Powerful El Niño's ripple effects could eventually reach Estonia
A potentially record-setting El Niño is strengthening in the Pacific, as researchers warn its impacts, including global temperature spikes, could reach far beyond the tropics.
The equatorial Pacific is already unusually warm, and University of Tartu (TÜ) climate science professor Piia Post said the developing event may surpass all previous records. Because current ocean temperatures have no close historical comparison, however, long-term forecasts remain uncertain.
"Temperatures are already so high that there is no previous El Niño year to use as a comparison," Post said.
Known formally as the El Niño–Southern Oscillation (ENSO), the phenomenon describes a recurring interaction between the ocean and atmosphere that influences weather patterns worldwide.
Although it develops thousands of kilometers from Estonia, the Pacific region acts as one of Earth's largest climate engines, meaning major temperature shifts there can affect weather far beyond the tropics, from temperatures to precipitation.
Peak still to come
Under normal conditions, strong trade winds push warm surface waters westward toward Asia, while colder deep water rises off South America's western coast, cooling the atmosphere above it.
During El Niño, those winds weaken, allowing unusually warm water to remain in the eastern Pacific and transfer more heat into the atmosphere.
"Because the surface water is warm, it releases large amounts of energy into the atmosphere, which is reflected in rising global temperatures," Post explained.
Researchers measure El Niño strength using temperature anomalies in the Niño 3.4 region of the Pacific Ocean.
On the Relative Oceanic Niño Index (RONI) used by the U.S.' National Oceanic and Atmospheric Administration (NOAA), a deviation of 1.8 degrees Celsius is considered a strong event, while 2.3 degrees marks a very strong one.
The current anomaly is already around 2 degrees, but the peak typically arrives toward the end of the year, usually in November or December. Post said the event is unlikely to weaken before then.
The strongest El Niño events on record to date occurred in 1997 and 2015, when ocean temperatures reached nearly 3 degrees above normal. Its current development, however, is already running about half a degree warmer than those earlier events during the same stage.
"If we are already at 2 degrees now, we are exceeding all previously recorded strong El Niño events," the professor added.
Forecast models suggest the Niño 3.4 region could eventually reach temperatures up to 3.6 degrees above normal, exceeding the 2015–2016 record by about 0.8 degrees.
The resulting boost to global temperatures, in turn, could push the planet's average temperature to as much as 1.7 degrees Celsius above preindustrial levels.
Effects could reach Estonia indirectly
El Niño disrupts tropical atmospheric circulation, shifting rainfall patterns along the equator. As a result, areas that normally receive heavy rain may experience drought, while traditionally dry regions may face flooding.
The strongest direct impacts are expected in parts of the Pacific, North America, Australia and Africa.
Europe will be less directly affected, as its weather is largely shaped by the Atlantic Ocean, but researchers say El Niño's indirect effects can still reach the region — in terms of both weather and the economy.
Extreme weather in areas connected to Europe through global supply chains can raise prices for goods and services. Changes in atmospheric circulation can influence the Atlantic jet stream, altering storm paths that eventually affect Europe.
"Atmospheric circulation will change and that will take time, with effects appearing with a several-month delay," Post said.
However, those Atlantic impacts are harder to predict than ENSO itself, whose regular patterns allow researchers to make seasonal forecasts in the regions most directly affected.
Climate change adding a boost
Researchers are also studying whether human-caused climate change is altering El Niño itself. There is no clear answer yet, but because global warming is unevenly distributed around the world, that alone is already changing atmospheric circulation patterns and shifting storm tracks.
The greenhouse effect, which has increased the heat trapped near Earth's surface, has also added more energy to the climate system than ever before, increasing the intensity of temperature-driven weather processes and phenomena.
"Because the planet has already warmed, temperatures have also risen in the Pacific, giving the phenomenon even more energy," Post said.
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Editor: Aili Vahtla
