A natural weather event known as El Niño has begun in the Pacific Ocean and is likely to add heat to a planet already warming from climate change.
American scientists confirmed that El Niño had started. Experts say 2024 will likely be the hottest year on Earth.
They fear it will help push the world past an important 1.5°C warming milestone.
It will also affect the world’s weather, with possible drought in Australia, more rain in the southern US and a weakening of the Indian monsoon.
The event is likely to last until next spring, after which its effects will wear off.
For months, researchers have been increasingly confident that an El Niño event would originate in the Pacific Ocean.
“It’s ramping up now. There have been signs in our forecasts for several months now, but it really looks like it’s going to peak in terms of intensity at the end of this year,” said Adam Scaife, head of long-term forecasts at the UK Met Office .
“A new record for world temperature next year is certainly plausible. It depends on how big the El Niño turns out to be – a big El Niño at the end of this year gives a high chance that we will have a new record, the world temperature .” in 2024.”
This natural phenomenon is the most powerful fluctuation in the climate system anywhere on Earth.
The El Niño Southern Oscillation, or ENSO, as it’s rightly called, has three distinct phases: warm, cold, or neutral.
The hot phase, called El Niño, occurs every two to seven years and sees warm water rise to the surface off the coast of South America and spread across the ocean, propelling significant amounts of heat into the atmosphere.
Record warm years, including 2016, the world’s hottest on record, usually occur the year after a powerful El Niño event.
Weather agencies around the world use different criteria to decide when this hot phase will arrive.
For scientists in the US, their definition requires that the ocean be 0.5°C hotter than normal for a month, that the atmosphere must respond to this heat, and that there must be evidence that the event is continuing.
These conditions were met in the month of May. In a statement, the US National Ocean and Atmospheric Administration (NOAA) said “El Niño conditions are present”.
“This is a very weak signal, but we believe we are starting to see these conditions and they will continue to increase,” said Michelle L’Heureux, a scientist at NOAA.
“Our weekly value is actually 0.8C for the past week, which is even stronger.”
The researchers believe this event has an 84% chance of exceeding moderate strength by the end of this year.
They also say there’s a one in four chance of this event exceeding 2°C at its peak, entering “super El Niño” territory.
The effects of the onset of El Niño are likely to lag for several months,
but will be felt around the world.
Researchers expect this to include drier weather in Australia and parts of Asia, with a possible weakening of the monsoon in India. The southern states of the US are likely to be wetter this coming winter. El Niño normally amplifies drought in Africa.
If experience is anything to go by, this approaching weather event will come at a great human and economic cost.
The strong El Niño in 1997-98 cost more than $5 trillion with about 23,000 deaths from storms and floods.
There’s also a good chance that this year’s version will push 2024 past 2016 as the world’s warmest year.
Global temperatures are currently hovering around 1.1°C above the 1850-1900 average.
But an El Niño event could reach as high as 0.2°C at that figure, pushing the world into an unknown temperature region and nearly closing the symbolic 1.5°C guardrail, a key part of the Paris climate agreement. broken.
Researchers recently said it’s more likely than not to temporarily cross this line in the next few years.
“We’re likely to see global average temperatures that could become more of a normal thing in five to 10 years, so it does give us such a portal into the future.” said Michelle L’Heureux.
“And I think that’s why it’s alarming to some people, because these are our new thresholds. And El Niño gives an accelerator to that.”