New coral evidence shows El Niño has grown 36 percent stronger since the industrial age began. Here is how the pattern works, why warming is amplifying it, and what a supercharged El Niño means for weather, food, and economies worldwide.
In the tropical Pacific right now, a wall of warm water several degrees above normal is spreading across an ocean surface roughly the size of the continental United States. Forecasters at NOAA say there is a better than 90 percent chance it becomes a “very strong” El Niño before winter, and some model runs suggest it could end up the most intense event on record. That alone would be a notable weather story. What makes it more than that is a study published this week in the journal Science, built from coral skeletons that have been quietly recording ocean temperature for a thousand years, showing that El Niño itself has changed. Today’s El Niño events are, on average, more than a third stronger than they were before humans started burning fossil fuels at scale, and most of that increase has piled up in just the last four decades.
That finding reframes the current Pacific warm up. It is not only a single unusually large event. It is a data point on a rising curve, one that scientists had suspected for years but could not previously prove because reliable ocean temperature records only stretch back about 75 years, too short a window to separate a real trend from natural noise. The new research fixes that problem by reading a much longer archive, and in doing so it turns a seasonal weather story into something with lasting relevance for how farmers plan harvests, how insurers price risk, and how households everywhere experience heat, drought, and flooding in the years ahead.
What the New Coral Study Actually Found
El Niño and its cooler counterpart, La Niña, are phases of a single ocean and atmosphere cycle called the El Niño Southern Oscillation, or ENSO. Reconstructing how that cycle behaved before satellites and ocean buoys existed requires a proxy, a physical record that changes in a measurable way as temperature changes. Coral skeletons are one of the best proxies available. As a coral colony grows, it lays down new skeletal material year after year in a way that mirrors tree rings, and the ratio of certain trace elements it absorbs from seawater, along with the ratio of oxygen isotopes it incorporates, shifts with the temperature of the water around it at the time. Drill a core through a living coral, or through a fossil coral skeleton that died centuries ago but stayed intact on the seafloor, and you get a chemical diary of sea surface temperature that can run back hundreds or thousands of years.
The research team, whose findings were reported this week by the Associated Press, assembled coral records stretching back roughly a thousand years from sites across the tropical Pacific where the ENSO signal is strongest. According to reporting on the study in Scientific American, the swings in ocean temperature associated with ENSO were relatively modest and stable through most of that thousand year window, began climbing gradually in the late nineteenth century, and then jumped sharply over the last forty to fifty years. When the team compared the observed changes against climate model simulations of a world without industrial greenhouse gas emissions, the recent amplification was larger than anything the models produced from natural variability alone.
The headline numbers are stark. El Niño events today are calculated to be more than 36 percent stronger than they were before the mid 1800s, and 16 percentage points of that increase have arrived in just the last forty years, according to the Associated Press summary of the Science paper. That acceleration is the part that should catch attention. A slow, steady increase over a century would be one story. A trend that is compounding within living memory is a different one, because it means the El Niño events people are living through now are meaningfully more extreme than the ones their parents experienced at the same stage of life, and the gap is widening rather than leveling off.
One of the study’s researchers, oceanographer Julia Cole, described the pattern to AFP as parallel to global warming itself, suggesting the strengthening is tied to the same fossil fuel driven warming that is raising average planetary temperature. Climate scientist Andrew Dessler of Texas A&M University, who was not involved in the work, told AFP the findings reinforce the case for shifting away from fossil fuels toward renewable energy, framing the coral evidence as one more line of proof connecting emissions to the specific, tangible extremes people experience, rather than only to a slowly rising average.
The Ocean and Atmosphere Machine Behind Every El Niño
To understand why a warmer planet would make El Niño worse, it helps to understand what El Niño actually is mechanically, rather than just as a label attached to bad weather.
Under normal conditions, trade winds blow steadily from east to west across the tropical Pacific, dragging warm surface water toward Asia and Australia and piling it up there, while allowing cooler water to well up from the deep ocean off the coast of South America. This lopsided arrangement, warm water in the west, cool water in the east, drives a giant loop of rising and sinking air called the Walker Circulation, which in turn shapes rainfall patterns across a huge swath of the planet.
