Larsen C: One of the Biggest Bergs Ever just formed

July 12, 2017

That big Berg just dropped.

Above, I’ve been interviewing ice experts about this over recent months, including Eric Rignot, Jeremy Bassis, and Ted Scambos. They give background detail and implications.

Takeaway – not an unexpected or ominous event in itself, this calving is just another step in a process we are already following, and have been expecting.  Big picture estimates for sea level rise have risen steadily over recent decades as scientists better understand these ice dynamics.

BBC:

One of the biggest icebergs ever recorded has just broken away from Antarctica.

The giant block is estimated to cover an area of roughly 6,000 sq km; that’s about a quarter the size of Wales.

An US satellite observed the berg on Wednesday while passing over a region known as the Larsen C Ice Shelf.

Scientists were expecting it. They’d been following the development of a large crack in Larsen’s ice for more than a decade.

The rift’s propagation had accelerated since 2014, making an imminent calving ever more likely.

The more than 200m-thick tabular berg will not move very far, very fast in the short term. But it will need to be monitored. Currents and winds might eventually push it north of the Antarctic where it could become a hazard to shipping.

An infrared sensor on the American space agency’s Aqua satellite spied clear water in the rift between the shelf and the berg on Wednesday. The water is warmer relative to the surrounding ice and air – both of which are sub-zero.

“The rift was barely visible in these data in recent weeks, but the signature is so clear now that it must have opened considerably along its whole length,” explained Prof Adrian Luckman, whose Project Midas at Swansea University has followed the berg’s evolution most closely.

Project Midas:

A one trillion tonne iceberg – one of the biggest ever recorded – has calved away from the Larsen C Ice Shelf in Antarctica. The calving occurred sometime between Monday 10th July and Wednesday 12th July 2017, when a 5,800 square km section of Larsen C finally broke away. The iceberg, which is likely to be named A68, weighs more than a trillion tonnes.  Its volume is twice that of Lake Erie, one of the Great Lakes.

he final breakthrough was detected in data from NASA’s Aqua MODIS satellite instrument, which images in the thermal infrared at a resolution of 1km, and confirmed by NASA’s Suomi VIIRS instrument.

The development of the rift over the last year was monitored using data from the European Space Agency Sentinel-1 satellites – part of the European Copernicus Space Component. Sentinel-1 is a radar imaging system capable of acquiring images regardless of cloud cover, and throughout the current winter period of polar darkness.

The iceberg weighs more than a trillion tonnes (1,000,000,000,000 metric tonnes), but it was already floating before it calved away so has no immediate impact on sea level. The calving of this iceberg leaves the Larsen C Ice Shelf reduced in area by more than 12%, and the landscape of the Antarctic Peninsula changed forever.

Although the remaining ice shelf will continue naturally to regrow, Swansea researchers have previously shown that the new configuration is potentially less stable than it was prior to the rift.  There is a risk that Larsen C may eventually follow the example of its neighbour, Larsen B, which disintegrated in 2002 following a similar rift-induced calving event in 1995.

Below, more from British Antarctic Survey, and Al Jazeera:

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29 Responses to “Larsen C: One of the Biggest Bergs Ever just formed”

  1. indy222 Says:

    CNBC is reporting the break up, and saying it is NOT caused by climate change but is a “natural event”. No mention, of course, of the complete disintegration of Larsen A and Larsen B in the past 20 years and that they are not rebuilding. Wouldn’t want to upset the stock market investors, after all, with all the follderoll hair-on-fire climate alarmists.

    • Gingerbaker Says:

      “CNBC is reporting the break up, and saying it is NOT caused by climate change but is a “natural event”.”

      Can they make a persuasive argument that if we had not been burning carbon since 1840, that this iceberg would DEFINITELY have broken off? No… didn’t think so.

      It is absurd to think that any weather or “natural” event is not in some way affected by global warming. Just because there may not be definitive proof that any particular event is directly and wholly due to AGW, there is, by the very same token, an even better argument that you can not say the opposite is true.

      It is as if they might argue that since forest fires have occurred occasionally even in wet spells, that decades of abnormally hot and dry conditions can not be assumed to be responsible for an increase in forest fires.

      Ironically, the people who deny AGW are the same people who like to crow that “9-11 changed everything”. Well, guess what? An 125 ppm increase in [CO2] changes everything also.

    • redskylite Says:

      I’ve read reports from several scientists saying that the carving is perfectly natural and the event cannot be attributed to AGW/Climate change. Sure calving has happened before and will happen again with or without our help, but when would it have occurred without our push ? How come the world’s largest iceberg has launched on our watch. ?

      Scientists are very cautious and conservative as usual, the most convincing report I’ve read was from Minnesota’s local CBC today from a famed explorer who has actually traversed the glacier in question. He spoke in non-PC plain language and this guy I trust and listen to.

      While some experts believe this was a naturally-occurring event, others say it provides strong evidence that global warming is real.

      Among them is polar explorer and Minnesota native Will Steger.

      Twenty-seven years ago, Steger and his team of fellow explorers led a dog-sled expedition on the Larsen C ice shelf.

