Sea Ice That Slowed the Flow of Antarctic Glaciers Abruptly Shatters in Just 3 Days

Larsen-B Ice Shelf Remnants

Remnants of the Larsen-B ice shelf, filled in with seasonal ice in January 2016. Until January 2022, sea ice helped to buttress the nearby glaciers, slowing their flow into the sea. Credit: O.V.E.R.V.I.E.W

In just three days in late January, a mass of ice the size of Philadelphia fragmented from the Larsen-B embayment on the Antarctic Peninsula and floated away, after persisting there for more than a decade. NASA satellites captured the break-up between January 19 and 21, and with it saw calving of icebergs from Crane Glacier and its neighbors as the sea ice no longer buttressed their fronts. Now more vulnerable to melting and acceleration into the ocean, the glaciers that line the Antarctic Peninsula could add directly to sea level.

The Larsen Ice Shelf is situated along the northeast part of the Antarctic Peninsula, in the Weddell Sea. It is divided into four regions that occupy distinct embayments along the coastline, termed Larsen A, B, C, and D running north to south, each of which has undergone its own changes in the last few decades. The great mass of the ice shelf holds back the flow of many glaciers from the steep mountains towards the sea, where they contribute to sea level rise. Larsen-A was the first to disintegrate in 1995, followed by the abrupt partial collapse of Larsen-B in 2002. Larsen-C was the fourth largest Antarctic ice shelf as of July 2017, when a giant iceberg, named A68, calved from it, drawing worldwide attention to the region. Being furthest south, and hence least subject to warming, the only portion to be considered relatively stable is Larsen-D.

The loss of 3,250 square kilometers of ice from the Larsen B ice shelf in 2002 has been blamed on warmer ocean waters that melted it from below, and on the presence of meltwater on its surface, which also accelerated the loss of ice. With only a remnant portion left behind following the collapse, this section was much less stable and vulnerable to further disintegration. It grew thinner, which allowed glaciers on the landward side to flow faster. Sea ice formed in the newly opened area each winter, but it was not until 2011 that the sea ice remained year round, and did not melt the following spring. Between 2011 and 2022, the glaciers were somewhat stabilized because the remnant ice-shelf and sea ice that was permanent and attached, fast to the land, blocking their path into the ocean. But this large expanse shattered within three days in January, captured by NASA’s Terra and Aqua satellites.

Larsen-B Ice Shelf Collapsing I

Satellite image of the Larsen-B ice shelf collapsing in 2002. Credit: Oregon State University

Stef Lhermitte, a professor at TU Delft, who specializes in geoscience and remote sensing, explained to GlacierHub that “[it’s] difficult to tell what actually caused the disintegration as the sea ice was already showing cracks prior to the breakup.” Others have suggested warmer summer temperatures and foehn winds that carried warm and wet air to the region are partly responsible. The breakup of annual sea ice also occurred earlier than usual this year, which would have also helped destabilize the ice. Nonetheless, “such rapid breakups are often typical for fast ice, as fast ice is often a frozen collection of loose sea ice segments. Once this breaks, it quickly disintegrates,” Lhermitte added.

The recent break-up of ice in the Larsen-B embayment is important because the large glaciers that were buttressed by the ice are now exposed to the sea. Unlike sea ice and melt from an ice shelf, glaciers add directly to sea level. Although sea ice frozen to land is not as effective as holding back the flow of glaciers than the original ice shelf that was once present in the Larsen-B embayment, it has played a role in minimizing contributions to sea level rise from the Antarctic Peninsula over the last decade.

At the same time as scientists watched the breakup at Larsen-B, a new study was published that details the life cycle of the huge iceberg that calved from Larsen-C in 2017, A68. It was the sixth largest iceberg ever documented by satellite observations, comparable to the size of Delaware when it first broke from the ice shelf. A68 ceased to exist after three-and-a-half years, when it underwent rapid disintegration near the South Georgia Islands east of the southern tip of South America in January 2021.

A68 Iceberg Path

The path of the A68 iceberg between July 2017 and March 2021. As it drifted in the vicinity of the South Georgia islands, it is estimated to have dumped 152 billion tonnes of fresh water and nutrients into the surrounding ocean. (As seen in Figure 1). Credit: Laura Gerrish

Study lead author, Anne Braakmann-Folgmann, who has researched A68, explains that concerns were raised when it calved because “it reduced the remaining ice shelf area by a significant amount [and] Larsen-A and -B had already disintegrated.” Iceberg calving is known to influence the stability of the parent ice shelf that it leaves behind, but since 2017, what is left of Larsen-C has remained stable.

With warming temperatures and changing climatic patterns, notable events along the Larsen ice shelf are predicted to occur more frequently. Scientists are able to track each section of the Larsen Ice Shelf closely, documenting ice shelf collapse, growth of sea ice and the long survival of giant icebergs which threaten distant areas. As warming continues, questions prevail over how long the Larsen-D portion will remain stable. Its location closer to the South Pole has protected it from the impacts of climate change — so far. Reducing emissions is not only important for ice on the Antarctic Peninsula, but for the larger East and West Antarctic ice sheets too.

Reference: “Observing the disintegration of the A68A iceberg from space” by A. Braakmann-Folgmann, A. Shepherd, L. Gerrish, J. Izzard and A. Ridout, 10 January 2022, Remote Sensing of Environment.
DOI: 10.1016/j.rse.2021.112855

12 Comments on "Sea Ice That Slowed the Flow of Antarctic Glaciers Abruptly Shatters in Just 3 Days"

  1. Clyde Spencer | March 26, 2022 at 5:09 pm | Reply

    “The great mass of the ice shelf holds back the flow of many glaciers from the steep mountains towards the sea, …”

    I think that this is an overstatement. The shelf ice has inertia, which is a function of its mass and velocity. The mass increases with the thickness of the ice. However, the velocity of the floating ice is inherited from the moving glacial ice that it freezes to. The inertia resists any changes in velocity. However, the glacier experiences friction at its base that is much more important in controlling movement.

