triple-dip’ likely for first time this century, bringing greater global drought risk

The ongoing La Niña climate pattern is likely to continue for the third, consecutive winter - creating a rare “triple-dip” event, the United Nations’ World Meteorological Organization (WMO) announced on Wednesday.

It would mean only the third triple La Niña event since 1950, and the first this century.

La Niña is a shift in the Earth’s climate that occurs every few years, driven by cooler waters in the eastern-central Pacific. In contrast, warmer waters in that region create its counterpart, El Niño.

A longer La Niña could exacerbate disasters linked to the climate crisis like the ongoing severe droughts in the US southwest and East Africa, as well as increasing flood risk in Australia.

“It is exceptional to have three consecutive years with a La Niña event,” WMO Secretary-General Petteri Taalas said, in a statement.

The WMO gives the Pacific Ocean a 70 per cent chance of staying in the La Niña pattern between September and November 2022 and a 55 per cent chance between December and February 2023. The current La Niña began in September 2020.

These events upend weather patterns around the world. During a strong La Niña winter, the southern US, Peru and Ecuador will be much drier than usual, and on the other side of the Pacific, Australia, Indonesia and southeast Asia will be much wetter.

La Niña can also strengthen hurricane season in the Atlantic, part of the reason why there have been so many hurricanes in the past couple of years.

Another La Niña winter will mean that many communities who’ve dealt with this extreme weather over the past two years may not get a reprieve.

In the southwest US, another dry winter could further jeopardize low water supplies in California, Nevada and Arizona.

Additionally, further drought could increase wildfire risk next summer as the wilderness goes without much water for an additional year.

Drought could continue in east African countries like Kenya, Somalia and Ethiopia too, where millions of people are facing hunger as dry conditions have killed off crops and cattle.

“The new La Niña Update unfortunately confirms regional climate projections that the devastating drought in the Horn of Africa will worsen and affect millions of people,” Dr Taalas said.

In eastern Australia, another La Niña season could bring more flood risks in the Southern Hemisphere spring, which starts in September, Reuters reported.

In July, more than 20 people died and tens of thousands of people faced evacuation warnings as torrential flooding hit the country.

While a strong La Niña is no picnic, its counterpart isn’t necessarily pleasant either. During an El Niño pattern, many of these climate impacts are reversed – the southwest US, Peru and Ecuador will get much wetter while Australia, Indonesia and southeast Asia get much drier.

Some years don’t have particularly strong El Niño or La Niña effects. After a short El Niño event between autumn 2018 and summer 2019, Earth was in a neutral state for about a year.

La Niña years are cooler on average than El Niño as the extra cold water in the Pacific cools the whole planet, according to the US National Oceanic and Atmospheric Administration (NOAA).

But La Niña doesn’t slow down the human-driven climate crisis — it just causes a temporary dip in temperatures.

“Its cooling influence is temporarily slowing the rise in global temperatures – but it will not halt or reverse the long-term warming trend,” Dr Taalas said.

Exactly how the climate crisis will affect El Niño and La Niña is being researched by climate scientists. One NOAA scientist said in 2020 that planetary heating might increase the frequency of particularly strong El Niño and La Niña events.

The climate crisis is raising the risk of disasters like droughts and storms regardless of the El Niño/La Niña cycle. In the southwest US, climate crisis-powered “megadrought” has crippled water supplies in the region for more than 20 years.