When the ocean changes, the world changes with it. Perhaps the greatest lesson is also the simplest, because El Niño Ocean Warming is pushing the planet into uncharted territory by adding another burst of heat to an ocean already warmed by decades of human-caused climate change.
The planet is entering a dangerous new climate chapter with the heat and moisture released from the Pacific is warping the weather patterns around the world. From Indonesian wildfires and dangerous smoke to floods, droughts, food insecurity and marine heatwaves, the effects could ripple across the planet.
El Niño Ocean Warming: A Record-Warm Ocean Meets a Powerful El Niño
There are moments when nature seems to whisper a warning. Then there are moments when the planet breaks a record so striking that the warning becomes impossible to ignore. The world may now be approaching one of those moments.
The world’s oceans are already running exceptionally warm after decades of human-caused global warming. And a powerful El Niño that is developing across the tropical Pacific is raising the prospect of extreme weather and mounting pressure on marine ecosystems.
Together with the enormous amounts of heat released from the ocean into the atmosphere, these forces could push the global temperatures to extraordinary levels and disrupt weather patterns across vast parts of the planet. The result could be a year of extraordinary weather – intense heat and drought in some regions, torrential rainfall and flooding in others, and the growing stress on ecosystems that are already struggling to adapt.
As climate scientist Daniel Swain of the University of California puts it, the tropical Pacific has an “outsized ability to affect the global climate.” And now that enormous climate engine is turning up the heat, which is almost certain the world will warm past 1.5C.
A Record-Warm Ocean Meets a Powerful El Niño
On 22 August 2026, the average surface temperature of the global ocean outside the polar regions reached 21.1°C (70°F), narrowly surpassing the previous record of 21.09°C set in March 2024. The difference may appear tiny, only a fraction of a degree. But the timing makes the record especially troubling.
Global ocean temperatures normally reach their annual peak around March or April. Yet in 2026, temperatures continued climbing into September – when they would normally be declining. And there is another reason scientists are watching closely. El Niño is strengthening.
That means an already unusually warm ocean is receiving another powerful pulse of heat from one of the most influential regions of the global climate system. This is why the story is much bigger than a single temperature record. The ocean’s baseline is changing.
What Exactly Is El Niño and How it can Make a Hot Year Even Hotter?
El Niño is a natural climate phenomenon in which unusually warm surface waters develop across the central and eastern tropical Pacific. It generally develops every two to seven years, although each event is different in strength and geographical impact.
But the Pacific is not an isolated body of water. Its enormous stores of heat influence winds, rainfall and atmospheric circulation far beyond the region itself. Changes in the tropical Pacific can affect weather patterns across Asia, Australia, Africa, Europe and the Americas.
Think of the tropical Pacific as a giant climate engine or switch. When its temperature changes dramatically, atmospheric circulation responds and the effects can travel thousands of kilometres across the planet. As one climate scientist has described it, El Niño is like dropping an enormous rock into a pond: even places far from where it lands can feel the resulting waves. The important point is that El Niño is natural. What has changed is the world in which it is occurring.
El Niño is not the cause of long-term global warming. Instead, it is a natural climate cycle operating on top of a warming world. Human activity has raised the underlying temperature of the atmosphere and oceans, while El Niño can temporarily add another layer of heat.
As Swain describes it, El Niño can act like a “mini, sudden climate change” on top of the much larger, slower climate change already underway. That combination is what makes the current situation so concerning.
Major Global Effects of El Niño
El Niño has two major global effects. The first is heat. During a strong El Niño, heat stored in the tropical Pacific is transferred into the atmosphere. That can raise global air temperatures and make an already warm planet even hotter.
The second is rainfall disruption. El Niño changes atmospheric circulation and shifts where and when rain falls. Some places can experience intense rainfall and flash flooding, while others face severe drought. These effects become more pronounced against the backdrop of human-caused warming.
