The potential return of El Niño in 2023 poses the threat of record heat
The lake in La Sabana Park in San José, capital of Costa Rica, was affected by droughts caused by the El Niño phenomenon in 2018-2019. (File photo)
Several models predict the return of El Niño in 2023, a year that should be marked by temperature anomalies and significant heat events. However, climate change is disrupting this natural phenomenon and has its share of the unknown. Explanations.
Earlier this month, the European Copernicus program indicated in its annual report that 2022 had been the fifth hottest year in the world. Several countries in Europe have experienced record heat waves in the summer, despite the fact that we are going through an episode of the La Niña weather phenomenon, which tends to have a cooling effect on the globe.
< p class="e-p">However, La Niña, which has lasted since September 2020 – a particularly long episode – is expected to end this year to give way to El Niño, the warmer phase of the cycle. Different climate forecast models indicate that La Niña is expected to continue through March.
Although they subsequently predict the arrival of El Niño, these models disagree on when the alternation will occur. The phenomenon could manifest itself as early as 2023.
El Niño and La Niña are large-scale marine currents in the equatorial Pacific that influence, among other things, sea surface temperature, precipitation and wind patterns. They usually develop in the period from April to June, before reaching their maximum potency between October and February.
Last December, the Agency American Oceanic and Atmospheric Observatory (NOAA) estimated the odds of an El Niño from August to October 2023 at 66%. On January 19, the Colombia Climate School's International Research Institute for Climate and Society rated its likelihood down to 53-57% for the same period.
Climate experts like Bill McGuire, Emeritus Professor of Geophysical and Climate Hazards at University College London, are concerned about the scale of events that the next El Niño could bring. The extreme weather that plagued our planet in 2021 and 2022 will seem insignificant to us, he wrote in Wired magazine.
The El Niño phenomenon is usually associated with drought, heavy rains and floods. Nevertheless, the next episode of this phenomenon could prove to be more unpredictable than the previous ones.
If the last El Niño, in 2018-2019, was little felt in Canada , which ran from March 2015 to May 2016 – one of the strongest episodes on record – sent temperatures soaring across much of the country in winter and spring, according to Environment Canada .
It further led to drought anomalies in Africa, Central America, and Indonesia, while significant flooding occurred in northern Peru.
The answer is not the same if El Niño occurs in winter or in summer, specifies Philippe Gachon , professor in the Department of Geography at UQAM and researcher at the Center for the Study and Simulation of Climate on a Regional Scale.
If winter does occur, North America experiences higher temperatures than usual, while the south of the continent is cooler. Usually, the effects are less present in the rest of the globe, according to the expert.
But the scenario is quite different if El Niño occurs during the summer period. Tropical and subtropical areas are more affected. Then expect a deluge of precipitation in regions where rain is usually rare, such as on the west coast of South America, the disruption of the monsoon in Africa and drought anomalies, particularly in the Sahel.
The past eight years have been the hottest on record. Interview with Philippe Gachon, professor in the Department of Geography at UQAM, and researcher at the Center for the Study and Simulation of Climate on a Regional Scale
However, it would be risky to determine the effects of the next El Niño based on past episodes, according to Gachon. Significant factors such as climate change alter the occurrence and characteristics of cycles where El Niño and La Niña alternate.
“C& #x27;is clear, and it is important to note, that the past is no longer a guarantee of the future. »
— Philippe Gachon, professor in the Department of Geography at UQAM
Already, the current extended episode of La Niña is quite special, notes Philippe Gachon. What have we seen recently? California under water, struggling with regular depressions, which is typical of an El Niño phenomenon!
In North America as in Europe, the winter has so far been totally atypical, underlines the expert, who evokes the absence of snow in the Alps and the high temperatures recorded at the beginning of the year in France, in Spain and Germany.
To better understand the particular conditions observed since 2022, it is necessary to take an interest in what is happening in the Atlantic Ocean, i. #x27;one of the oceans most threatened in the long term by global warming.
“What worries me in particular is the Atlantic Ocean. Right now it's jamming the signal. »
— Philippe Gachon, professor in the Department of Geography at UQAM
Although it is smaller than the Pacific, the ocean Atlantic, due to its geographical position and its ability to cause atmospheric blockages, is called upon to play a crucial role in influencing the path and magnitude of storms.
As it warms, the Atlantic Ocean affects atmospheric circulation and upsets some of the responses of El Niño/La Niña phenomena, Gachon explains.
Depending on how the Atlantic reacts, events associated with a shortage or excess of water – droughts, forest fires, heat waves, or conversely precipitation and flooding – will be exacerbated.
One thing is certain, the arrival of El Niño in 2023 will increase the probability of having a much warmer year than 2022, summarizes Mr. Gachon. According to the UK Met Office (Met Office), 2023 will be nothing short of one of the hottest years on record.
Climate experts James Hansen, Makiko Sato and Reto Ruedy have even estimated that the year 2023 could serve as a premise for exceeding, in 2024, the critical threshold of Earth warming of +1.5°C compared to the pre-industrial era.
