NASA satellites show El Niño raising Pacific sea level by as much as 40 centimeters in places
NOAA puts the odds at 83% that the strongest El Niño since 1950 is under way, NASA reports. Satellite maps show the Pacific warming and sea level shifting.
The Scientist · Science desk
Key figures: sea level is at least 15 cm, up to 20 cm, below normal around Indonesia and northern Australia; warm water has raised local sea level in some areas by as much as 30 to 40 cm; eastern Pacific sea surface is about 1.7 C (about 3 F) above the long-term average, per Josh Willis.
| Figure | Value | Note | Claim |
|---|---|---|---|
| Sea level below normal, Indonesia and N. Australia | 15 cm, at least | up to 20 cm | 6 |
| Peak local sea level rise from warm water | 30 cm, at least | as much as 30 to 40 cm in some areas | 5 |
| Eastern Pacific sea surface, above long-term average | 1.7 °C, about | about 3 F, per Josh Willis | 9 |
What happened
- A swell of warm water called a Kelvin wave first showed up in satellite imagery near Micronesia, in the western Pacific, in January 2026.
- By early April those waves had reached the eastern Pacific, and sea surface temperatures there had begun to warm.
- Eastern Pacific surface water is now about 1.7 C (3 F) above the long-term average, and NASA's Josh Willis said it could rise another fraction of a degree in the coming months.
- On the other side of the basin, sea level sits 15 to 20 centimeters below normal around Indonesia and northern Australia.
- NASA's PACE satellite team reports that equatorial Pacific water has become measurably bluer over the last several months.
Why it matters
- What it limits constraint On NASA's wording, the other 17% covers an El Niño that falls short of the strongest since 1950, so any plan built on the 83% case carries that remainder.
- Who's exposed exposure The raised water was seen heading toward South America and then up the coast to California, so shorelines along that route are where the added height lands.
- What's now possible capability Microwave and infrared radiometers see through and around clouds, so satellites could map the warm band as it expanded through the spring.
NASA describes the start of an El Niño as a chain reaction. A Kelvin wave carries warm water west to east across the Pacific [12]. The warm water heats the air above it, and the air rises [12]. The change in pressure weakens or even reverses the trade winds, so eastern Pacific sea levels rise further and the water warms more [12].
"Kelvin waves are like the heartbeat of El Niño," said Josh Willis, who serves as project scientist on NASA's sea-level missions at JPL in Southern California. "And our sea level satellites let us peer into the ocean and watch every beat." [7]
The height record behind those maps is long. Scientists have tracked ocean height by satellite altimetry since 1993, the record continues with the Sentinel-6 satellites, and their radar altimeters survey millions of square miles of ocean in a single day [8]. They work alongside NOAA's fleet of buoys and other sensors in the water [8]. Warm water expands in volume, so some of the height the altimeters register is heat [5].
The thing the satellite maps don't tell you is where this event ranks. In our view they confirm a warming event under way, and the "strongest since 1950" label rests on NOAA's forecast. NASA says farmers, firefighters and coastal communities are already experiencing the effects in different ways [16], but the page relays NOAA's 83% second-hand, does not name the index behind "strongest", and leaves those effects unitemized [2].
The comparison set is also small. NASA says El Niño emerges roughly every two to seven years [1]. Over the 76 years from 1950 to 2026, that implies roughly 11 to 38 events to rank against [15].
What to watch
- NOAA's next El Niño outlook: whether the 83% figure moves, and which strength index it is tied to.
- Whether eastern Pacific surface temperatures climb the further fraction of a degree Willis said was possible in the coming months.
- Whether the sea-level pattern holds, with water high toward the Americas and low around Indonesia and northern Australia, as the event matures.
Clarity's read
What the record supports and how the coverage leans. The claims behind it follow.
Reality
- Evidence58
- Adoption
- Insufficient
- Hype gap+15
- Incentives
- Insufficient
- Confidence45
Claim ledger
Ranked by verification strength, evidence, and original report placement.
- [1]
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.
- [2]
As of October, NOAA has said there is an 83% chance that the strongest El Niño since 1950 is currently unfolding.
- [3]
One of the first clues appeared in satellite imagery in January 2026, when a swell of warm water called a Kelvin wave was spotted near Micronesia in the western Pacific.
- [4]
By early April, the Kelvin waves had reached the eastern Pacific, and sea surface temperatures had begun to warm.
- [5]
Warm water expands in volume, elevating local sea levels in some areas by as much as 1 to 1.3 feet (30 to 40 centimeters).
- [6]
Sea levels that are six to eight inches (15 to 20 centimeters) lower than normal are visible around Indonesia and northern Australia.
- [7]
"Kelvin waves are like the heartbeat of El Niño," said Josh Willis, project scientist for sea level missions at NASA's Jet Propulsion Laboratory in Southern California. "And our sea level satellites let us peer into the ocean and watch every beat."
- [8]
Scientists have used satellite altimetry to track ocean height since 1993; the record continues with the Sentinel-6 satellites, whose radar altimeters survey millions of square miles of ocean in a single day, complementing NOAA's fleet of ocean sensors and buoys.
- [9]
Sea surface temperatures in the eastern Pacific are about 3 degrees Fahrenheit (1.7 degrees Celsius) warmer than the long-term average and could jump another fraction of a degree in the coming months, Willis said.
- [10]
Satellites carrying microwave and infrared radiometers can see through and around clouds to measure heat energy at the sea surface, and in 2026 they mapped the band of warmer-than-normal water as it expanded throughout the spring.
- [11]
A NASA satellite is tracking subtle shifts in ocean color, as equatorial Pacific waters have become measurably more blue over the last several months.
- [12]
Kelvin waves transfer heat from west to east across the Pacific; the warm water heats the air above it, making it rise; the change in air pressure weakens or even reverses the trade winds, causing sea levels in the eastern Pacific to rise further and waters to warm even more, which signifies the start of an El Niño.
- [13]
The higher-than-normal water can be seen sloshing toward South America and then moving up the coast to California.
- [14]
On NASA's wording of the NOAA figure, the remaining probability is 17%.
- [15]
If El Niño emerges every two to seven years, the 76 years from 1950 to 2026 would hold roughly 11 to 38 events.
- [16]
People around the world, including farmers, firefighters and coastal communities, are already experiencing the effects of El Niño in different ways.
Get this ledger inside ChatGPT. Ask about any of our stories and the answer brings its figure, each claim’s verdict and the sources. Free, no account.
Sources
1 independent publisher whose own reporting we read for this story.
- nasa.govNASA Satellites Observe Historic 2026 El Niño
1 article · October 15, 2026
Topics and entities
Follow any of these and your For You feed starts watching them — no settings page required.