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posted by janrinok on Monday June 01 2020, @03:13PM   Printer-friendly
from the slip-slidin'-away-now dept.

Antarctic ice sheets capable of retreating up to 50 meters per day:

The study, led by the Scott Polar Research Institute at the University of Cambridge, used patterns of delicate wave-like ridges on the Antarctic seafloor to calculate how quickly the ice retreated roughly 12,000 years ago during regional deglaciation.

The ridges were produced where the ice sheet began to float, and were caused by the ice squeezing the sediment on the seafloor as it moved up and down with the movement of the tides. The images of these landforms are at unprecedented sub-metre resolution and were acquired from an autonomous underwater vehicle (AUV) operating about 60 metres above the seabed. The results are reported in the journal Science.

While modern satellites are able to gather detailed information about the retreat and thinning rates of the ice around Antarctica, the data only goes back a few decades. Calculating the maximum speed at which an ice sheet can retreat, using sets of these seafloor ridges, reveals historic retreat rates that are almost ten times faster than the maximum observed rates of retreat today.

"By examining the past footprint of the ice sheet and looking at sets of ridges on the seafloor, we were able to obtain new evidence on maximum past ice retreat rates, which are very much faster than those observed in even the most sensitive parts of Antarctica today," said lead author Professor Julian Dowdeswell, Director of the Scott Polar Research Institute.

[...] They calculated that the ice was retreating as much as 40 to 50 metres per day during this period, a rate that equates to more than 10 kilometres per year. In comparison, modern satellite images show that even the fastest-retreating grounding lines in Antarctica today, for example in Pine Island Bay, are much slower than these geological observations, at only about 1.6 kilometres per year.

"The deep marine environment is actually quite quiet offshore of Antarctica, allowing features such as these to be well-preserved through time on the seafloor," said Dowdeswell. "We now know that the ice is capable of retreating at speeds far higher than what we see today. Should climate change continue to weaken the ice shelves in the coming decades, we could see similar rates of retreat, with profound implications for global sea level rise."


Original Submission

Journal Reference
J. A. Dowdeswell, C. L. Batchelor, A. Montelli, et al. Delicate seafloor landforms reveal past Antarctic grounding-line retreat of kilometers per year [$], Science (DOI: 10.1126/science.aaz3059)

 
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  • (Score: 0) by Anonymous Coward on Monday June 01 2020, @04:20PM (3 children)

    by Anonymous Coward on Monday June 01 2020, @04:20PM (#1001752)

    If my rudimentary internet search is right, the mean surface antarctic temp has moved 8deg C since 12k yr ago, so comparing this with today is about as useful as reading the inevitable cornflake comments this article will attract.

    Interesting summary nonetheless.

  • (Score: 0) by Anonymous Coward on Monday June 01 2020, @04:45PM (2 children)

    by Anonymous Coward on Monday June 01 2020, @04:45PM (#1001767)

    Since it is not an issue, you won’t mind giving that land to test new economic systems if it does melt
    https://soylentnews.org/article.pl?sid=20/05/30/0355222 [soylentnews.org]

    • (Score: 1, Funny) by Anonymous Coward on Monday June 01 2020, @05:02PM

      by Anonymous Coward on Monday June 01 2020, @05:02PM (#1001781)

      Nah will move to Eigg tho. The moor is 392m above current sea level, should be plenty for 106 when the sheets melt.

    • (Score: 1) by khallow on Tuesday June 02 2020, @07:42AM

      by khallow (3766) Subscriber Badge on Tuesday June 02 2020, @07:42AM (#1002082) Journal
      I wouldn't mind "giving" that land even if it doesn't. Antarctica will be the last great land rush, ice or no ice.