A warmer atmosphere can hold more moisture, potentially intensifying rainfall when conditions favour storms while also contributing to more severe drying when rainfall is suppressed. The result is a climate system capable of swinging between extremes. Heat – Flood. Drought – Storm. And sometimes several of them in rapid succession, as El Niño is now developing over a planet that is already considerably warmer than it was before the industrial era. That distinction matters.
The Ocean Has Been Protecting Us – But at a Cost
The ocean covers more than 70% of Earth’s surface. It is one of the planet’s greatest climate regulators and humanity’s enormous heat absorber. More than 90% of the excess heat trapped by greenhouse gas emissions has been absorbed by the world’s oceans. That has slowed the pace of atmospheric warming.
But the ocean is paying the price. Every additional unit of heat stored in seawater affects the physical, chemical and biological systems that depend upon it. Warmer seawater expands, contributing to sea-level rise. Hotter oceans can provide additional energy and moisture to some weather systems.
Marine heatwaves can place ecosystems under severe stress. And species that evolved within particular temperature ranges may be forced to move, adapt or disappear from places where they have lived for generations. The ocean has acted as a giant buffer against even faster atmospheric warming. But a buffer can only absorb so much.
When the Sea Becomes a Furnace
For marine life, temperature is not merely a number. It can determine whether an ecosystem survives. Coral reefs are among the clearest examples. Prolonged heat stress can cause corals to expel the microscopic algae that provide them with much of their energy. The result is coral bleaching. If extreme heat persists, entire reef communities can suffer severe damage. But coral reefs are only one part of the story.
Fish migrate. Plankton populations change. Predators can lose familiar sources of food. Seagrass meadows can become stressed. Entire marine food webs can be reorganised. And eventually, ecological changes become human changes.
Fisheries, tourism, coastal economies and food security all depend on healthy oceans. The supplied material notes that global marine heatwave days have increased dramatically since the early 1990s. The ocean, in other words, is not experiencing isolated hot days. It is experiencing a changing climate.
What Happens When a Hot Ocean Meets a Storm?
The ocean and atmosphere are inseparable. Ocean temperatures influence the atmosphere above them, while atmospheric circulation affects the ocean below. Warm seawater can supply some storms with additional moisture and energy. That does not mean every storm automatically becomes stronger because the ocean is warmer. Climate systems are far more complicated than that.
But warmer oceans can increase the potential for some extreme events to become more intense. And because the oceans cover most of Earth’s surface, changes in one region can influence weather thousands of kilometres away. What happens in the Pacific does not necessarily stay in the Pacific.
Europe’s Seas Are Feeling the Heat Too
The extraordinary warmth is not confined to the tropical Pacific. The supplied material reports exceptionally high sea-surface temperatures around Europe’s Atlantic coast and the western Mediterranean, accompanied by widespread marine heatwave conditions.
For marine ecosystems, persistent unusual warmth can be devastating. Species may move toward cooler waters. New species may appear in places where they were previously rare. Others may decline. And eventually, those ecological changes can become economic changes for coastal communities.
The temperature of the sea therefore is not simply an environmental statistic. It can influence what people catch, what they eat, what they grow and how they earn a living.
Heat in the Ocean Becomes Water on the Coast
There is another consequence that can easily be overlooked. When seawater warms, it expands. This process, known as thermal expansion, contributes to sea-level rise. On its own, seawater expansion may sound insignificant. But the world’s oceans contain billions of tonnes of water and cover more than 70% of the planet.
Small physical changes become enormous when multiplied across the entire ocean. Add melting glaciers and ice sheets, and the long-term threat becomes even greater. For low-lying islands and coastal cities, rising seas mean greater risks from flooding, erosion, saltwater intrusion and storm surges. The heat stored in today’s ocean can therefore become tomorrow’s coastal crisis.
Can We Blame It All on El Niño?
This is perhaps the most important question. But the answer is: No. El Niño can influence global temperatures, rainfall, drought, storms and fires. But it is not responsible for the underlying warming of the planet. That comes primarily from the long-term accumulation of greenhouse gases produced by human activities, particularly the burning of fossil fuels. This distinction matters. El Niño will eventually weaken and disappear. The underlying climate change will not.
