Is El Niño Getting Worse? Climate Change and the Future of ENSO

Published: July 7, 2026 · 8 min read

What the Models Say

CMIP6 — the latest generation of global climate models — produces conflicting answers on ENSO's future. Some models project more frequent El Niño. Some project less. Some project no change. The disagreement reflects genuine scientific uncertainty about how the tropical Pacific's delicate ocean-atmosphere balance will respond to greenhouse forcing.

But zoom in on the strongest events, and the picture sharpens. A series of papers led by Wenju Cai (CSIRO, published in Nature Climate Change and Nature) has found that the frequency of "extreme" El Niño events (ONI > +2.0 °C) could double under high-emissions scenarios — from roughly one per 20 years to one per 10 years by 2100. The mechanism: faster warming in the eastern equatorial Pacific, which reduces the temperature gradient that normally keeps the warm pool in the west. A reduced gradient makes it easier for El Niño to develop and intensify.

The Amplification Effect: Why Even "Normal" El Niños Hit Harder

This is the part where the science is more settled. Even if ENSO itself doesn't change — same frequency, same amplitude — a warmer world means El Niño impacts are worse. A warmer atmosphere holds more moisture (Clausius-Clapeyron: ~7% per °C). So the rainfall extremes that El Niño produces — floods in Peru, California, East Africa — get heavier. The drought regions — Australia, Indonesia, India — get drier because warmer air evaporates more moisture from soils.

And the baseline temperature is higher. The 1997-98 El Niño happened in a world that was about +0.5 °C above pre-industrial. The 2026-27 event is unfolding at about +1.3 °C. That extra 0.8 °C of background warming means the temperature anomalies during this El Niño start from a higher floor. Heat extremes that were once rare become common. Marine heatwaves that bleach coral are more likely because the ocean starts warmer.

The Observational Record: What We've Actually Seen

Since 1950, we have reliable ENSO observations. The record shows no clear trend in El Niño frequency — about 22 El Niño events in 76 years, or roughly one every 3-4 years with no obvious acceleration. The amplitude record is more suggestive: four of the six strongest events (by ONI) have occurred since 1982 (1982-83, 1997-98, 2015-16, 2023-24). But with only 76 years of data and strong natural variability, it's not possible to formally distinguish a climate change signal from random clustering.

The next 20-30 years of observations will be critical. If the 2020s, 2030s, and 2040s continue to produce a disproportionate share of strong events, the detection threshold will be crossed. The 2026-27 event is another data point in that statistical test.

What Does This Mean for the Future?

The precautionary read: plan for stronger El Niño impacts than the historical record would suggest. Even if ENSO itself doesn't change, the world it operates in has. The combination of higher baseline temperatures, more atmospheric moisture, and more people living in vulnerable regions means that a +2.0 °C El Niño in 2026 does more damage than a +2.0 °C El Niño in 1982. That's not a model projection — it's observable fact. The 2026-27 event will be the latest evidence.

Why This Matters: From Physics to Food Prices

Understanding is el niño getting worse isn't just an academic exercise — it's the foundation for predicting droughts, preparing for floods, and stabilizing food systems across the tropics. Every El Niño forecast, every crop insurance contract, every reservoir management decision traces back to the physical processes described on this page.

The chain of consequences runs deep. Changes in Pacific Ocean temperature gradients shift atmospheric convection patterns, which redirect the jet streams, which alter storm tracks, which determine whether a farmer in Brazil gets rain or drought during the critical soybean flowering period. That single farmer's outcome — multiplied across millions of hectares — shows up in global commodity prices, shipping volumes, and ultimately your grocery bill.

In short: is el niño getting worse is a lever that moves the world. The better we understand it, the better we can prepare for what it does next.

Explore more at the El Niño Guide — comprehensive climate science explained.