NASA satellites track strongest El Niño since 1950

NASA said its satellites are tracking the strongest El Niño since 1950. The agency reported that as of October, the National Oceanic and Atmospheric Administration said there is an 83% chance this powerful climate pattern is currently unfolding. El Niño is a natural climate pattern that emerges roughly every two to seven years marked by warmer-than-normal water temperatures in parts of the equatorial Pacific.

Scientists first detected initial signs in satellite imagery in January 2026, when a Kelvin wave appeared near Micronesia in the western Pacific. These slow-moving pulses of warm water transfer heat from west to east across the Pacific. By early April, those waves had reached the eastern Pacific and sea surface temperatures had begun to warm. The warm water heats the air directly above it, causing it to rise. The change in air pressures weakens or reverses the trade winds, which normally blow from the Americas toward Asia.

The warming has raised sea levels in parts of the eastern Pacific by 1 to 1.3 feet. Waters around Indonesia and northern Australia are 6 to 8 inches below normal. Sea surface temperatures in the eastern Pacific are about 3 degrees Fahrenheit warmer than the long-term average. The warm water expands in volume, elevating local sea levels in some areas. The higher-than-normal water can be seen sloshing toward South America then moving up the coast to California.

NASA scientists are using Sentinel-6 satellites to measure sea surface height with ultraprecision. The agency has used satellite altimetry to track the height of the ocean since 1993. The PACE satellite, launched in 2024, is monitoring changes in ocean color. Equatorial Pacific waters have become measurably more blue, indicating a decline in phytoplankton. Phytoplankton thrive in cool, nutrient-rich waters. During El Niño, the weakening trade winds reduce the upwelling of nutrient-rich deep water to the ocean surface. With limited food supply, phytoplankton abundance drops.

The agency said effects are being experienced by farmers, firefighters and coastal communities around the world. Josh Willis, project scientist for sea level missions at NASA's Jet Propulsion Laboratory, said Kelvin waves are like the heartbeat of El Niño. NASA scientists will continue monitoring this El Niño with their fleet of Earth-observing satellites.