A strong El Niño can temporarily push global temperatures higher. It can amplify certain weather extremes and shift rainfall patterns. But climate change is raising the baseline on which all of this happens. It is like raising the floor beneath the entire climate system. When El Niño arrives, it is adding another layer of warmth to an already hotter world.
El Niño Is Natural. The Heat Behind It Is Not Entirely Natural.
This is the central story. El Niño is part of Earth’s natural climate system. Human-caused global warming is changing the conditions in which that natural cycle operates. A hotter atmosphere can hold more water vapour. A warmer ocean contains more heat.
Marine ecosystems are already under pressure. Glaciers and ice sheets are losing mass. Sea levels are rising. Against this background, a powerful El Niño can act as an additional shock. That is why the same El Niño that might once have produced a particular pattern of weather can now unfold on a fundamentally warmer planet.
The Most Worrying Question Is What Comes Next
Perhaps the most unsettling part of the latest ocean record is not simply that it happened. It is when it happened. Ocean temperatures normally reach their annual peak around March or April. Yet the new record arrived in August, while El Niño was still developing. That raises an uncomfortable question: If the ocean is already breaking records before El Niño reaches its full strength, what happens if the warming intensifies further?
Scientists will be watching closely. The coming months could reveal just how strongly the natural El Niño cycle interacts with the much larger human-driven warming trend.
A Year of Extraordinary Weather: Why This El Niño Matters So Much
El Niño’s influence will not look the same everywhere. Some regions may experience prolonged heat and drought. Others could face unusually heavy rainfall, flash floods and powerful storms. The shifting atmospheric circulation can move rainfall away from places that depend upon it while concentrating it elsewhere.
That creates a dangerous climate paradox: Too much water in one place. Too little in another. And all of this is happening against a background of long-term global warming. This is what makes the current El Niño so important. It is not acting on a stable planet. It is acting on a planet whose atmosphere and oceans have already been heated by human activity.
The developing El Niño is already being described as exceptionally strong. Its strength is measured partly by how much warmer-than-average the tropical Pacific becomes. The warmer the waters in the key monitoring region off South America, the stronger the El Niño classification.
The strongest previous events include 1982–83, 1997–98 and 2015–16. El Niño events typically reach their peak around November and December. But the current event is already showing extraordinary warmth for this stage of its development and is expected to influence global weather into early 2027.
That has raised concerns that temperature records could fall again. But global temperature is only one part of the story. The more immediate danger for many communities may come through rainfall, drought, fire and food production.
Indonesia: When Dry Weather Turns Forests Into Fire
Indonesia provides a dramatic example of how El Niño can transform atmospheric changes into a devastating crisis on the ground. Wildfires that began smouldering in Indonesian rainforests and peatlands earlier in the year expanded rapidly as dry conditions intensified.
By June, about 1,000 square kilometres had reportedly burned. The affected area then expanded dramatically during July. The connection with El Niño is rooted in atmospheric circulation. Normally, warm, moist air rises over the warm waters around Indonesia. As that air rises, it releases moisture and helps support the region’s famously wet conditions. During a strong El Niño, the centre of that rising motion shifts eastward toward the tropical Pacific.
The result can be drier conditions over Indonesia. For forests and peatlands already exposed to human-caused fires, that drying can create dangerous conditions in which flames spread rapidly. Slash-and-burn agricultural fires that might otherwise remain manageable can become uncontrollable. And when tropical peatlands burn, the consequences extend far beyond the immediate fire zone.
When Smoke Becomes a Health Crisis
The damage does not stop at the forest edge. Wildfire smoke can spread across communities, filling the air with dangerous pollutants and creating serious respiratory problems. Children and older people are particularly vulnerable.
Communities living close to burning forests can face days or weeks of hazardous air quality, while people farther away may also be affected as smoke travels with atmospheric currents. The human cost of El Niño therefore cannot always be measured in degrees Celsius.
