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The world is warming despite natural fluctuations from the El Niño cycle

Veronika Samborska

In 2025, the world was around 1.4 °C warmer than it was in pre-industrial times. But temperatures haven’t increased linearly; there have been spikes and dips along the way.

Many of these spikes and dips are caused by the El Niño-Southern Oscillation (ENSO), a natural climate cycle caused by changes in wind patterns and sea surface temperatures in the Pacific Ocean that affects global temperatures and climate.

There are two key phases of the ENSO cycle: La Niña, which causes cooler global temperatures, and El Niño, which brings warmer conditions.

The world cycles between El Niño and La Niña phases every two to seven years. There are also “neutral” periods between these phases where the world is not in either extreme.

As you can see in the chart, global temperatures during recent La Niña years were hotter than El Niño years just a few decades before. “Cool” years today are hotter than “warm” years not too long ago.

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Line chart of monthly global average land–sea surface temperature anomalies relative to the 1991 to 2020 average, where the series from January 1950 to March 2026 shows a clear upward trend and recent "cool" (La Niña) periods are still warmer than many past "warm" (El Niño) peaks. The chart specifically highlights that this year's La Niña phase is hotter than the warm El Niño phase in 2007 and shows neutral periods between phases. Data source: Copernicus Climate Change Service (2026), NOAA (2026). License: CC BY.