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NASA Analysis Sees Spike in 2023 Global Sea Level Due to El Niño

A long-term sea level dataset shows ocean surface heights continuing to rise at faster and faster rates over decades of observations.

Global average sea level rose by about 0.3 inches (0.76 centimeters) from 2022 to 2023, a relatively large jump due mostly to a warming climate and the development of a strong El Niño. The total rise is equivalent to draining a quarter of Lake Superior into the ocean over the course of a year.

This NASA-led analysis is based on a sea level dataset featuring more than 30 years of satellite observations, starting with the U.S.-French TOPEX/Poseidon mission, which launched in 1992. The Sentinel-6 Michael Freilich mission, which launched in November 2020, is the latest in the series of satellites that have contributed to this sea level record.

The data shows that global average sea level has risen a total of about 4 inches (9.4 centimeters) since 1993. The rate of this increase has also accelerated, more than doubling from 0.07 inches (0.18 centimeters) per year in 1993 to the current rate of 0.17 inches (0.42 centimeters) per year.

“Current rates of acceleration mean that we are on track to add another 20 centimeters of global mean sea level by 2050, doubling the amount of change in the next three decades compared to the previous 100 years and increasing the frequency and impacts of floods across the world,” said Nadya Vinogradova Shiffer, director for the NASA sea level change team and the ocean physics program in Washington.

Seasonal Effects

Global sea level saw a significant jump from 2022 to 2023 due mainly to a switch between La Niña and El Niño conditions. A mild La Niña from 2021 to 2022 resulted in a lower-than-expected rise in sea level that year. A strong El Niño developed in 2023, helping to boost the average amount of rise in sea surface height.

La Niña is characterized by cooler-than-normal ocean temperatures in the equatorial Pacific Ocean. El Niño involves warmer-than-average ocean temperatures in the equatorial Pacific. Both periodic climate phenomena affect patterns of rainfall and snowfall as well as sea levels around the world.

“During La Niña, rain that normally falls in the ocean falls on the land instead, temporarily taking water out of the ocean and lowering sea levels,” said Josh Willis, a sea level researcher at NASA’s Jet Propulsion Laboratory in Southern California. “In El Niño years, a lot of the rain that normally falls on land ends up in the ocean, which raises sea levels temporarily.”

A Human Footprint

Seasonal or periodic climate phenomena can affect global average sea level from year to year. But the underlying trend for more than three decades has been increasing ocean heights as a direct response to global warming due to the excessive heat trapped by greenhouse gases in Earth’s atmosphere.

“Long-term datasets like this 30-year satellite record allow us to differentiate between short-term effects on sea level, like El Niño, and trends that let us know where sea level is heading,” said Ben Hamlington, lead for NASA’s sea level change team at JPL.

These multidecadal observations wouldn’t be possible without ongoing international cooperation, as well as scientific and technical innovations by NASA and other space agencies. Specifically, radar altimeters have helped produce ever-more precise measurements of sea level around the world. To calculate ocean height, these instruments bounce microwave signals off the sea surface, recording the time the signal takes to travel from a satellite to Earth and back, as well as the strength of the return signal.

The researchers also periodically cross-check those sea level measurements against data from other sources. These include tide gauges, as well as satellite measurements of factors like atmospheric water vapor and Earth’s gravity field that can affect the accuracy of sea level measurements. Using that information, the researchers recalibrated the 30-year dataset, resulting in updates to sea levels in some previous years. That includes a sea level rise increase of 0.08 inches (0.21 centimeters) from 2021 to 2022.

When researchers combine space-based altimetry data of the oceans with more than a century of observations from surface-based sources, such as tide gauges, the information dramatically improves our understanding of how sea surface height is changing on a global scale. When these sea level measurements are combined with other information, including ocean temperature, ice loss, and land motion, scientists can decipher why and how seas are rising.

Learn more about sea level and climate change:

https://sealevel.nasa.gov/

News Media Contacts

Jane J. Lee / Andrew Wang
Jet Propulsion Laboratory, Pasadena, Calif.
818-354-0307 / 626-379-6874
jane.j.lee@jpl.nasa.gov / andrew.wang@jpl.nasa.gov

2024-031

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Naomi Hartono

NASA’s Chandra Identifies an Underachieving Black Hole

This image shows a quasar, a rapidly growing supermassive black hole, which is not achieving what astronomers would expect from it, as reported in our latest press release. Data from NASA’s Chandra X-ray Observatory (blue) and radio data from the NSF’s Karl G. Jansky’s Very Large Array (red) reveal some of the evidence for this quasar’s disappointing impact on its host galaxy.

Known as H1821+643, this quasar is about 3.4 billion light-years from Earth. Quasars are a rare and extreme class of supermassive black holes that are furiously pulling material inwards, producing intense radiation and sometimes powerful jets. H1821+643 is the closest quasar to Earth in a cluster of galaxies.

