The Intertwined Dynamic of the Unfolding Super El Niño and Human-Driven Climate Change
For months, the tropical Pacific has been building up surplus ocean heat, as a rare "super" El Niño event gathers strength. This cyclical climate phenomenon, which emerges on average every few years, has already notched a string of consecutive daily heat records, with forecasters warning it will reach unprecedented intensity over the coming winter. Though defined by abnormally warm surface waters in the eastern tropical Pacific, El Niño is far from a localized regional event: its ripple effects reshape weather patterns across every continent.
It is only natural to ask how this recurring climate cycle interacts with the other, slower-burning planetary climate crisis driven by fossil fuel combustion. While it may seem intuitive that a steadily warming planet would automatically produce hotter, more intense El Niño events, “I have far more open questions than definitive conclusions about what we are observing right now,” notes Christopher Callahan, a climate researcher at Indiana University. In short, the causal relationship between long-term global warming and El Niño behavior remains a highly active area of research — and this year’s extreme event could deliver critical new data to fill knowledge gaps.
The excess ocean heat El Niño generates leaks upward to alter global atmospheric circulation, triggering cascading shifts in weather systems worldwide. The pattern works like a set of lined-up dominoes, where a single nudge sets off a chain reaction of outcomes. The massive volume of excess heat currently sitting in the tropical Pacific is far more than a light tap on the atmospheric system: the resulting weather disruptions are projected to be some of the most severe seen in a generation.
The U.S. National Oceanic and Atmospheric Administration (NOAA) forecasts a 100% chance of an extremely strong El Niño persisting through December, and an 80%+ probability of that intensity holding through the end of February. Observational data confirms this event has already broken multiple all-time daily ocean heat records, including a recent peak of 3.4 degrees Celsius above the long-term baseline. NOAA releases its official El Niño severity metrics as a three-month rolling average, and the agency projects the peak heat anomaly will hit 2.7 degrees Celsius above normal across the October–December period (scientists do not rule out the anomaly exceeding 3 degrees Celsius at its peak). If the forecast holds, this event will shatter the previous all-time El Niño record of 2.4 degrees Celsius, set during the historic 1982–1983 event.
How Is Climate Change Shaping El Niño Behavior?
A rapidly growing body of research confirms that anthropogenic climate change is almost certainly already exerting measurable influence on El Niño patterns. Over the past 60 years, we have seen clear rises in both the magnitude and frequency of major El Niño events, explains Francisco Estrada, coordinator of the Climate Change Research Program at the National Autonomous University of Mexico, alongside greater year-to-year variability in the cycle and uneven shifts in how its impacts are distributed across different regions.
Estrada emphasizes that debates framing El Niño as either “completely natural” or “fully caused by climate change” are fundamentally unproductive: the two forces are not mutually exclusive, but constantly interacting. “You cannot separate El Niño from global warming — the two phenomena are inextricably linked,” he states.
Global climate models also broadly project that El Niño events will grow stronger as the planet continues to warm, though Callahan notes many models still struggle to accurately reproduce long-term historical temperature trends in the eastern tropical Pacific, creating some uncertainty around exact projections. Even so, multiple lines of independent evidence point to warming supercharging El Niño activity. “The vast majority of climate models find that El Niño amplitude will rise in a warming climate, and every paleoclimate record we have shows we are currently in a more active El Niño period than any point in the last 1,000 years,” Callahan says.
A peer-reviewed study published in August, which Callahan did not participate in, draws on data extracted from ancient coral samples to deliver exactly that 1,000-year historical snapshot. The research found a clear uptick in El Niño strength that lines up directly with the timeline of widespread human greenhouse gas emissions, even though the authors did not formally complete attribution to confirm climate change as the direct cause. This year’s extreme El Niño will add another critical modern data point to help researchers untangle that causal relationship.
How Does El Niño Amplify Existing Climate Change Impacts?
As Callahan points out, the reverse dynamic is equally important to study: how El Niño layers its impacts on top of decades of accumulated global warming. “Even if climate change had not made this specific El Niño event stronger, even if its sea surface temperature anomalies were 100% natural, the fact that those warm ocean conditions are playing out on a planet already altered by decades of global warming is almost guaranteed to produce unprecedented, unanticipated impacts,” he explains.
El Niño’s well-documented cross-global weather effects, called teleconnections, include heightened drought risk in the Amazon and Indonesia, boosted extreme rainfall across the U.S. Southwest, and suppressed Atlantic hurricane activity. But the overlap with long-term climate change does not just preserve these old patterns: many of these impacts are being amplified far beyond historical levels. “We can no longer place the same level of confidence in past observational data about how El Niño manifests in weather and climate patterns across different parts of the world,” Estrada warns, as the old baselines that those patterns were built on have already shifted.
The Compound Climate Risk of the Two Overlapping Crises
From a risk management perspective, Estrada argues that understanding the two-way interaction between El Niño and long-term warming, and how that compound effect hits human societies, is far more critical than merely tracking whether this event will break all-time intensity records. Both Estrada and Callahan note that their top concern is not the El Niño itself, but the combination of an exceptionally strong natural cycle event unfolding on a planet that has already warmed 1.1 degrees Celsius above pre-industrial levels. “Unpredictable surprises are the last thing you want to deal with when you are actively trying to manage climate risk,” Estrada says.
Callahan’s own research quantifies the massive societal cost of extreme El Niño events: the most severe cycles can drag trillions of dollars in losses off global GDP over their multi-year impact window. Ecosystems also face catastrophic harm, most notably tropical coral reefs, which are currently in the middle of a global mass bleaching event driven by overlapping marine heatwaves.
In response to these overlapping risks, the United Nations and other international bodies have called for urgent, targeted adaptation measures to protect at-risk communities and vulnerable ecosystems. Many local governments have already moved to act pre-emptively: the state of California declared a formal state of emergency related to expected El Niño impacts last month. “El Niño conditions will pour fuel on the fire of a warming world. Impacts will hit even harder, travel even farther, and cross borders with devastating speed,” UN Secretary-General António Guterres noted in a public statement last month.
Additional reporting by Brian Kahn
