A powerful El Niño event is rapidly developing in the Pacific Ocean, with new satellite observations from NASA showing a large build-up of heat beneath the sea surface. Data from the Sentinel-6 Michael Freilich satellite indicates unusually high sea levels across the equatorial Pacific, especially in the central and eastern regions, along with a broad area of elevated levels near the coast of South America. Scientists interpret these higher sea levels as a sign of significant heat accumulation below the ocean surface, since warmer water expands and raises sea level.
Unlike surface temperature readings alone, sea surface height measurements help reveal how much thermal energy is stored in the upper layers of the ocean. According to researchers at NASA’s Jet Propulsion Laboratory, the current conditions in parts of the western Pacific are increasingly similar to those seen in June 1997, when one of the strongest El Niño events on record began to develop, later associated with severe global weather disruptions.
That 1997–98 episode, sometimes referred to as a “Godzilla El Niño,” was linked to extreme floods, droughts, agricultural losses, and heatwaves across multiple regions of the world. Scientists now say the present system is strengthening and could evolve into a major climate event if current trends continue.
The US National Oceanic and Atmospheric Administration (NOAA) had already declared El Niño conditions on June 11 after several months of above-average sea surface temperatures in the central and eastern Pacific. The latest satellite data from early June shows extensive regions of higher-than-normal sea levels, suggesting that a large pool of warm water is expanding eastward across the ocean basin.
This movement of heat is being driven by Kelvin waves—large underwater waves that can span hundreds of kilometres. These waves form when Pacific trade winds weaken or reverse, allowing warm water that usually accumulates near Indonesia and Australia to shift toward the Americas. This process reduces the upwelling of cold, nutrient-rich water off South America and contributes to rapid ocean warming in the eastern Pacific, which is a defining feature of El Niño conditions.
Scientists note that while the eastern Pacific has not yet reached the extreme warming levels seen in 1997, additional Kelvin waves are already moving into the region, indicating that the event is still intensifying. If it continues to strengthen, the developing El Niño could have widespread global impacts, typically bringing heavier rainfall to parts of the Americas while increasing the risk of drought in regions such as Australia, Indonesia, and parts of Asia.
