Seasonal change in Antarctic ice sheet movement observed for first time – but what does it mean?

Posted: October 7, 2022 by oldbrew in data, Natural Variation, research, satellites, sea levels, Uncertainty

Antarctica’s George VI Ice Shelf [image credit: CIRES Colorado Univ.]

Assumptions challenged by new data. Talk of “potentially important implications for global sea-level rise estimates”.
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Some estimates of Antarctica’s total contribution to sea-level rise may be over- or underestimated, after researchers detected a previously unknown source of ice loss variability, says

The researchers, from the University of Cambridge and Austrian engineering company ENVEO, identified distinct, seasonal movements in the flow of land-based ice draining into George VI Ice Shelf—a floating platform of ice roughly the size of Wales—on the Antarctic Peninsula.

Using imagery from the Copernicus/European Space Agency Sentinel-1 satellites, the researchers found that the glaciers feeding the ice shelf speed up by approximately 15% during the Antarctic summer.

This is the first time that such seasonal cycles have been detected on land ice flowing into ice shelves in Antarctica. The results are reported in the journal The Cryosphere.

While it is not unusual for ice flow in Arctic and Alpine regions to speed up during summer, scientists had previously assumed that ice in Antarctica was not subject to the same seasonal movements, especially where it flows into large ice shelves and where temperatures are below freezing for most of the year.

This assumption was also, in part, fuelled by a lack of imagery collected over the icy continent in the past. “Unlike the Greenland Ice Sheet, where a high quantity of data has allowed us to understand how the ice moves from season to season and year to year, we haven’t had comparable data coverage to look for such changes over Antarctica until recently,” said Karla Boxall from Cambridge’s Scott Polar Research Institute (SPRI), the study’s first author.

“Observations of ice-speed change in the Antarctic Peninsula have typically been measured over successive years, so we’ve been missing a lot of the finer detail about how flow varies from month to month throughout the year,” said co-author Dr. Frazer Christie, also from SPRI.

Full article here.

  1. […] Seasonal change in Antarctic ice sheet movement observed for first time – but what does it mean? |… […]

  2. Jim says:

    Interesting, ice melts when warmed? Gee, it floats and is cold also. Great in drinks. And this or that is degreed science? When did the great dumbing occur?

  3. oldbrew says:

    They still don’t know why the seasonal variability shows up in winter. Temps are supposed to be below zero all the time in Antarctic winter, and most of the rest of the year also.

    Both surface and oceanic forcing mechanisms are evaluated as potential controls on this seasonality, although insufficient observational evidence currently exists with which to verify the relative importance of each. Elucidating the precise surface and/or ocean mechanisms governing GVIIS’ outlet glacier flow variability is therefore a critical area for future research.

  4. Margaret H Smith says:

    Makes you wonder how they made dire predictions in the past when every year they make new discoveries – they seem to have known very little 20 years ago. Anyhow, I always understood that when glaciers advance they are getting heavier, bigger. Hasn’t the Antarctic been reaching record lows in recently, like -61.7°C?
    We need to get schooling back into the hands of teachers, not indoctrinated.

  5. catweazle666 says:

    Don’t you just love this “Settled Science”?

  6. Every new climate science discovery is new knowledge of things that have gone on for hundreds, thousands, and millions of years, while climate changed with alternating warmer and colder time periods.
    Now, in the coldest warm period of the last hundreds, thousands, and millions of years, they celebrate every new discovery of old natural processes with some twist of alarm.
    They never let a piece of new knowledge go to waste, promoting their agendas.

    In this article that was referenced: ’Ice shelves hold back Antarctica’s glaciers from adding to sea levels, but they’re crumbling’

    This was written: “we show these ice shelves have significantly reduced in area over the last 25 years due to more and more icebergs breaking off. Overall, the net loss of ice is about 6,000 billion tons since 1997”

    That is equivalent to a huge IR out when that ice was formed, thousands or millions of years before, and is therefore equivalent to many watts per meter squared of cooling that happened in modern times as a result of thawing of the ice which had been formed in a much warmer time. Ice formed and sequestered in warmest times is responsible for cooling by thawing ice in cooler times and this warm time is cooler than all past warmer times.

    They wrote about the net loss of 6,000 billion tons of ice since 1997 and this is just in one region of Antarctica. That is equivalent to much cooling of the oceans, just like ice we formed in our freezer cools our ice chest, days or weeks or months later at the beach. Yet, cooling by thawing ice is nowhere in their Climate System Energy Balance Charts. Cooling by thawing ice is nowhere in their energy balance theory for the cooling during a major ice age when much of the northern hemisphere is covered by ice that has to thaw every summer and much even in winter.

    So, They Wrote:
    Seasonal change in Antarctic ice sheet movement observed for first time – but what does it mean?

    They should not be allowed to have it both ways. When ice that was formed during much warmer times, hundreds, thousands, and/or millions of years ago, thaws in modern times, the cooling by thawing ice must be included in Energy Balance Charts and Theory and Models and attributed to the IR out that occurred during much warmer times, hundreds, thousands, and/or millions of years ago.

    Heat energy is stored in oceans in tropical regions and transported by ocean currents to polar regions where Evaporation and IR out in warmest times is responsible for cooling that actually occurs during colder times, hundreds, thousands, and/or millions of years later, as in now in modern warm times that are cooler than millions of years ago due to the thawing of the sequestered ice.

    Either Quit writing that much ice is thawing, or account for the cooling by the thawing ice.

    If Consensus Climate Balance does not properly include the IR out forming ice in warmest times that causes cooling by thawing ice in coldest times, the theory and models and climate projections are much worse than worthless, they cause harm from pretending to fix something they have too little knowledge of.

  7. Gamecock says:

    “Every new climate science discovery is new knowledge of things that have gone on for hundreds, thousands, and millions of years”

    Yep. Gamecock’s theory is that after 4.5 billion years, the solar system is pretty well sorted. Yeah, a big ice sheet could break off Antarctica. An asteroid the size of Oklahoma could strike the earth. A Tunguska meteor could hit Moscow (wouldn’t that set off the religiocy?). But none of it is likely enough to even think about.

    Que sera, sera.

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