Faster in the Past: New seafloor images of West Antarctic Ice Sheet upend understanding of Thwaites Glacier retreat

Posted: September 7, 2022 by oldbrew in Geology, History, predictions, research, sea levels, volcanos
Tags: ,


Some like to call it the Doomsday Glacier. The research results are probably open to a variety of interpretations, in terms of predictions. But we’re told that whatever is being observed at present is by no means exceptional, making attempts at attribution of its ever-changing condition to human activity even more problematic. Volcanic activity is an obvious confounding factor here.
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The Thwaites Glacier in West Antarctica — about the size of Florida — has been an elephant in the room for scientists trying to make global sea level rise predictions, says Science Daily.

This massive ice stream is already in a phase of fast retreat (a “collapse” when viewed on geological timescales) leading to widespread concern about exactly how much, or how fast, it may give up its ice to the ocean.

The potential impact of Thwaites’ retreat is spine-chilling: a total loss of the glacier and surrounding icy basins could raise sea level from three to 10 feet.

A new study in Nature Geoscience led by marine geophysicist Alastair Graham at the University of South Florida’s College of Marine Science adds cause for concern. For the first time, scientists mapped in high-resolution a critical area of the seafloor in front of the glacier that gives them a window into how fast Thwaites retreated and moved in the past.

The stunning imagery shows geologic features that are new to science, and also provides a kind of crystal ball to see into Thwaites’ future. In people and ice sheets alike, past behavior is key to understanding future behavior.

The team documented more than 160 parallel ridges that were created, like a footprint, as the glacier’s leading edge retreated and bobbed up and down with the daily tides.

“It’s as if you are looking at a tide gauge on the seafloor,” Graham said. “It really blows my mind how beautiful the data are.”

Beauty aside, what’s alarming is that the rate of Thwaites’ retreat that scientists have documented more recently are small compared to the fastest rates of change in its past, said Graham.

To understand Thwaites’ past retreat, the team analyzed the rib-like formations submerged 700 meters (just under half a mile) beneath the polar ocean and factored in the tidal cycle for the region, as predicted by computer models, to show that one rib must have been formed every single day.

At some point in the last 200 years, over a duration of less than six months, the front of the glacier lost contact with a seabed ridge and retreated at a rate of more than 2.1 kilometers per year (1.3 miles per year) — twice the rate documented using satellites between 2011 and 2019.

“Our results suggest that pulses of very rapid retreat have occurred at Thwaites Glacier in the last two centuries, and possibly as recently as the mid-20th Century,” Graham said.

“Thwaites is really holding on today by its fingernails, and we should expect to see big changes over small timescales in the future-even from one year to the next-once the glacier retreats beyond a shallow ridge in its bed,” said marine geophysicist and study co-author Robert Larter from the British Antarctic Survey.

Full article here.
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Scientists discover 91 volcanoes below Antarctic ice sheet (August 2017):
Scientists have uncovered the largest volcanic region on Earth – two kilometres below the surface of the vast ice sheet that covers west Antarctica.

Comments
  1. […] Faster in the Past: New seafloor images of West Antarctic Ice Sheet upend understanding of Thwaites … […]

  2. Gamecock says:

    Science that scares.

    Science used to inform.

  3. oldbrew says:

    a total loss of the glacier and surrounding icy basins could raise sea level from three to 10 feet

    Assuming none of it would end up as snow on Antarctica?

  4. Glaciers retreat and sea ice thaws, this has happened during every past warm period, the retreat of the glaciers and the removal of the sea ice is necessary to have the evaporation and snowfall that rebuilds the Glaciers. It Does Not Snow in the Polar Regions when the Glaciers and Sea ice cover the Oceans! Ice is always flowing and pushing into the oceans and the ice is always depleting during the cold times. When the ice is not longer deep enough and heavy enough and is not flowing faster than the ice loss, the thawed ocean currents evaporate and supply the water vapor for the rebuilding of the glaciers. Ice Core Records document that ice accumulation is much more in warmest times, warmest times with open oceans are necessary to rebuild the land ice, the closer to the land that the open ocean gets, the better for rebuilding the ice. History and data shows the alternating warmer and colder times have always occurred, as far back as we have history and data.

