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By NASA
4 min read
Preparations for Next Moonwalk Simulations Underway (and Underwater)
This image, taken from a data visualization, shows Arctic sea ice minimum extent on September 11, 2024. The yellow boundary shows the minimum extent averaged over the 30-year period from 1981 to 2010. Download high-resolution video and images from NASA’s Scientific Visualization Studio: https://svsdev.gsfc.nasa.gov/5382NASA’s Scientific Visualization Studio/Trent L. Schindler Arctic sea ice retreated to near-historic lows in the Northern Hemisphere this summer, likely melting to its minimum extent for the year on Sept.11, 2024, according to researchers at NASA and the National Snow and Ice Data Center (NSIDC). The decline continues the decades-long trend of shrinking and thinning ice cover in the Arctic Ocean.
The amount of frozen seawater in the Arctic fluctuates during the year as the ice thaws and regrows between seasons. Scientists chart these swings to construct a picture of how the Arctic responds over time to rising air and sea temperatures and longer melting seasons. Over the past 46 years, satellites have observed persistent trends of more melting in the summer and less ice formation in winter.
This summer, Arctic sea ice decreased to a its minimum extent on September 11, 2024. According to the National Snow and Ice Data Center this is the 7th lowest in the satellite record). The decline continues the long-term trend of shrinking ice cover in the Arctic Ocean.
Credit: NASA’s Goddard Space Flight Center Tracking sea ice changes in real time has revealed wide-ranging impacts, from losses and changes in polar wildlife habitat to impacts on local communities in the Arctic and international trade routes.
This year, Arctic sea ice shrank to a minimal extent of 1.65 million square miles (4.28 million square kilometers). That’s about 750,000 square miles (1.94 million square kilometers) below the 1981 to 2010 end-of-summer average of 2.4 million square miles (6.22 million square kilometers). The difference in ice cover spans an area larger than the state of Alaska. Sea ice extent is defined as the total area of the ocean with at least 15% ice concentration.
Seventh-Lowest in Satellite Record
This year’s minimum remained above the all-time low of 1.31 million square miles (3.39 million square kilometers) set in September 2012. While sea ice coverage can fluctuate from year to year, it has trended downward since the start of the satellite record for ice in the late 1970s. Since then, the loss of sea ice has been about 30,000 square miles (77,800 square kilometers) per year, according to NSIDC.
Scientists currently measure sea ice extent using data from passive microwave sensors aboard satellites in the Defense Meteorological Satellite Program, with additional historical data from the Nimbus-7 satellite, jointly operated by NASA and the National Oceanic and Atmospheric Administration (NOAA).
Today, the overwhelming majority of ice in the Arctic Ocean is thinner, first-year ice, which is less able to survive the warmer months. There is far, far less ice that is three years or older now,
Nathan Kurtz
Chief, NASA's Cryospheric Sciences Laboratory
Sea ice is not only shrinking, it’s getting younger, noted Nathan Kurtz, lab chief of NASA’s Cryospheric Sciences Laboratory at the agency’s Goddard Space Flight Center in Greenbelt, Maryland.
“Today, the overwhelming majority of ice in the Arctic Ocean is thinner, first-year ice, which is less able to survive the warmer months. There is far, far less ice that is three years or older now,” Kurtz said.
Ice thickness measurements collected with spaceborne altimeters, including NASA’s ICESat and ICESat-2 satellites, have found that much of the oldest, thickest ice has already been lost. New research out of NASA’s Jet Propulsion Laboratory in Southern California shows that in the central Arctic, away from the coasts, fall sea ice now hovers around 4.2 feet (1.3 meters) thick, down from a peak of 8.8 feet (2.7 meters) in 1980.
Another Meager Winter Around Antarctica
Sea ice in the southern polar regions of the planet was also low in 2024. Around Antarctica, scientists are tracking near record-low sea ice at a time when it should have been growing extensively during the Southern Hemisphere’s darkest and coldest months.
Ice around the continent is on track to be just over 6.6 million square miles (16.96 million square kilometers). The average maximum extent between 1981 and 2010 was 7.22 million square miles (18.71 million square kilometers).
The meager growth so far in 2024 prolongs a recent downward trend. Prior to 2014, sea ice in the Antarctic was increasing slightly by about 1% per decade. Following a spike in 2014, ice growth has fallen dramatically. Scientists are working to understand the cause of this reversal. The recurring loss hints at a long-term shift in conditions in the Southern Ocean, likely resulting from global climate change.
“While changes in sea ice have been dramatic in the Arctic over several decades, Antarctic sea ice was relatively stable. But that has changed,” said Walt Meier, a sea ice scientist at NSIDC. “It appears that global warming has come to the Southern Ocean.”
