NASA: Sea level rose due to El Niño and climate change – 03/22/2024 – Environment

The global average sea level rose by around 0.76 cm between 2022 and 2023, almost four times more than between 2021 and 2022, NASA said this Thursday (21), attributing the “significant jump” to the El phenomenon. Niño and a warmer climate.

The United States space agency’s analysis is based on more than 30 years of satellite observations, beginning with the first launch of a satellite focused on the subject, in 1992.

“Current rates of acceleration mean we are on track to add another 20 cm to global mean sea level by 2050,” said Nadya Vinogradova Shiffer, director of NASA’s sea level change team and ocean physics program in Washington. .

That would represent double the changes over the next three decades compared to the previous century, he pointed out, which will make floods much more frequent and catastrophic than they are today.

The immediate cause of the increase is the climate phenomenon El Niño, which replaced La Niña between 2021 and 2022, when sea levels rose by around 0.20 cm.

El Niño generates warmer-than-average ocean temperatures in the equatorial Pacific.

“In El Niño years, much of the rain that normally falls on land ends up in the ocean, which temporarily raises sea levels,” explained Josh Willis, a researcher at NASA’s Jet Propulsion Laboratory (JPL).

But there is also a clear human footprint in the underlying accelerating trend.

“Long-term data sets, like this 30-year satellite record, allow us to differentiate short-term effects on sea level, like El Niño, from trends that tell us where sea level is going. ” said Ben Hamlington, NASA marine program leader.

Technological innovations have brought greater precision to measurements.

For example, radar altimeters bounce microwaves off the sea surface and then record the time it takes for the signal to return to the satellite, as well as the strength of the returning signal.

They also check their data with other sources, such as tide gauges and satellite measurements of atmospheric water vapor and the Earth’s gravitational field.