The powerful El Niño weather phenomenon has contributed, along with climate change, to raising global temperatures to new highs in recent months.
Now it is over, scientists from the Australian Bureau of Meteorology indicated on Tuesday.
The Pacific Ocean cooled “substantially,” according to data collected last week by this organization.
For its part, the US National Oceanic and Atmospheric Administration (NOAA) also predicted a week ago that El Niño is coming to an end and that it will do so between the months of April and June.
Matches the World Meteorological Organization (WMO), which estimates that there is an 80% chance of neutral conditions (neither El Niño nor La Niña) between this April and June.
The last episode of El Niño, which began in June of last year, brought warmer waters to the surface of the Pacificwhich added additional heat to the atmosphere and caused global temperatures to rise, breaking historical records month after month.
What may happen in the coming months is still uncertain, researchers say.
The doubts left by El Niño
Recent monthly high temperature records globally have led some scientists to fear that the world may be entering a crisis. a new, even faster phase of climate change.
Experts believe that the months after the end of El Niño will offer a more accurate indication of whether or not recent high temperatures are due to this acceleration of global warming.
Every few years, the arrival of El Niño causes major changes in the climate in many parts of the world.
The generalization of warmer waters rising to the surface off the coast of Peru is related to the increase in droughts and floods in different parts of the world.
The full name of this pattern is El Niño-Southern Oscillation or ENSO.
It is marked by three different phases: warm El Niño, neutral conditions and its opposite stage, a colder period called La Niña.
The El Niño phenomenon that is now ending began in June 2023 and reached its peak in December.
Warmer water in the Pacific helped raise average temperatures to new highs on the planet and this March the monthly record was broken for the tenth consecutive month.
But now – and perhaps faster than expected – El Niño is coming to an end.
The key question is what will happen nextand scientists are divided on how to answer it.
US researchers recently stated that there was a 60% chance that La Niña would develop between June and August, and an 85% chance that this would happen until the fall.
Experts at the Australian Bureau of Meteorology believe such predictions should be made with caution and expect the neutral conditions to last at least until July.
“As current global ocean conditions have never been seen before, predictions based on past events of how ENSO could develop in 2024 may not be reliable,” they said in a statement.
According to researchers, whether La Niña forms or not is of great importance.
This phenomenon may have a significant impact on the formation of storms and hurricanes and some experts predict that its arrival would herald a very active hurricane season in the Atlantic.
The cooling effect of La Niña may also slightly slow the pace of global warming.
This could indicate that the record temperatures experienced last year are not evidence that the world has entered a faster warming phase.
Why do El Niño and La Niña form?
Scientists aren’t sure what exactly starts the process. But sometimes, air pressure conditions change over the equatorial Pacific, affecting the southeast trade winds – from the intertropical regions – that normally blow from east to west.
Some consider that the Earth’s rotation could affect the movement of these winds, which act on the surface of ocean water.
Although it is known that the wind is the triggerthere are different theories about why this wind is altered, among them the one that maintains that variations in solar activity cause different heating on the planet and, in turn, different pressures.
Be that as it may, during El Niño the trade winds weaken, so less water moves westward, so the central and eastern part of the Pacific warms more than usual.
Sometimes a very sudden cooling follows and it becomes La Niña, although there can also be Niñas when there is no Niño, according to experts.
During La Niña the winds get strongerso the mass of water heated by the sun is pushed westward.
Meanwhile, in the eastern Pacific, deep, cold water rises to replace warm water.
El Niño does not have a fixed period: usually lasts between 9 and 12 months and its intensity can also vary.
The development of this phenomenon is usually monitored by international meteorological centers that use climate models and satellite observations to predict its appearance and potential impacts.
Likewise, La Niña does not follow a fixed calendar and its frequency and intensity can vary.
La Niña events may last from 9 months to 3 yearsand its prediction also depends on climate observations and advanced weather models.
Scientists continue to study both phenomena to improve predictions and better understand their impact on global climate change.
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