El Niño happens when that arrangement breaks down. The trade winds weaken or even reverse, the warm water that had been stacked up in the western Pacific sloshes back eastward, and the cool upwelling off South America shuts off. NOAA’s Climate Prediction Center defines an El Niño as a period when sea surface temperatures in a monitored strip of the central Pacific, called the Nino 3.4 region, run at least 0.5 degrees Celsius above the long term average for several consecutive months, as described in NOAA’s official advisory. Anything above roughly 2.0 degrees Celsius above average is classified as a very strong event, a threshold NOAA’s Climate Prediction Center currently gives greater than 90 percent odds of being crossed this fall and winter, according to its most recent ENSO diagnostic discussion.
Because the tropical Pacific covers such a large share of Earth’s surface, shifting where its heat goes reshapes the jet stream, redirects storm tracks, and reorganizes rainfall on nearly every continent. That is why a warm patch of ocean thousands of miles from land can mean drought in southern Africa, flooding in Peru, a milder winter in the northern United States, and a suppressed hurricane season in the Atlantic, all from the same underlying cause. It also explains why El Niño’s strength matters so much. A mild event nudges these patterns. A very strong event can override them.
Why a Warmer Ocean Would Push El Niño Toward Extremes
Scientists have theorized for decades that global warming should intensify ENSO swings, for a fairly intuitive reason: El Niño’s strength is fundamentally a measure of a temperature difference across the Pacific, and processes that widen temperature differences tend to widen the resulting swings. The trouble was proving it. Direct instrumental records of ocean temperature only go back to the mid twentieth century in any reliable, widespread form, which is not a long enough window to distinguish a genuine trend from the ordinary up and down chatter of a system that varies naturally from year to year and decade to decade.
The mechanism researchers point to most often is a change in ocean layering known as stratification. As the sea surface absorbs more heat from a warming atmosphere, the thin top layer of the ocean warms faster than the deeper water beneath it, according to reporting on the new study in Scientific American. That creates a sharper boundary, or thermocline, between the warm surface layer and the cooler water below. A sharper thermocline means that when winds or currents do pull deep water up toward the surface, as happens constantly in the eastern Pacific, the contrast between that upwelled water and the surrounding surface water is bigger than it used to be. The ocean essentially becomes more responsive, swinging further in both directions when the usual triggers occur. The researchers behind this study are careful to note that the exact chain of cause and effect is still being refined, and that stratification is one leading explanation rather than a fully settled one.
This is a useful moment to separate what is confirmed from what is still analysis. That El Niño events have grown stronger over the industrial era, and that the increase exceeds what natural variability alone would produce in climate model simulations, is what the coral record and the accompanying model comparisons in the new Science study establish. That ocean stratification is the specific physical mechanism responsible is a leading scientific explanation supported by other modeling work, but it remains an active area of research rather than a fully closed case. Readers should treat the first claim as well supported and the second as a strong, evidence backed hypothesis still being tested.
A History of Escalating Events, From 1982 to 2026
Long before scientists had coral evidence of a centuries long trend, they had a shorter but still telling record of individual El Niño events getting more dramatic. The 1982 to 1983 event surprised forecasters with its intensity and reshaped how seriously the phenomenon was studied. The 1997 to 1998 El Niño, still one of the most closely analyzed in history, triggered droughts across Indonesia and the Amazon, flooding across the southern United States and Peru, and widespread coral bleaching, and was linked by researchers to tens of billions of dollars in global damage and disruption to agriculture and fisheries.
The 2015 to 2016 event pushed global average temperatures to what was then a record high and contributed to a severe, multi year drought across parts of southern Africa that left millions of people dependent on food aid. The 2023 to 2024 El Niño arrived on top of decades of additional background warming and helped drive 2023 and 2024 into the record books as the two warmest years measured up to that point, illustrating a metaphor NOAA scientists have used repeatedly: El Niño rides on top of the steady, human caused warming trend the way a person walking up an escalator moves faster than the escalator alone, a comparison laid out clearly by CNN’s climate coverage of the current event. Each step up is a natural swing of the ENSO cycle. The escalator itself, moving steadily upward regardless of which step you are on, is the long term warming trend.
The event now forming fits that pattern and then some. Weekly Nino 3.4 readings had already reached roughly 2.7 degrees Celsius above average by mid August, according to tracking from Columbia University’s International Research Institute for Climate and Society, comfortably inside very strong territory and still climbing. Separate analysis from AccuWeather notes that if the forecast three month average verifies, it would exceed the previous record set during the 1982 to 1983 winter, making this potentially the strongest El Niño ever measured using modern instruments.
