🌡️ A major climate phenomenon in preparation: record El Niño in 2026?

A water uplift, called a Kelvin wave, is currently progressing in the Pacific along the equator. This signal betrays an intensification of the El Niño phenomenon. Satellite images reveal a band of water higher than average, stretching over hundreds of miles (hundreds of kilometers), resulting from the warming of waters typical of this climatic phenomenon.

This Kelvin wave originates when the westerly winds of the Pacific weaken and temporarily reverse, blowing from west to east instead of east to west. This change allows warm water to gradually accumulate eastward, deepening the warm water layer and preventing cold water from rising from the depths. The Sentinel-6 Michael Freilich satellite detected this wave on June 8, revealing sea level anomalies sometimes reaching more than 6 inches (15 centimeters) above normal.


The satellite, developed by NASA and the European Space Agency, measures variations in sea height with an accuracy of a few millimeters every ten days. This data complements surface temperature observations, which had already indicated a record warming of the Pacific in recent months. On June 11, authorities officially declared the start of a new El Niño, after observing the extent of the anomalies.

Previously, scientists had already observed other Kelvin waves earlier in the year, foreshadowing the arrival of El Niño. In January, a wave near Micronesia dissipated in February, while another, which appeared in March, had already raised sea level off the coast of Peru by May. This last wave has now reached the west coast of South America.

These temperature and sea level changes alter atmospheric circulation and influence weather. El Niño generally increases precipitation in the southwestern United States, Colombia, Peru and Ecuador, while at the same time rainfall decreases in the western Pacific. The previous El Niño, from 2023 to 2024, contributed to making 2024 the hottest year on record, exceeding the 1.5 °C warming limit set by the Paris Agreement.

The current configuration in the western Pacific resembles that of 1997, a year of a particularly strong El Niño. Although the number of Kelvin waves observed in 2026 is lower than in 1997, the episode is still strengthening. Current data suggests it will be a major event, but additional observations are needed to confirm its magnitude.

What is an oceanic Kelvin wave?

A Kelvin wave is a large-scale ocean wave that propagates along the equator or coasts, under the effect of the Earth's rotation. In the equatorial Pacific, these waves travel from west to east, driven by underwater topography and the Coriolis force. They manifest as a rise in sea level and an accumulation of warm water at the surface.

These waves play a key role in triggering El Niño. When trade winds weaken, a Kelvin wave is born and carries eastward the warm water normally accumulated in the western Pacific. Upon reaching the American coast, this warm water prevents cold water from upwelling, which warms the atmosphere and alters precipitation on a global scale.

Kelvin waves are often precursors to El Niño. Their detection by satellite alerts climatologists to the imminence of a warm episode. In 2026, several waves were observed before the official announcement of El Niño, confirming their usefulness for seasonal forecasting.