Scientists watching the Pacific say a new configuration of sea temperatures is taking shape, one that could steer heatwaves, floods and storms from 2026 onwards. As greenhouse gas levels climb, this natural swing in the climate system is expected to hit harder than in past decades.
From record heat to the next big swing
Climate watchers still talk about 2024 with a mix of disbelief and concern. Global temperatures smashed records month after month. Ocean heat content reached levels that stunned researchers. Two forces sat at the heart of that spike: relentless human‑driven warming and a powerful El Niño brewing in the Pacific.
El Niño is part of the El Niño–Southern Oscillation, or ENSO, a natural seesaw in the tropical Pacific. It has two main phases, often with quiet spells in between:
- El Niño: surface waters in the eastern and central equatorial Pacific become warmer than average
- La Niña: waters in roughly the same region cool below average
From spring 2023 to spring 2024, a strong El Niño poured extra heat into the atmosphere. Years with El Niño tend to be hotter globally than years with La Niña. When that pattern sits on top of long‑term warming from greenhouse gases, the result is a jump in record‑breaking extremes.
ENSO used to be a powerful background rhythm. In a hotter world, it is starting to behave like an amplifier with the volume turned up.
What is changing now in the Pacific
Since mid‑2024, the Pacific has been gradually leaving El Niño behind. Neutral conditions followed, and now models suggest the system is preparing for a different mood from 2026. Several signals are worrying researchers.
Ocean temperatures are not returning to “normal”
During classic ENSO cycles, the eastern Pacific warms during El Niño, then cools during La Niña. Lately, that reset has been incomplete. Baseline sea surface temperatures stay elevated, even in neutral months. The warm‑water background raises the floor for every future event.
That means the next La Niña phase, expected around 2026, will not sit on the same climate as in the 1980s or 1990s. It will unfold in an already overheated ocean–atmosphere system, with more moisture in the air and more stored heat available for extreme events.
Atmospheric circulation is shifting
ENSO does not act alone. It reshapes huge wind patterns: the trade winds, the Walker circulation over the equator, and the jet streams that steer storms mid‑latitude. Observations suggest these large‑scale flows are responding to both ENSO and long‑term warming in new ways.
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Some models hint at more frequent “flips” between strong El Niño and strong La Niña, with shorter neutral pauses. Faster, sharper swings can be more disruptive than slow, gentle oscillations. Farmers, water managers and energy planners have less time to adapt between extremes.
Instead of a gentle pendulum, the Pacific is starting to look like a climate switch that can snap from one extreme to the other.
Why 2026 is a red‑flag year for scientists
Climate prediction centres run ensembles of simulations months to years ahead. Those outlooks converge on a high chance of La Niña conditions emerging or strengthening during 2026. On its own, La Niña tends to cool the global average slightly compared with an El Niño year. In today’s climate, that “cooling” could still leave us near record territory.
| Phase | Typical Pacific signal | Global impact tendency |
|---|---|---|
| El Niño | Warmer eastern/central equatorial Pacific | Higher global temperatures, shifts in rainfall belts |
| Neutral ENSO | Temperatures near long‑term average | Global climate dominated by greenhouse gas trend |
| La Niña | Cooler eastern/central equatorial Pacific | Slightly lower global average, stronger regional extremes |
The concern is not only the global mean. La Niña rearranges where heat and rain concentrate. In a warmer background climate, those rearrangements often mean stronger floods in some regions and longer, harsher droughts in others.
What this could mean for Europe and North America
ENSO events start in the equatorial Pacific, but their fingerprints reach Europe and North America through atmospheric “teleconnections” — chains of cause and effect that bend the jet stream and storm tracks thousands of kilometres away.
Potential knock‑on effects for Europe
For western Europe, including the UK and France, La Niña years have historically been linked to a few tendencies:
- Winters that can flip between mild and stormy spells and brief cold snaps
- Increased chance of heavy rainfall episodes in autumn and winter
- Summers with heightened risk of heatwaves when blocking high‑pressure systems settle in
These links are not fixed rules, but they shape odds. With oceans and land already warmed, a La Niña‑influenced jet stream could drive stronger Atlantic storms, wetter months and episodes of destructive river flooding on top of saturated soils.
North American patterns under a stronger La Niña
Across the Atlantic, La Niña tends to favour more active Atlantic hurricane seasons, as wind shear over the tropical ocean decreases. At the same time, parts of southern North America often face drier winters, while the Pacific Northwest can be stormier and wetter.
In a climate where sea surface temperatures in the Atlantic are also running high, that mix can bring intense land‑falling hurricanes, heavier rain events and greater coastal flood risk. Emergency planners in the US and Caribbean are already factoring this into their medium‑term outlooks.
Regional climate risks are less about a single El Niño or La Niña, and more about how each phase stacks on top of long‑term warming.
How ENSO turbocharges extremes in a warmer climate
The basic physics is straightforward. Warmer air holds more water vapour. Warmer oceans supply that moisture more rapidly. ENSO then decides where the tap opens widest and where it partly shuts.
During a warm‑phase El Niño, heat tends to spread through the atmosphere more evenly, lifting global averages. During La Niña, heat piles up in the western Pacific and adjacent seas, while cooler waters surface in the east. Both situations can intensify local extremes.
Examples from recent decades show the pattern:
- The strong El Niño of 2015–2016 coincided with severe drought in parts of Africa and blistering heatwaves in Asia.
- Multi‑year La Niña episodes from 2020 to 2023 helped load extra moisture into the western Pacific and Indian Ocean, feeding catastrophic flooding in Australia and Pakistan.
The next cycle arriving around 2026 is set against an even higher global temperature baseline. That means the same ENSO strength can now trigger more damaging outcomes than similar events in the past.
Key terms and what they actually mean
Climate discussions often throw around acronyms that sound abstract. A few are central to this Pacific story:
- ENSO: El Niño–Southern Oscillation, the Pacific system that swings between warm (El Niño), cool (La Niña) and neutral phases.
- Sea surface temperature anomaly: the difference between current sea temperature and the long‑term average for that place and time of year.
- Teleconnection: a climate link where changes in one region influence weather patterns far away through the atmosphere.
Understanding these terms helps explain why scientists can look at a patch of warm or cool water in the Pacific and say something meaningful about rainfall odds in Europe months later.
Scenarios for daily life and risk planning
Translated to daily life, a more extreme ENSO cycle from 2026 could show up in several ways. Cities may see more frequent “once in a decade” downpours within a few years. Farmers could face growing seasons that swing wildly between waterlogging and deep soil dryness. Hydropower systems might deal with overloaded dams one year and low reservoirs the next.
Some sectors are already adjusting. Insurance companies are testing stress scenarios for back‑to‑back disaster years fuelled by ENSO on top of long‑term warming. Energy grid operators are modelling heatwave plus drought combinations that limit both cooling capacity and renewable generation.
Planning for the next decade now means planning for a climate that jumps, not just trends.
On an individual level, this doesn’t only point to distant policy debates. It suggests practical questions: Is local flood infrastructure up to a wetter winter? Are building codes coping with hotter, more humid summer nights? Are farmers getting seasonal guidance that includes ENSO‑related risk shifts?
The signals coming from the Pacific hint that such questions will feel less theoretical from 2026 onward, as the climate system enters another charged phase of its natural cycle layered on human‑driven warming.