Scientists forecast that this year’s El Niño could become the strongest in nearly 150 years of observations, with Pacific sea-surface temperature anomalies potentially reaching record levels. Michał Brennek of the Institute of Geophysics at the Polish Academy of Sciences cautions, however, against linking the phenomenon directly to individual heatwaves or other extreme weather events in Poland. For Polish consumers, its effects are more likely to be felt indirectly through higher prices for commodities such as rice, sugar and coffee produced in tropical regions.
– What is El Niño? Scientifically speaking, it is an oscillation. In less technical terms, it is a kind of swing or pendulum that redistributes warm water across the tropical Pacific in an irregular cycle. During El Niño conditions, a positive sea-surface temperature anomaly develops off the western coasts of the Americas, meaning the ocean becomes warmer than usual. This, in turn, changes wind patterns over the world’s largest ocean. As a result, not only atmospheric circulation but also the transport of moisture changes across an enormous area – Michał Brennek of the Department of Atmospheric Physics at the Institute of Geophysics, Polish Academy of Sciences, explains in an interview with Newseria.
He stresses that El Niño should not be confused with climate change. It is a natural phenomenon whose traces can be found in corals dating back thousands of years.
– As the climate changes, the Earth system accumulates more energy, and most of that excess energy is absorbed by the oceans. They have a stabilising effect, but because they absorb energy, there is now an excess of it stored in the ocean. We can see this in record sea-surface temperatures. El Niño is being superimposed on that background, meaning the positive temperature anomaly in the tropical eastern Pacific is starting from a higher baseline – Brennek says. – This year’s El Niño is unprecedented because of the amount of energy accumulated in the ocean and the already very high sea-surface temperature anomalies.
El Niño typically raises the global average temperature in the following year by around 0.1–0.2°C. Researchers explain that the phenomenon does not directly add new heat to the planet. Instead, it redistributes heat between the ocean and the atmosphere and between different regions.
– Although that may not sound like much, we need to remember that we are looking at a global phenomenon. Even such small changes in the global average temperature tell us a great deal about the scale and significance of what is happening – the expert explains.
The US National Oceanic and Atmospheric Administration has been warning since June about an El Niño event that is developing unusually rapidly this year.
The weekly Niño 3.4 index reached +1.7°C in mid-June, while a reservoir of heat beneath the ocean surface was almost twice as large as at the same stage of El Niño development in 2023. Local temperature anomalies of as much as 6°C have been recorded at depths of 50–150 metres.
Fourteen climate models indicate that the anomaly could reach a level not previously recorded in nearly 150 years of observations. Scientists say this could become the strongest El Niño ever observed.
– We expect not only a very high sea-surface temperature anomaly. There is also an entire reservoir of energy below the ocean surface that will continue feeding those temperatures, so the phenomenon is very likely to persist – says the scientist from the Institute of Geophysics at the Polish Academy of Sciences.
When the ocean releases more heat into the atmosphere, wind patterns change. This can lead, among other effects, to droughts in Indonesia and Australia and heavy rainfall along the western coast of South America.
Droughts in tropical regions can reduce yields of many major crops, including rice, coffee, sugar and oil palm.
– El Niño changes the local transport of moisture. Some places will become drier, while others will become wetter. For Peru, whose coastal waters are normally much colder and whose economy depends heavily on rich fisheries and large-scale fishmeal production, this can cause serious disruption. We are also talking about cocoa, coffee and palm oil, which is used virtually everywhere in the food industry. The global distribution of crop yields will change and, inevitably, the prices of these commodities will rise sharply – Brennek explains.
Economic analyses indicate that a strong El Niño could increase global food prices by around 5%, while its economic consequences could persist for years.
– A shift in weather patterns across the tropical Pacific has an enormous impact on the global economy. We are talking about problems affecting agricultural and food systems across large parts of the world, so we should expect considerable price volatility – the expert says. – For Poland, a strong El Niño mainly means economic consequences in the form of either shortages or higher prices for agricultural products, including animal feed. During the previous major El Niño, we also paid much more for confectionery products, including chocolate.
He also emphasises that in Poland it is difficult to establish a clear link between El Niño and specific weather events.
– Paradoxically, the El Niño signal in Poland is very weak and is often noticeable only in winter, when we may experience late cold spells. The mechanism that transports excess energy from the tropical Pacific towards our region is heavily modified by what happens over the North Atlantic. That is the main body of water influencing Poland’s weather – Michał Brennek explains.
– Some events occurred during periods of strong El Niño, such as the 1997 flood, but that is a correlation rather than a cause-and-effect relationship and certainly requires further research. At the time, the positive temperature anomaly in the Mediterranean Sea – which acted as a source of moisture – and the Genoa low, which transported humid air masses towards Poland, were much more important factors.