Sometimes it is measured in the number of people struggling to breathe. The Indonesian experience is a reminder that climate patterns are not abstract scientific phenomena. They can determine whether the air outside a family’s home is safe to breathe.
From Drought to Food Insecurity
Fire is only one consequence of changing rainfall. Agriculture depends on predictable water. When El Niño shifts rainfall away from farming regions, crops can fail, livestock can suffer and food prices can rise. In some places, excessive rainfall can destroy crops through flooding. In others, prolonged dryness can leave fields without enough water. This creates one of the most dangerous contradictions of El Niño: Too much water in one place. Too little in another.
The consequences can spread through food markets and supply chains long after the original weather event has ended. The United Nations World Food Programme has warned that a strong El Niño could push millions more people into acute food insecurity. For vulnerable communities, especially those already facing poverty, conflict or water shortages, another major climate shock can be devastating.
El Niño Does Not Produce the Same Weather Everywhere
One of the most important things to understand about El Niño is that its effects are not uniform. The same climate phenomenon that brings drought to one region can bring destructive rainfall to another. El Niño changes the position and strength of atmospheric circulation and the jet stream.
Those changes influence where storms travel and where rainfall concentrates. Some regions become wetter. Others become drier. Some experience extreme heat. Others may receive temporary relief from drought. That complexity is why scientists do not simply say, “El Niño causes floods” or “El Niño causes drought.” It depends on where you are and how the atmosphere responds.
The United States: Floods in Some Places, Drought in Others
The United States provides a useful example. During El Niño years, the southern part of the country often experiences increased rainfall as the jet stream shifts southward. That can raise the risk of flooding along rivers and in urban areas.
At the same time, increased precipitation can provide welcome relief to drought-stricken regions by replenishing reservoirs and groundwater. The western and northern parts of the country can experience a very different pattern, with warmer and drier conditions in some areas.
California illustrates the uncertainty particularly well. The state experienced historic flooding during the 1997–98 El Niño, yet conditions were much drier than average during the 2015–16 event. That is an important lesson: El Niño loads the climate dice, but it does not determine every roll. Natural variability still matters.
The Pacific Is Churning
El Niño also has consequences for tropical storms and hurricanes. In the Pacific, warmer waters can help provide the energy needed for storms to intensify. In the Atlantic, El Niño can have the opposite influence by increasing atmospheric conditions that make hurricane development more difficult.
That means one side of the planet can experience a more active storm season while another sees reduced hurricane activity. Again, there is no single “El Niño weather.” There are many regional responses to the same global climate phenomenon.
But warmer ocean temperatures can make some storms more dangerous by providing additional heat and moisture to the atmosphere. The Pacific, therefore, becomes another place where the interaction between ocean temperature and atmospheric circulation can reveal the power of El Niño.
Nature Is Keeping the Record
We often describe climate change through numbers. Degrees of warming. Tonnes of carbon dioxide. Millimetres of sea-level rise. But nature keeps its own records. A coral reef loses its colour. A fish disappears from familiar waters. A marine heatwave lasts another month. A coastal community experiences flooding more frequently. A species moves hundreds of kilometres toward cooler seas.
A storm draws energy from unusually warm water. These are the living records of a changing planet. The latest ocean-temperature record is simply another entry.
The Ocean Is Telling Us Something
For generations, the sea has absorbed our excess heat almost silently. It has taken the burden of our emissions and hidden much of their immediate impact beneath its surface. But the ocean is not an infinite sink. It is a living system. And now the signs of stress are becoming increasingly difficult to ignore.
The world’s oceans have reached extraordinary temperatures at a time of year when they would normally be cooling. At the same time, a powerful El Niño is developing on top of decades of human-caused warming. That is why this story matters. It is not merely about a fraction of a degree.
It is about the direction in which the entire Earth system is moving. The ocean is warming. El Niño is adding another pulse of heat. Marine ecosystems are under increasing pressure. Weather patterns are becoming more volatile. And the future of the planet is being written beneath the waves.