What a Very Strong El Niño Does to Weather, Food, and the Ocean Itself
The practical consequences of El Niño strength are not abstract. They show up in specific, measurable ways across very different systems.
On hurricanes, a strong El Niño tends to increase wind shear across the Atlantic basin, which tears apart developing tropical storms before they can organize. AccuWeather’s seasonal outlook, cited above, lowered its named storm forecast for the 2026 Atlantic season specifically because of the strengthening El Niño, while still warning that unusually warm coastal water can allow storms that do form to intensify quickly close to shore, a reminder that a suppressed storm count does not automatically mean a safe season.
On global temperature, El Niño releases heat that has been stored in the ocean back into the atmosphere, which is why El Niño years so often coincide with record breaking global average temperatures. Carbon Brief’s mid year climate assessment found that the odds of 2026 setting a new global temperature record had nearly doubled within a few months, rising to roughly 35 percent, almost entirely because of the rapidly intensifying El Niño, according to its state of the climate report. Separately, CNN’s reporting notes that meteorologists now consider it virtually certain that the year following the event’s peak will set a new global heat record, based on how past strong El Niños have played out.
On sea level, ocean research published this year found that the two most recent strong El Niño events, in 2014 to 2016 and 2023 to 2024, each produced a temporary but measurable jump in global mean sea level, driven mainly by shifts in how much water is stored on land versus in the ocean, according to findings summarized by Phys.org. A stronger El Niño, by this logic, would be expected to produce a correspondingly larger, if temporary, sea level bump, adding short term stress to coastal areas already dealing with the slower steady rise driven by melting ice sheets and warming ocean water.
On agriculture and food security, the pattern from past strong events is consistent even if outcomes vary by region. Rainfall that shifts away from its normal pattern tends to hit some of the same geographies repeatedly, including drought risk in southern Africa, Indonesia, and parts of Australia, and flood risk along the Pacific coast of South America. Because El Niño’s rainfall effects are broadly predictable months in advance, even if their exact magnitude is not, agricultural ministries and aid organizations in vulnerable regions use ENSO forecasts as an early warning system, prepositioning food reserves and adjusting planting advice ahead of a forecast strong event rather than reacting after a harvest has already failed.
How Scientists Turned a Coral Reef Into a Thousand Year Thermometer
It is worth pausing on how unusual it is that a marine invertebrate provides some of the best evidence available for a climate trend. Corals build their skeletons from calcium carbonate drawn out of seawater, and the precise chemistry of that skeleton depends partly on water temperature at the moment each layer formed. By slicing a coral core into thin sections corresponding to specific time periods, researchers can measure the ratio of strontium to calcium and the ratio of oxygen isotopes in each section and convert those ratios into an estimated sea surface temperature for that period, sometimes down to monthly resolution.
This method has been validated by comparing coral based temperature estimates from recent decades against actual satellite and buoy measurements from the same period and location. Earlier work led by researchers including Kim Cobb at the Georgia Institute of Technology, published in 2019 in the journal Geophysical Research Letters, found that coral records from 1981 to 2015 tracked satellite sea surface temperature measurements closely enough that the two data sets essentially overlapped on a graph, according to a summary from Georgia Tech’s Ocean Science and Engineering program. That 2019 study, working with roughly 7,000 years of coral evidence, found industrial age ENSO swings to be about 25 percent stronger than the pre-industrial baseline, an early version of the same conclusion the new Science study extends and sharpens with a broader data set and a somewhat higher estimate.
This kind of paleoclimate reconstruction matters well beyond El Niño specifically. Tree rings, ice cores, lake sediments, and coral skeletons together form what scientists call proxy records, and they are the primary tool for understanding how Earth’s climate behaved before humans started measuring it directly. Whenever a study claims a modern climate extreme is unprecedented, a proxy record spanning centuries or millennia is usually the evidence doing the heavy lifting, because it is the only way to know what “normal” actually looked like before recent memory.
Separating What Is Settled From What Is Still Uncertain
Not every question about El Niño’s future is answered by the new coral evidence, and it is worth being direct about where the remaining uncertainty sits.
