Antarctica’s sleeping ice giant could wake soon

Apr 12, 2017

By Jane Qiu

On a glorious January morning in 2015, the Australian icebreaker RSV Aurora Australis was losing a battle off the coast of East Antarctica. For days, the ship had been trying to push through heavy sea ice. It rammed into the pack, backed up and crashed forward again. But the ice, several metres thick, hardly budged. Stephen Rintoul, an oceanographer at the University of Tasmania in Hobart, Australia, nearly gave up his goal — to reach a part of the continent that had thwarted all previous expeditions. “I really thought that would be it,” he says. “It’d be another failed attempt.”

Then the weather came to the rescue, with a wind change that blew the ice away from the shore, opening a path through the pack. The ship managed to break free and wove its way through 100 kilometres of ice, reaching the edge of the frozen continent shortly after midnight. Rintoul and his team were the first scientists to reach the Totten Ice Shelf — a vast floating ice ledge that fronts the largest glacier in East Antarctica. “It was a really exhilarating experience,” says Rintoul, chief scientist of the expedition.

The team had to work fast before the ice closed again and blocked any escape. For more than 12 hours, Rintoul and his colleagues carried on non-stop, probing the temperature and salinity of the water, the speed and direction of ocean currents as well as the shape and depth of the ocean floor. They also deployed instruments that would continue taking measurements after the ship had departed.

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4 comments on “Antarctica’s sleeping ice giant could wake soon

  • @OP – These first direct observations confirmed a fear that researchers had long harboured: that warm waters from the surrounding ocean can sneak underneath the floating glacier tongue and eat the ice away from below1. “This could explain why Totten has been thinning in the past few decades,” says Rintoul.

    Findings such as these are revealing some scary truths about East Antarctica — the vast, remote landmass to the east of the Transantarctic Mountains (see ‘Ice king’). This region is about as big as the entire United States and the majority of it stands on a high plateau up to 4,093 metres above sea level, where temperatures can plunge to −95 °C. Because the East Antarctic Ice Sheet seems so cold and isolated, researchers thought that it had been stable in the past and was unlikely to change in the future — a stark contrast to the much smaller West Antarctic Ice Sheet, which has raised alarms because many of its glaciers are rapidly retreating.

    In the past few years, however, “almost everything we thought we knew about East Antarctica has turned out to be wrong”, says Tas van Ommen, a glaciologist at the Australian Antarctic Division in Kingston, near Hobart. By flying across the continent on planes with instruments that probe beneath the ice, his team found that a large fraction of East Antarctica is well below sea level, which makes it more vulnerable to the warming ocean than previously thought.

    The fact that Antarctica is essentially a group of islands with gaps filled with ice, rather than a solid land mass, means that it is vulnerable to rising sea levels floating the ice off the seabed, and letting currents of warmed sea water get under it, and melt it from below!

    Floating ice sheets around the edges of Antarctica, are already vulnerable to these warmed waters.

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  • The break-ups continue!

    The crack in the Larsen C Ice Shelf that looks set to spawn a giant berg has suddenly forked.

    Satellite imagery of the 180km-long fissure acquired in recent days shows a clear branching behaviour at its tip.

    Quite what this means for the future evolution of the crack and the putative 5,000-sq-km berg remains to be seen.

    Larsen C is a floating projection of ice pushing east from the Antarctic Peninsula. It covers an area of the Weddell Sea the size of Wales.

    The berg, when it calves, will remove about a quarter of the total shelf extent and could leave the remaining structure in a less stable configuration.

    Scientists are concerned that Larsen C may be developing in a similar way to its siblings, Larsen A and Larsen B, which eventually collapsed at the turn of the century following their own big calving events.

    The 10km-long fork does not increase the length of the rift; it merely gives it a two-pronged tip. The new branch has opened on the seaward side of the main crack.

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  • Hi, Alan (others),

    I read a couple of articles about the arctic summer sea ice, which is projected to be non-existent in about twenty years. Hooray!! I posted an article about that on the Scientists Are Running thread. This has serious ramifications, will aggravate global warming.

    It’s too bad that denial of solid evidence based on research conducted by experts is not an impeachable offense. Doesn’t that make one unfit for office? Doesn’t that imply mental incompetence (irrationality) and/or moral turpitude. The latter per se cannot get you removed from office; the former should be able to. (“Should”! Too many “shoulds” in the world.)

    Article II, Section 1, Clause 6 of the Constitution states:

    In Case of the Removal of the President from Office, or of his Death, Resignation, or Inability to discharge the Powers and Duties of the said Office, the Same shall devolve on the Vice President, and the Congress may by Law provide for the Case of Removal, Death, Resignation or Inability, both of the President and Vice President, declaring what Officer shall then act as President, and such Officer shall act accordingly, until the Disability be removed, or a President shall be elected.

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  • Dan #3
    May 2, 2017 at 6:15 pm Quote:-

    In Case of the Removal of the President from Office,
    or of his Death, Resignation,
    or Inability to discharge the Powers and Duties of the said Office,

    The evidence just keeps right on mounting – but of course Trumpie cheerleaders are not into “evidence”.

    They just love “alternative facts” and “false news”, which tell the uneducated red-neck dimwits, that their (simplistic, Faux and Dimbart) adopted stupidity, is “superior thinking” to that of those high-fallutin’ experts who write those complex predictive reports they don’t bother to read and cannot understand!

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