The La Niña has affected temperature and precipitation patterns and exacerbated drought and flooding in different parts of the world including the horn of Africa.
The phenomena “will continue until at least August and possibly to the northern hemisphere fall and start of winter,” said the World Meteorological Organization in a new update on Friday.
The update also says some long-lead predictions even suggest that it might persist into 2023. “If so, it would only be the third ‘triple-dip La Niña’ (three consecutive northern hemisphere winters of La Niña conditions) since 1950,” the update indicates.
La Niña refers to the large-scale cooling of the ocean surface temperatures in the central and eastern equatorial Pacific Ocean, coupled with changes in the tropical atmospheric circulation, namely winds, pressure, and rainfall.
It usually has the opposite impacts on weather and climate as El Niño, which is the warm phase of the so-called El Niño Southern Oscillation (ENSO).
The ongoing drought in the Horn of Africa and southern South America bear the hallmarks of La Niña, as does the above-average rainfall in South-East Asia and Australasia and predictions for an above-average Atlantic hurricane season.
However, all naturally occurring climate events now take place in the context of human-induced climate change, which is increasing global temperatures, exacerbating extreme weather and climate, and impacting seasonal rainfall and temperature patterns.
“Human-induced climate change amplifies the impacts of naturally occurring events like La Niña and is increasingly influencing our weather patterns, in particular through more intense heat and drought and the associated risk of wildfires – as well as record-breaking deluges of rainfall and flooding,” said WMO Secretary-General Prof. Petteri Taalas, in a statement.
Taalas said the WMO is providing tailored support to the humanitarian sector – as witnessed by a recent multi-agency alert on the worsening drought in East Africa.
“Improved seasonal forecasts are pivotal in this because they help plan ahead and gain substantial socio-economic benefits in climate-sensitive sectors like agriculture, food security, health, and disaster risk reduction, “ said Prof. Taalas.
The current La Niña event started in September 2020 and continued through mid-May 2022 across the tropical Pacific. There was a temporary weakening of the oceanic components of La Niña during January and February 2022, but it has strengthened since March 2022.
WMO Global Producing Centers for Long-Range Forecasts indicate that there is about a 70% chance of the current La Niña conditions extending into boreal summer 2022, and about 50-60% during July-September 2022.