    This modern warm time is “absolutely” necessary to rebuild the Polar Sequestered Ice.

  5. They have told us that Antarctica has gained ice for millions of years. We have Ice Core Records from Antarctica that go back 800 thousand years. The Ice Core Records show that Antarctica only gains ice during the warmest times. In coldest times there is little ice accumulation and ice depletes until the ice shelves can no longer be supported, and ice is no longer pushed into the oceans to keep them cold enough to form the sea ice which stops evaporation and snowfall.

  6. catweazle666 says:

    “…could raise sea level from three to 10 feet.”

    Heh, the magic word “could” again!

    And, if you take notice of the late, great Terry Pratchett – at least as credible as most “climate scientists” and a great deal more entertaining, the Solar System could be swallowed by a giant intergalactic stargoat.

    I’m not holding my breath.

  7. Russell Cook (@QuestionAGW) says:

    — “… a total loss of the glacier and surrounding icy basins could raise sea level from three to 10 feet. …”

    Old talking point, the U.S. partly public-funded news outlet PBS NewsHour regurgitated that bit about 10 feet in its Feb 19, 2020 discussion segment, “A risky expedition to study the ‘doomsday glacier” (15th paragraph: https://www.pbs.org/newshour/show/visiting-the-most-vulnerable-place-on-earth-the-doomsday-glacier ), featuring IPCC-associated scientist Dr David Holland. Back on that date, I counted that discussion as the 981st time where the NewsHour had a direct discussion / significant mention of the AGW issue dating all the way back in their broadcast history to 1996, during which its viewers only got to see seven instances where any semblance of science points from the skeptic side of the issue were presented. NONE of those skeptic points came from scientists. The NewsHour has barreled on relentlessly with their bias; Dr Holland has appeared two additional times while never being identified as having an association with the IPCC, and without facing any kind of rebuttal. In my ongoing count, ( http://gelbspanfiles.com/?page_id=3834 ), the ratio of pro-AGW scientists vs skeptic scientists now stands at 102-to-0, and the number of direct discussion / significant mentions of AGW is 1,356 with not a single new bit from the skeptic side.

  8. oldbrew says:

    Re. Russell Cook (@QuestionAGW) says…

    Yes, the worst products need the most publicity in order to keep selling to the gullible.

  9. Graeme No.3 says:

    A question: if “the more than 160 parallel sea floor ridges were created by the glacier’s leading edge bobbed up and down with the daily tides” surely the leading edge of the glacier must have been floating on the water. So we have the old floating ice melting and raising sea levels story yet again.
    “and as PREDICTED BY COMPUTER MODELS, to show that one rib must have been formed every single day. 160 ribs in 2,000 years? Even public servants work more than that.

  10. catweazle666 says:

    “So we have the old floating ice melting and raising sea levels story yet again.”

    Indeed.
    They never give up lying, do they?

  11. Graeme No.3 says:

    catweazle:
    What else have they got? No evidence of CO2 affecting the climate, computer models all, every one, inaccurate and a history of 34 of alarmist predictions of coming doom all not coming true.
    As my late father summed up the inadequate (often politicians) “you wouldn’t employ them to clean the latrines”.

  12. oldbrew says:

    Not trembling yet? 😆


    Excitable headline writer syndrome strikes again. Well, ‘data suggests’, so there.

    Cliscep takes a closer look at the relentless doom-mongering.
    https://cliscep.com/2022/01/05/the-doomsday-glacier/

  13. oldbrew says:

    If Thwaites doesn’t bother you the alarmists will try to find something else, even if they have to base it on models and frame it as a question.

    SEPTEMBER 14, 2022
    Are we missing a crucial component of sea-level rise?
    by Stanford University

    https://phys.org/news/2022-09-crucial-component-sea-level.html

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