In both the Arctic and Antarctic, ice loss compounds ice loss. This is due to the fact that while bright sea ice reflects most of the Sun’s energy back to space, open ocean water absorbs 90% of it. With more of the ocean exposed to sunlight, water temperatures rise, further delaying sea ice growth. This cycle of reinforced warming is called ice-albedo feedback.
Overall, the loss of sea ice increases heat in the Arctic, where temperatures have risen about four times the global average, Kurtz said.
About the Author
Sally Younger
Senior Science Writer
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Last Updated Sep 24, 2024 LocationGoddard Space Flight Center Related Terms
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By NASA
5 Min Read Antarctic Sea Ice Near Historic Lows; Arctic Ice Continues Decline
On Feb. 20, 2024, Antarctic sea ice officially reached its minimum extent for the year. This cycle of growth and melting occurs every year, with the ice reaching its smallest size during the Southern Hemisphere's summer. Credits: NASA's Scientific Visualization Studio/Trent L. Schindler Sea ice at both the top and bottom of the planet continued its decline in 2024. In the waters around Antarctica, ice coverage shrank to near-historic lows for the third year in a row. The recurring loss hints at a long-term shift in conditions in the Southern Ocean, likely resulting from global climate change, according to scientists at NASA and the National Snow and Ice Data Center. Meanwhile, the 46-year trend of shrinking and thinning ice in the Arctic Ocean shows no sign of reversing.
“Sea ice acts like a buffer between the ocean and the atmosphere,” said ice scientist Linette Boisvert of NASA’s Goddard Space Flight Center in Greenbelt, Maryland. “Sea ice prevents much of the exchange of heat and moisture from the relatively warm ocean to the atmosphere above it.”
Less ice coverage allows the ocean to warm the atmosphere over the poles, leading to more ice melting in a vicious cycle of rising temperatures.
Historically, the area of sea ice surrounding the Antarctic continent has fluctuated dramatically from year to year while averages over decades have been relatively stable. In recent years, though, sea ice cover around Antarctica has plummeted.
On Feb. 20, 2024, Antarctic sea ice officially reached its minimum extent for the year. This cycle of growth and melting occurs every year, with the ice reaching its smallest size during the Southern Hemisphere’s summer. According to the National Snow and Ice Data Center, this marks the second-lowest sea ice extent recorded by satellites, reflecting a trend of declining coverage over time.
Credit: NASA’s Goddard Space Flight Center/Scientific Visualization Studio
Download this video in HD formats from https://svs.gsfc.nasa.gov/14538.
“In 2016, we saw what some people are calling a regime shift,” said sea ice scientist Walt Meier of the National Snow and Ice Data Center at the University of Colorado, Boulder. “The Antarctic sea ice coverage dropped and has largely remained lower than normal. Over the past seven years, we’ve had three record lows.”
This year, Antarctic sea ice reached its lowest annual extent on Feb. 20 with a total of 768,000 square miles (1.99 million square kilometers). That’s 30% below the 1981 to 2010 end-of-summer average. The difference in ice cover spans an area about the size of Texas. Sea ice extent is defined as the total area of the ocean in which the ice cover fraction is at least 15%.
This year’s minimum is tied with February 2022 for the second lowest ice coverage around the Antarctic and close to the 2023 all-time low of 691,000 square miles (1.79 million square kilometers). With the latest ice retreat, this year marks the lowest three-year average for ice coverage observed around the Antarctic continent across more than four decades.
The changes were observed in data collected with microwave sensors aboard the Nimbus-7 satellite, jointly operated by NASA and the National Oceanic and Atmospheric Administration (NOAA), along with satellites in the Defense Meteorological Satellite Program.
NASA’s Earth Observatory: Antarctic Sea Ice at Near-Historic Lows Meanwhile, at the other end of the planet, the maximum winter ice coverage in the Arctic Ocean is consistent with an ongoing 46-year decline. Satellite images reveal that the total area of the Arctic Ocean covered in sea ice reached 6 million square miles (15.65 million square kilometers) on March 14. That’s 247,000 square miles (640,000 square kilometers) less ice than the average between 1981 and 2010. Overall, the maximum winter ice coverage in the Arctic has shrunk by an area equivalent to the size of Alaska since 1979.
This year’s Arctic ice maximum is the 14th lowest on record. Complex weather patterns make it difficult to predict what will happen in any given year.