Quasars are different than other supermassive black holes in the centers of galaxy clusters in that they are pulling in more material at a higher rate. Astronomers have found that non-quasar black holes growing at moderate rates influence their surroundings by preventing the intergalactic hot gas from cooling down too much. This regulates the growth of stars around the black hole.

The influence of quasars, however, is not as well known. This new study of H1821+643 that quasars — despite being so active — may be less important in driving the fate of their host galaxy and cluster than some scientists might expect.

To reach this conclusion the team used Chandra to study the hot gas that H1821+643 and its host galaxy are shrouded in. The bright X-rays from the quasar, however, made it difficult to study the weaker X-rays from the hot gas. The researchers carefully removed the X-ray glare to reveal what the black hole’s influence is, which is reflected in the new composite image showing X-rays from hot gas in the cluster surrounding the quasar. This allowed them to see that the quasar is actually having little effect on its surroundings.

Using Chandra, the team found that the density of gas near the black hole in the center of the galaxy is much higher, and the gas temperatures much lower, than in regions farther away. Scientists expect the hot gas to behave like this when there is little or no energy input (which would typically come from outbursts from a black hole) to prevent the hot gas from cooling down and flowing towards the center of the cluster.

A paper describing these results has been accepted into the Monthly Notices of the Royal Astronomical Society and is available online. The authors are Helen Russell (University of Nottingham, UK), Paul Nulsen (Center for Astrophysics | Harvard & Smithsonian), Andy Fabian (University of Cambridge, UK), Thomas Braben (University of Nottingham), Niel Brandt (Penn State University), Lucy Clews (University of Nottingham), Michael McDonald (Massachusetts Institute of Technology), Christopher Reynolds (University of Maryland), Jeremy Saunders (Max Planck Institute for Extraterrestrial Research), and Sylvain Veilleux (University of Maryland).

NASA’s Marshall Space Flight Center manages the Chandra program. The Smithsonian Astrophysical Observatory’s Chandra X-ray Center controls science from Cambridge Massachusetts and flight operations from Burlington, Massachusetts.

Read more from NASA’s Chandra X-ray Observatory.

For more Chandra images, multimedia and related materials, visit:

https://www.nasa.gov/mission/chandra-x-ray-observatory/

Visual Description:

This composite image shows a quasar, a rare and extreme class of supermassive black hole, that’s located about 3.4 billion light-years from Earth.

At the center of the image is a bright, white, circular light, similar to the beam of a flashlight if it was pointed directly toward you. A fuzzy, bar-shaped structure of red-colored radio light, slightly larger than the width of the white light, surrounds the circular structure. The red bar also extends above and below the white light, stretching in a somewhat straight line from about the one o’clock position to the seven o’clock position on a clock face.

On either side of the red bar, X-ray light is present as blue, wispy clouds of hot gas that are brighter closer to the red and white features. The brighter clouds represent more dense gas.

News Media Contact

Megan Watzke
Chandra X-ray Center
Cambridge, Mass.
617-496-7998

Jonathan Deal
Marshall Space Flight Center
Huntsville, Ala.
256-544-0034

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Lee Mohon

Contract Specialist Dr. Danielle May

“Not only was I going to school, raising a family, and working a full-time job, but I was also the state director for my sorority [and was responsible for] over 1,200 members at one time. And I think it comes down to perseverance. At the end of the day, you’re going to do what needs to be done if you truly want to get it done. You’re going to make the sacrifices that you need to make in order to be successful.

“I’m a night person. So my big homework hours were between 11 p.m. and 3 a.m. I made the time because it was important. And we all do that — we make the time for what’s important to us. I hear people say, ‘There’s no way I could have done that.’ Well, it’s easy when you truly want something with your whole heart.

“…When I actually defended my dissertation and my family was able to attend, that’s when it hit them. They were like, ‘You did all this while we were asleep? You did all this while we were on family vacation?’ I could feel the pride from them because for them, it seemed like it was seamless. But for me, it was heavy. It was heavy, but necessary.

“I believe in giving people their roses while they’re still here to collect them. A few years before I started my doctorate program, my mother had a medical issue and we thought we were going to lose her. And that was the point that I said, ‘I need to go to school and I need to do this for her, because I want her to see me walk across that stage.’

“[Getting my doctorate] made me sit up a little straighter. It’s made me smile a little bit more. It’s made me feel like I can do anything. Not many people can say that.

“…It is something that at the end of the day, no one could ever take away from me. Ever. No matter how much money I have in the bank, no matter where I live or if I have a roof over my head, no one can ever take that away.”

– Dr. Danielle May, Contract Specialist, NASA’s Langley Research Center

Image Credit: NASA/Mark Knopp
Interviewer: NASA/Thalia Patrinos

Check out some of our other Faces of NASA. 

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Tahira S. Allen