    “But this large expanse shattered within three days in January, captured by NASA’s Terra and Aqua satellites.”

    If the shelf ice was resisting the flow of the glaciers, it would be under compressive stress. The manner of breakup suggests tension, or pulling away from the glacier ice.

    Note the remark made, “[it’s] difficult to tell what actually caused the disintegration as the sea ice was already showing cracks prior to the breakup.”

    THEORY: “… concerns were raised when it calved because ‘it reduced the remaining ice shelf area by a significant amount [and] Larsen-A and -B had already disintegrated.’”
    REALITY: “but since 2017, what is left of Larsen-C has remained stable.”

  2. “Now more vulnerable to melting….”
    The great tragedy of ice is its vulnerability to melting. Good to point that out to the non-scientific reader.

    But this article — written in true Climate Doom News style — at the very least ought to offer some quantification of the amount of additional sea level rise that might be expected due to the breakup. The implication, of course, is that we should BE AFRAID. VERY AFRAID.

    One inch per century? Or what?

  3. I’m more concerned with the incoming planetary system.. I found out about it 8 years ago and have over 4,300 videos shared, to multiple sites. Look up Nibiru/Wormwood, Brandon Corey Nagley, World News Report Today, The Final Days, planet x hunter, Our Skies Today, The Two Preacher’s, mrmbb333… just to get you started.. others will pop up… good luck…

  4. Katrina Dymond | March 27, 2022 at 8:41 am | Reply

    I think the whole story should be told, not just “man made climate change” How about telling the whole story of how much our weakening magnetosphere (and shifting poles) lets in more space weather (heating the planet) How there is a 12,000 year cycle. I could go on,but I think you get my point. Yes we are a dirty species. Clear cutting forests that clean the air. Polluting the waters and land. The sun and our solar system play a bigger role than the media want to report.

  5. Philippe Pommez | March 27, 2022 at 2:00 pm | Reply

    We are a dirty species, yes, and ,worst, pretentious enough to think he can control such a complex system as the climate.

  6. Interesting.

    Initial Thoughts.

    1. Getting lost in the forest by examination of trees.Trees are trees, big or small. As are Glaciers and Big or Smal Chunks of ice. Question. Why does Ice Shatter? Drvers and forces responsible after examination in a controlled environment plaese.

    2. Water can exist in three main phases. Solid, Liquid, Gasseous. Composition of the same in terms of which phase is dominant will vary depending on the conditions over time.

    3. Earth has gone through multiple ice ages. Cooling and warming of the planet seems to be a regular feature. Understanding the drivers of the roots causes of what drves the phase transition could shed light on historicl calving of continental ice Shelfs in the Antartic. Also, predict the next phase.

    4. Remote sensing vide sattelites can only provide information and data. Useful no doubt. However, if data is not used effecetively to drive sensible decisions and desired outcomes, it is just useless data. Looking at data in isolation may lead us aastray.

    5.I also suspect that in the ancient past Earth may have been a Water Planet and Land may have emerged in recent times in human terms, considering the age of the planet in its evolution. All fossil records point to such a conclusion.

    6. Coming to the South Pole and Antartic Continental Ice shelf,its phase transition from Solid to Liquid and worry about the sea level increase needs to be accurately backed up with data based on laboratory experiments, keeping in mind the composition of the melting glaciers and the rate at which it is meling and acceleration of the same (if any) compared to historical data.

    7. Not even sure , it all wter on earth is narive to earth or brought in by other water carrying bodies from space and is alien.

    8. No doubt that the climate is changing. In some parts of the planet we are seeing Ice Age emergence, In others we see tropical and higher heat conditions. Temperature montoring at planetary surface level and determing the drivers of the same, could be more useful for intelligent/human life to survive the climate future (whatever it may be) and continue to exist by adapting.

    Views expressed are personal and not binding on anyone.

  7. If, instead of breaking off because the A68 iceshelf became large enough to break off, the calving is due to “warming seas” why did it break off in the middle of Southern winter, and didn’t shrink in size for several years?

    Isn’t glacier calving a sign of the glacier growing?

    Isn’t there any true scientists left or is everyone been assimilated by the climate emergency panic cult?

    Why is just about every scientist figuratively walking around wearing a “the end is near” sandwich board every where they go?

    • Edward Armstrong | March 28, 2022 at 12:54 pm | Reply

      The desperation of denialists gets ever more apparent as the scientific method progressively reveals more and more about the universe.

    • Gordon Chamberlain | March 28, 2022 at 6:41 pm | Reply

      “Isn’t there any true scientists left or is everyone been assimilated by the climate emergency panic cult?
      Why is just about every scientist figuratively walking around wearing a “the end is near” sandwich board every where they go?”
      Apparently you do not realize how inaccurate your perspective sounds. Have you read the IPCC reports.

  8. Yeah well maybe probably wasn’t natural for ice breakers to be running around for years breaking up the ice it’s not part of nature so I’m sure it’s probably not helping so keep plowing through it and drilling it and all the other stuff they’re doing an Antarctica shouldn’t take too much longer to destroy it like everything else

  9. A new ice age is coming , if not they will come and take those of us to another sustainable planet.✝️

  10. Listen to this angel sent to warn us to take action NOW , but it may be too late to fast, maybe not.
    She is one of GODs very important Angel’s warning us,cooperate and save the planet. GARY.✝️

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