The Arctic Ocean sea ice reached its annual maximum on March 14, continuing the long-term decline in ice at the poles.Chart by Lauren Dauphin/NASA Earth Observatory, using data from the National Snow and Ice Data Center. Shrinking ice makes Earth more susceptible to solar heating. “The sea ice and the snow on top of it are very reflective,” Boisvert said. “In the summer, if we have more sea ice, it reflects the Sun’s radiation and helps keep the planet cooler.”
On the other hand, the exposed ocean is darker and readily absorbs solar radiation, capturing and retaining that energy and ultimately contributing to warming in the planet’s oceans and atmosphere.
Sea ice around the poles is more susceptible to the weather than it was a dozen years ago. Ice thickness measurements collected with laser altimeters aboard NASA’s ICESat-2 satellite show that less ice has managed to stick around through the warmer months. This means new ice must form from scratch each year, rather than building on old ice to make thicker layers. Thinner ice, in turn, is more prone to melting than multi-year accumulations.
“The thought is that in a couple of decades, we’re going to have these essentially ice-free summers,” Boisvert said, with ice coverage reduced below 400,000 square miles (1 million square kilometers) and most of the Arctic Ocean exposed to the Sun’s warming glare.
It’s too soon to know whether recent sea ice lows at the South Pole point to a long-term change rather than a statistical fluctuation, but Meier believes long term declines are inevitable.
“It’s only a matter of time,” he said. “After six, seven, eight years, it’s starting to look like maybe it’s happening. It’s just a question of whether there’s enough data to say for sure.”
Reference: NSIDC Sea Ice Index Daily and Monthly Image Viewer By James Riordon
NASA’s Earth Science News Team
Media contact: Elizabeth Vlock
NASA Headquarters
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Last Updated Mar 25, 2024 EditorGoddard Digital TeamLocationGoddard Space Flight Center Related Terms
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By European Space Agency
Video: 00:00:20 In November 2023, the A23a mega iceberg set sail after being grounded on the ocean floor for well over 40 years. Now, driven by winds and currents, A23a is heading away from Antarctic waters as seen in this new animation.
The iceberg calved from West Antarctica in 1986 but quickly grounded itself in the Weddell Sea where it remained for over four decades. At around 4000 sq km in area, more than four times the size of New York City, and just over 280 m thick, the berg currently holds the title for world’s largest iceberg.
The animation uses sea-ice concentration data and shows the iceberg’s movements between 1 November 2023 to 23 January 2024. Similar to many icebergs originating from the Weddell sector, A23a is likely to be expelled into the Antarctic Circumpolar Current – propelling it towards the South Atlantic along a trajectory commonly referred to as ‘iceberg alley’.
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By NASA
1 min read
Preparations for Next Moonwalk Simulations Underway (and Underwater)
The Galactic/Extragalactic ULDB Spectroscopic Terahertz Observatory (GUSTO) awaits its flight on a scientific balloon with a picturesque view of Antarctica’s Mount Erebus in the distance. GUSTO successfully launched Dec. 31, 7:30 p.m. local time (Dec. 31, 1:30 a.m. EST) and remains in flight.NASA/Scott Battaion High above the icy landscape of Earth’s southernmost continent, the Galactic/Extragalactic ULDB Spectroscopic Terahertz Observatory (GUSTO) scientific balloon mission has been afloat for more than 15 days since its launch from McMurdo, Antarctica, on Dec. 31, 7:30 p.m. local time (Dec. 31, 1:30 a.m. EST).
GUSTO is mapping a large portion of the Milky Way galaxy and Large Magellanic Cloud to help scientists study the interstellar medium. The observatory is transmitting the data it collects back to watchful teams on the ground as it steadily circumnavigates the South Pole around 120,000+ feet.
GUSTO is flying on a 39 million cubic-foot zero-pressure scientific balloon, which is so large it could easily fit 195 blimps inside of it. The balloon is used to fly missions for long periods of time during the Austral Summer over Antarctica. GUSTO is aiming for a NASA record of 55+ days in flight to achieve its science goals.
For more information on NASA’s Scientific Balloon Program, managed at NASA’s Wallops Flight Facility in Virginia, click here. To track the GUSTO mission in real-time, visit NASA’s Columbia Scientific Balloon Facility website.
Check out more photos from GUSTO's launch here Share
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Last Updated Jan 16, 2024 EditorOlivia F. LittletonContactOlivia F. Littletonolivia.f.littleton@nasa.gov Related Terms
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By European Space Agency
New research, based largely on information from the Copernicus Sentinel-1 and ESA’s CryoSat satellite missions, has revealed alarming findings about the state of Antarctica's ice shelves: 40% of these floating shelves have significantly reduced in volume over the past quarter-century. While this underscores the accelerating impacts of climate change on the world's southernmost continent, the picture of ice deterioration is mixed.
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