- By Matt McGrath
- Environment Correspondent
A natural weather phenomenon known as El Niño has begun in the Pacific Ocean, adding heat to a planet already warming under climate change.
American scientists confirmed that El Nino had started. Experts say this could make 2024 the world’s hottest year ever.
They fear this could help the world pass a key 1.5C warming milestone.
It will also affect global weather, bringing drought to Australia, more rain to South America and weakening India’s monsoon.
This phenomenon will last until next spring, after which its effects will subside.
For months, researchers have been increasingly confident that an El Niño event is about to emerge in the Pacific Ocean.
„It’s increasing now, and we’ve had signs in our forecasts for months, but in terms of intensity it looks like it’s going to peak at the end of the year,” said Adam Scaife, head of long-range forecasting. UK Met Office.
„A new record for global temperatures next year is certainly plausible. It depends on how big El Niño becomes – a big El Niño later this year gives a higher chance of a new record, global 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 is properly called, has three distinct phases: warm, cold, or neutral.
A warming condition known as El Niño occurs every two to seven years and warm water from the coast of South America rises to the surface, spreads across the ocean, and pushes significant amounts of heat into the atmosphere.
The hottest years on record, 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 determine this warm period.
For scientists in the US, by their definition, the ocean must be 0.5C warmer than normal per month, the atmosphere must be seen to respond to this warming, and there must be evidence that the phenomenon is ongoing.
These conditions were met in May. The US National Oceanic and Atmospheric Administration (NOAA) said in a statement that „El Niño conditions are present”.
„It’s a very weak signal. But we’re starting to see these conditions, and we believe they will continue to intensify,” said Michelle L’Heureux, a scientist at NOAA.
„Our weekly value was actually 0.8C this past week, which is still strong.”
Researchers believe there is an 84% chance the event will exceed moderate strength by the end of the year.
They also say there is a one-in-four chance of exceeding 2C at the peak of the event, which would fall within „Super El Niño” territory.
The impact of El Niño may be delayed by a few months but will be felt around the world.
Researchers expect drier weather in parts of Australia and Asia and a weakening monsoon in India. South American states will be wet this coming winter. El Niño generally exacerbates drought in Africa.
If experience is anything to go by, this upcoming weather event will have a huge human and economic cost.
Strong El Niño storms and floods in 1997-98 cost more than $5 trillion, with about 23,000 deaths.
There is also a strong chance that this year’s version will make 2024, surpassing 2016 as the world’s hottest year ever.
Global temperatures are currently 1.1C above the average for the period 1850-1900.
But an El Niño event could add up to 0.2C to that figure, pushing the world into uncharted temperature territory and close to breaking the benchmark 1.5C safety rail, a key component of the Paris climate agreement.
Researchers recently reported that temporarily breaking this limit is more likely than not in the next few years.
„We’re really likely to see global average temperatures that could become a regular thing in five to ten years, so it gives us that kind of portal into the future.” Michelle L’Heureux said.
„I think that’s why it’s alarming for some people, because these are our new limits. And El Nino is accelerating that.”