Washington- The natural cycle of The Childwhich disrupts weather around the world, is being affected by a warming planet, according to meteorologists.
A new study estimates that an unusual recent turn in the warming-cooling cycle that includes El Niño and its counterpart The Girl may help explain the scientific mystery of why Earth’s already rising temperature soared to a new level in the past three years.
Furthermore, scientists have had to update their way of labeling El Niño and La Niña due to rapid weather changes caused by global warming. Increasingly warmer waters around the world have caused National Oceanic and Atmospheric Administration (NOAA, in English) Modify this month how you calculate when the weather pattern has entered a new cycle. It is likely that more events will be considered La Niña and fewer El Niño due to warming tropical waters.
Earth’s monthly average temperature made a notable jump from the long-term rising trend linked to human-caused climate change in early 2023, and that rise continued through 2025. Scientists have many theories about what’s happening, including an acceleration of greenhouse gas warming, a reduction in particle pollution from ships, the eruption of an underwater volcano, and an increase in solar output.
In a new study published this month in Nature Geoscience, Japanese researchers analyze how the difference in energy entering and leaving the planet – called the Earth’s energy imbalance – increased in 2022. According to scientists, a greater imbalance, or more trapped heat, causes warmer temperatures. Researchers estimate that about three-quarters of the change in Earth’s energy imbalance can be attributed to the combination of long-term human-caused climate change and the shift from a three-year cooling La Niña cycle to a warming El Niño cycle.
What are El Niño and La Niña?
El Niño is a cyclical, natural warming of areas of the equatorial Pacific that alters global weather patterns, while La Niña is characterized by colder than average waters.
Both modify precipitation and temperature patterns, but in different ways. El Niño tends to increase global temperatures and La Niña depresses the increase in the long term.
Las Niñas tend to cause more damage in the United States due to increased hurricane activity and drought, several studies have shown.
Weather cycles
Between 2020 and 2023, Earth suffered an unusual “triple dip” of La Niña without an El Niño in between. In a Niña, warm water adheres deeper, resulting in a colder surface. And that reduces the amount of energy that goes out into space, said study co-author Yu Kosaka, a climate scientist at the University of Tokyo.
He compared it to what happens when people have a fever.
“If our body temperature is high, it tends to emit its energy outwards, and the same thing happens to the Earth. And as temperatures increase, it acts by emitting more energy outwards. And in the three years of La Niña, the opposite happens,” Kosaka explained.
Therefore, more energy is trapped in the Earth, which is converted into heat, he explained. Las Niñas usually correspond to a buildup of one or two years of additional energy imbalance, but this time it was longer, so the difference was more noticeable and included warmer temperatures, Kosaka explained.
“When you transition from La Niña to El Niño, it’s like the lid opens,” releasing the heat, explained former NOAA meteorologist Tom Di Liberto, now with Climate Central.
According to the study’s authors, approximately 23% of the energy imbalance that has caused the recent increase in temperatures comes from this unusually long La Niña pattern, and just over half of the gases come from the combustion of coal, oil and gas. The rest may be due to other factors.
Scientist Jennifer Francis of the Woodwell Center for Climate Research, who was not involved in the study, said the research makes sense and explains a growing energy imbalance that some scientists attributed to accelerated warming.
Change in name
For 75 years, when meteorologists calculated El Niño and La Niña, they were based on the difference in temperature in three tropical regions of the Pacific from normal. An El Niño was 0.5 degrees Celsius (0.9 degrees Fahrenheit) warmer than normal and a La Niña was colder than normal by the same amount.
The problem in a warming world is that what is considered normal is constantly changing.
Until now, NOAA typically used the 30-year average. It updated the 30-year average every decade, which is how often it updates most climate and weather measurements. Then the water warmed so much for El Niño and La Niña that NOAA updated its definition of normal every five years, but that wasn’t enough either, said Nat Johnson, a meteorologist at NOAA’s Geophysical Fluid Dynamics Laboratory.
So NOAA came up with an El Niño index that is relative, starting this month. This new index compares temperatures with those of the rest of the Earth’s tropics. Recently, the difference between the old and new methods has been as much as 0.9 degrees Fahrenheit (°F), and “that’s enough to have an impact,” Johnson said.
This is because what really matters with El Niño and La Niña is the way the waters interact with the atmosphere. And recently the interactions were not consistent with the old labeling, but with the new method, Johnson said.
This will likely mean a little more La Niña and less El Niña than in the old system, Johnson said.
Here comes another El Niño
According to NOAA forecasts, El Niño will develop in late summer or fall of this year. If it occurs soon enough, it could reduce hurricane activity in the Atlantic. But it would also mean warmer global temperatures in 2027.
“When El Niño develops, we are likely to set a new world temperature record,” Woodwell’s Francis says in an email. “‘Normal’ was forgotten decades ago. And with so much heat in the system, everyone should buckle up for the extreme weather it will fuel.”