Climate models themselves disagree about the future. Research published in the journal Climate Dynamics and summarized in a peer reviewed article available through the National Center for Biotechnology Information notes that most climate models participating in the current generation of international model comparisons project a continued increase in ENSO variability under future warming, but a smaller subset of models that better match observed twentieth century Pacific temperature trends instead project a shift toward conditions that could eventually weaken El Niño’s amplitude rather than strengthen it further. In plain terms, scientists are confident El Niño has already gotten stronger. They are considerably less certain about whether that trend will keep climbing in a straight line, plateau, or eventually reverse, because it depends on aspects of Pacific Ocean circulation that current models do not yet simulate with full confidence.
It is also worth being clear that not every extreme weather event during an El Niño year is directly caused by El Niño. El Niño shifts the odds of certain patterns in certain regions. It does not single handedly generate every drought, flood, or heat wave that occurs somewhere on the planet during its active phase. Attributing a specific storm or a specific harvest failure entirely to El Niño, rather than to a mix of El Niño, other regional weather drivers, and background climate change, oversimplifies a more layered picture, and forecasters and news coverage sometimes blur that distinction under deadline pressure.
What This Means for Businesses, Farmers, and Households Planning Ahead
For anyone whose work or household budget is sensitive to weather, an El Niño forecast is not just a curiosity, it is planning information, and a body of evidence showing El Niño itself is trending stronger changes how much weight that planning information should carry.
Agricultural producers in regions with well documented El Niño sensitivity, including parts of Australia, Indonesia, southern Africa, and the western coast of South America, can treat a strong El Niño forecast as a cue to reassess planting timing, crop selection, and water storage months before the growing season is underway, rather than waiting for a drought or flood to become visible in the field.
Insurers and reinsurers that price weather related risk, particularly crop insurance and flood insurance in ENSO sensitive regions, have long incorporated ENSO forecasts into their models. Evidence that the underlying phenomenon is intensifying over time is the kind of structural shift that actuaries need to feed back into long run risk models, rather than treating recent strong events as unusual outliers likely to revert toward historical averages.
Coastal planners and infrastructure managers can use the sea level research described above as a concrete, near term planning input, since a strong El Niño’s temporary sea level boost can compound with high tides and storm surge to produce flooding in low lying coastal areas even without a hurricane making landfall nearby.
For most individual households, the more immediate takeaway is less about El Niño specifically and more about what it represents, a demonstration that natural climate variability and human driven warming do not operate as separate, additive forces. They interact, and in this case the interaction appears to be amplifying, which is a reason to take seasonal extreme weather outlooks from national weather agencies more seriously in a strong El Niño year than in an average one.
Could Stronger El Niños Become the New Normal, or Is a Correction Coming
Whether the trend documented in this week’s study continues depends on questions researchers are still actively working through, most centrally on how the balance between surface warming and deep ocean warming evolves as the planet continues to heat up. If surface waters keep warming faster than the deep ocean, the stratification mechanism researchers point to would be expected to keep intensifying ENSO swings. If deep ocean warming eventually catches up, or if large scale Pacific circulation patterns shift in ways current models do not fully anticipate, the amplification could level off or even partially reverse, as the more skeptical subset of climate models cited above suggests is possible.
What is not in serious scientific dispute is the direction of travel over the past several decades. The coral record gives researchers, for the first time, a long enough baseline to say with real confidence that the El Niño events of the last forty to fifty years fall outside anything the Pacific produced naturally over the previous thousand years. That is a different kind of claim than a forecast about next decade’s ENSO behavior, and it is the one this week’s Science study establishes most firmly.
The Pacific Is Rewriting Its Own Rulebook, and the Record Books Are Next
The 2026 El Niño now intensifying in the Pacific will eventually peak, fade, and give way to a cooler phase, as every El Niño before it has. What the new coral evidence changes is the context in which that cycle gets read. For most of the modern instrumental era, unusually strong El Niño events were treated as high end outliers within an otherwise stable natural cycle, dramatic but fundamentally normal. A thousand year temperature record pulled from coral skeletons complicates that framing. It suggests the cycle itself has been recalibrated by the same warming driving other well known climate shifts, and that recalibration has been happening quietly, underneath individual weather headlines, for decades.
The immediate story is a very strong El Niño shaping this winter’s storms, droughts, and global temperature records. The longer story, the one likely to matter well after this particular event fades from the news, is that the baseline itself is moving, and the tools scientists use to notice that kind of gradual, compounding shift, whether coral cores, tree rings, or ice sheets, are becoming some of the most consequential instruments in climate science precisely because they can see further back than any thermometer.
