Scientists have identified an ominous sign that a 'super' El Niño is drawing closer. El Niño years are part of the natural El Niño–Southern Oscillation cycle, characterised by sustained warm sea surface temperatures across the Pacific Ocean. When this warming exceeds 2°C (3.6°F), the event is often termed a 'super El Niño'.
Record Sea Surface Temperatures
The Copernicus Climate Change Service has reported that April 2026 recorded the second highest sea surface temperatures ever measured. Daily averages over extra-polar regions approached the record values observed in 2024, suggesting that super El Niño conditions could emerge in the coming months.
Samantha Burgess, Strategic Lead for Climate at the European Centre for Medium-Range Weather Forecasts (ECMWF), stated: 'April 2026 adds to the clear signal of sustained global warmth. Sea surface temperatures were near record levels with widespread marine heatwaves, Arctic sea ice remained well below average, and Europe saw sharp contrasts in temperature and rainfall; all hallmarks of a climate increasingly shaped by extremes.'
Understanding the El Niño Cycle
The El Niño–Southern Oscillation is a natural climate pattern that alternates between a hot El Niño and a cool La Niña phase every two to seven years. During El Niño, warm waters that accumulate in the Pacific spread out, raising the Earth's average surface temperature. This heat eventually escapes into the atmosphere, elevating global temperatures for months. Although this cycle has persisted for hundreds of thousands of years, current indicators suggest that this year could see one of the strongest El Niño patterns ever recorded.
Copernicus data shows that the average sea surface temperature (SST) over 60°S–60°N in April was 21°C (69.8°F). The highest April SST on record occurred in 2024 during the last El Niño event.
Global Temperature Impacts
Beyond sea surface temperatures, April 2026 was the joint third-warmest April globally. Average surface air temperatures reached 14.89°C (58.8°F), which is 0.52°C (0.9°F) above the 1991–2020 average. For reference, the warmest April on record was in 2024, followed by 2025.
The world is currently in a cool La Niña phase, but forecasters have predicted a 62% chance of a switch to El Niño between June and August this year. If a super El Niño develops, it would be only the third such event in the last 30 years.
Climate scientist Zeke Hausfather remarked: 'El Niño is coming, and it is shaping up to be a big one. If a strong El Niño develops, it would push up 2026 global temperatures and particularly 2027 temperatures. 2027 would be increasingly likely to be a record warm year.'
Historical Context
The most recent super El Niño occurred a decade ago, in 2015–2016, and was one of the strongest on record. The phenomenon raises global air temperatures by releasing vast amounts of heat from the tropical Pacific Ocean into the atmosphere. Mr Hausfather explained that the lag between peak El Niño conditions and the global surface temperature response would result in the largest impacts on 2027 temperatures, making that year increasingly likely to set a new record, perhaps by a sizeable margin.
What is the El Niño Phenomenon?
El Niño and La Niña are the warm and cool phases of the El Niño-Southern Oscillation (ENSO), a recurring climate pattern across the tropical Pacific. The pattern shifts irregularly every two to seven years, triggering predictable disruptions in temperature, winds, and precipitation. These changes affect global climate.
- El Niño: A warming of the ocean surface, or above-average sea surface temperatures (SST), in the central and eastern tropical Pacific. Rainfall decreases over Indonesia but increases over the tropical Pacific. Low-level surface winds, which normally blow from east to west, weaken or reverse direction.
- La Niña: A cooling of the ocean surface, or below-average SST, in the central and eastern tropical Pacific. Rainfall increases over Indonesia and decreases over the central Pacific. Normal easterly winds strengthen.
- Neutral: Neither El Niño nor La Niña, with tropical Pacific SSTs generally close to average.
