If someone had said for a hundred years that it would be possible to predict the behavior of an entire ocean months before it changed the climate on several continents, it would probably be called a dreamer.
Today, that happens every day.
Weather centres around the world are monitoring, practically in real time, the temperature of the Pacific Ocean, the speed of the winds, the formation of clouds and even the movement of sea currents. Each time, supercomputers process millions of information to answer a question that interests farmers and airlines: Is the weather about to change?
When these answers point to the same path, a name usually gains space in the headlines: The Child.
Although it is frequently cited in reports about droughts, floods or heat waves, the phenomenon still generates many doubts. After all, why can a warming in the Pacific Ocean influence the climate in Brazil? How can scientists perceive this even before the first impacts appear? And what is the role of Artificial Intelligence in this process?
To answer these questions, one must start with a place that seems quiet when seen from space, but which exerts a huge influence on life on Earth: the Pacific Ocean.
An ocean that helps control the climate of the planet
The Pacific Ocean occupies almost one third of the Earth's surface. Besides being the largest ocean on the planet, it functions as a gigantic heat reservoir.
For much of the time, there is a balance between water temperature and the winds blowing over its surface. These winds push the warmest waters towards Asia and Oceania, while colder waters rise near the coast of South America. This movement happens continuously and helps to keep the circulation of the atmosphere running relatively stable.
But nature doesn't always follow the same script.
At certain times, the winds begin to lose strength. With less intensity to push the hot waters, part of that heat remains in the central and eastern Pacific region. Gradually, a huge range of the ocean begins to record temperatures above average.
That's when the El Niño is born.
At first glance, the difference seems small. In some cases, the temperature increases only one or two degrees Celsius. In a pool, perhaps no one could perceive this change. In the largest ocean on the planet, however, this small variation represents a gigantic amount of energy being released into the atmosphere.
And it is precisely this energy that begins to reorganize the climate in different parts of the world.
How to explain El Niño to a child?
Imagine a huge pool on a summer day.
The water is practically at the same temperature throughout the pool. Now imagine that someone turned on a giant heater in just one corner.
After a while, that hot water starts to spread. The currents change, the temperature stops being uniform and the whole pool starts to work differently.
Something similar happens with the Pacific Ocean.
When a part of it gets warmer than it should, the air above the water also warms up. This air rises, the winds change direction, the clouds start to form elsewhere and the climate changes in several countries at the same time.
That is why a phenomenon that happens thousands of kilometers from Brazil can change the amount of rain on Brazilian cities.
Why does that change the climate from places so far away?
This may be the most curious part of the whole story.
Earth's atmosphere functions as a connected system. Air is in constant motion, transporting heat and humidity between continents and oceans.
When a very large region of the Pacific warms beyond normal, it modifies this balance. Winds change in intensity, areas where it usually rains become drier and regions accustomed to quiet periods can record more intense storms.
It's like pushing the first piece of a domino row. The movement starts at a single point, but its effects appear far away from there.
Meteorologists call this set of changes climate teleconnections: changes in one part of the planet that cause consequences in another, even separated by thousands of kilometers.
What's going on around here?
Although El Niño is a single phenomenon, it does not affect all Brazilian regions in the same way.
Those living in the South usually feel its effects first. In many episodes, the volume of rain increases significantly, raising the risk of floods, slips and time. Just remember some of the extreme events recorded in the region in recent decades to realize that climate behavior can change a lot during these periods.
In the North and in part of the Northeast, the opposite usually happens. The reduction of rains favors longer droughts, rivers with lower levels and difficulties for activities that depend directly on water, such as agriculture.
In the Midwest and much of the Southeast, the most perceived impact is usually the increase in temperatures and heat waves, although each El Niño event has its own characteristics.
This explains why two Brazilian cities can live completely different situations while the same phenomenon is happening in the Pacific Ocean.
For a long time, predicting El Niño was almost impossible
Today it seems natural to hear forecasts for the coming months, but it has not always been so.
Until a few decades ago, researchers relied mainly on measurements made by ships crossing the Pacific. Data took weeks to reach the research centers and represented only small points in a gigantic ocean.
It was like trying to understand the traffic of a city by looking at just one street.
Often, when scientists realized that El Niño was forming, its effects had already begun.
Technology has completely changed that scenario.
How science began to see the ocean in real time
At this very moment, while this article is being read, dozens of satellites continually observe the surface of the planet.
They measure the temperature of the oceans, monitor the formation of clouds, record changes in the direction of the winds and monitor the amount of water vapour present in the atmosphere.
But they don't work alone.
Spreading across the Pacific Ocean there is an international network of scientific buoys that remains running twenty-four hours a day. These floating stations record water temperature, atmospheric pressure, wind speed and other fundamental information to understand the behavior of the ocean.
In some cases, oceanographic vessels also take action to perform deep measurements that satellites cannot observe.
Each of these information represents only a small piece of the puzzle. When all are gathered, a much clearer image begins to emerge than is happening on the planet.
Where do the supercomputers come in?
Collecting data is just part of the job.
The real challenge is to turn billions of measurements into reliable forecasts.
That's where the supercomputers come in.
These machines perform extremely complex mathematical models capable of simulating the behavior of the atmosphere and the oceans for the following months.
Instead of producing just one forecast, they test thousands of different scenarios.
What happens if the temperature rises more than half a degree?
What if the winds lose intensity earlier?
What if the ocean cools in the next few weeks?
By comparing all these scenarios, researchers can estimate the probability of formation of El Niño and its possible intensity.
There is no absolute certainty when it comes to the climate, but today the forecasts are much more precise than they were a few decades ago.
Artificial Intelligence didn't replace meteorologists — it went on to work alongside them
Whenever you talk about Artificial Intelligence, a lot of people imagine computers making decisions on their own.
In meteorology, reality is quite different.
Climate models continue to be based on the laws of physics. What has changed is the ability to analyze a gigantic amount of information in much less time.
AI can identify patterns hidden in decades of climate data, compare similar events and point to signs that could go unnoticed in a traditional analysis.
It works as a second opinion extremely fast.
While physical models show how the atmosphere should behave, Artificial Intelligence helps to recognize trends, find relationships between different variables and reduce uncertainty in predictions.
Instead of replacing science, it expands its ability to see patterns in an incredibly complex system.
What to expect from El Niño in 2026?
Over 2026, institutions responsible for climate monitoring began to observe a persistent warming of the waters of the Equatorial Pacific. At the same time, changes in wind circulation and other indicators began to reinforce that the ocean was entering a different phase.
No scientist makes this kind of prediction looking at only one given. Consensus arises when different models developed by research centers around the world begin to point to the same trend.
That's exactly what happened.
As new measurements confirmed the warming of the ocean, the confidence that El Niño would reinfluence the climate in various regions of the planet also increased. As in any weather forecast, details of intensity and duration continue to be refined as new information is incorporated into the models.
This means that monitoring weather reports remains essential. Science can predict trends well in advance, but the behaviour of the atmosphere remains dynamic and is constantly updated.
A natural phenomenon, explained by cutting-edge technology
El Niño is an excellent example of how science and technology walk together.
What previously depended only on observing few ships today involves satellites, ocean-distributed sensors, international research networks, supercomputers and artificial intelligence systems capable of analyzing gigantic volumes of data in a matter of minutes.
More than predicting rain or heat, this work helps farmers plan crops, governments organize preventive actions, companies reduce risks and millions of people prepare for extreme weather events.
Perhaps this is the most fascinating part of this whole story: a phenomenon that begins silently in a distant ocean can influence the routine of entire cities across the planet. And thanks to technology, today we can see these signs long before they reach us.