      They spent half a year in the icy region, where the average temperature was 30 below with 30 mph winds.

      “In 1989, 1990…the thought of these ice shelves breaking wasn’t even in the picture,” Steger said.

      http://minnesota.cbslocal.com/2017/07/13/will-steger-climate-change-iceberg/

      http://minnesota.cbslocal.com/2017/07/13/will-steger-climate-change-iceberg/

      • lesliegraham1 Says:

        “the world’s largest iceberg has launched”

        It’s not the world’s largest.
        Might not even be in the top ten.

        Not saying it is or isn’t at least partly due to AGW but facts are facts and it’s not the biggest.

        • redskylite Says:

          Thanks for the correction, I should have written one of the biggest or similar. In my enthusiasm I was careless and did not fact-check. Iceberg B15 from the Ross Ice Shelf which launched in 2000 was larger.

    • astrostevo Says:

      A natural event. Hmm.. So natural that it apparently has happened last since when .. ?

      That happens how often naturally and its purely co-incidence that it comes so (relatively) soon after the collapses of Larsen A & B ..

      Yeah, not quite sure how “natural” it really is..

  2. ubrew12 Says:

    What happens to a Roman arch that loses its keystone?
    Unrelated question… or is it?


  3. It’s just a little bit smaller than the county I live in, King County, Washington (Seattle is the county seat.)

  4. Tom Bates Says:

    An iceberg has formed, tear out your hair, throw the virgins in the volcano God in Hawaii, all is lost unless we give all out money to Hillary and Al Gore. Nevermind it was warmer in 1000 AD than today which means the ice was most likely less back than. http://www.livescience.com/39819-ancient-forest-thaws.html Never mind it has been warmer in the past for thousands of years. http://www.sciencedirect.com/science/article/pii/S0277379113004162
    Nevermind ice gains are greater than losses in antarctica https://www.nasa.gov/feature/goddard/nasa-study-mass-gains-of-antarctic-ice-sheet-greater-than-losses
    Never mind USA weather has been less if one counts hurricanes https://en.wikipedia.org/wiki/List_of_United_States_hurricanes
    http://www.cnsnews.com/news/article/barbara-hollingsworth/noaa-us-completes-record-breaking-11-years-without-major hurricanes or http://news.yahoo.com/insurer-2015-saw-lowest-natural-disaster-losses-6-100042419–finance.html
    never mind abrupt climate change is rather common, http://www.ncdc.noaa.gov/paleo/abrupt/data6.html

    • redskylite Says:

      What’s up with you ?. Nobody here is overreacting, except for you. You just add chaos and dumb obfuscation to the postings. People who regularly post here are interested if not concerned about the climate, whether natural of human influenced. Your whining and screaming will just get you stomach ulcers and I suggest you find a post you are more content with. Here you appear to be just another troll.


  5. Yeah indy222, the local rags in my part of the world all say because it was an ice sheet over water that an iceberg the size of Manhattan does not affect sea level. What they mean is that the volume of water in the ice won’t add net water, but they do not mention increased area of non-reflective sea absorbing sunlight, or greater exposure of the leading edge of the ice flow to relatively warmer water, etc. They do not ever seem to see the larger picture at all.


    • “… increased area of non-reflective sea absorbing sunlight, .. relatively warmer water, etc. They do not ever seem to see the larger picture at all. …”

      Yep, and all of us have either felt that directly or can imagine it, where mid December rays of sunlight manage to filter through cirrus clouds onto the one bit of strangely cracked and now suddenly open area of the Mississippi, raising the water temperature so dramatically that the stubborn ice jamb behind it rushes away like an avalanche, to sweep away St Cloud, Minneapolis, St Paul, and all points beyond.

      That’s a narrative that’ll sway millions of critical thinkers over to the AGW side, if only we could illustrate what this trigger point unleashes……. In the dead of winter. When it is -20C below freezing.

      • ubrew12 Says:

        The difference between science and denial is the former offers predictions and the latter offers sarcasm. John Mercer (Ohio State glaciologist) predicted in 1978 that Western Antarctica was uniquely threatened by global warming. He further predicted that we would know the breakup of that region was imminent when the ice shelves on the peninsula started breaking up, with the breakups moving progressively southward. Larsen A, the furthest north, collapsed in 1995. Larsen B collapsed in 2002. Now its Larsen C’s turn. Ice shelves that have been around for tens of thousands of years are temporary. On the other hand, climate denial ignorance is a permanent condition, like dementia.


        • The difference between science and denial (e.g. notions held by the creation science people) is the former examines all available data and analyzes all plausible science-based viewpoints, while the latter routinely and predictably rejects anything which undermines the preconceived (and thus anti-science) conclusion held by the science denier. In this global warming issue, never lose sight of who really are the climate change deniers: it’s those who demand a static climate where glaciers never melt or break into large icebergs, and when the worldwide temperature average never changes from an arbitrarily-selected level from 150 or so years ago.

          • ubrew12 Says:

            I took a look at the last 220 centuries of global temperature, and calculated my best estimate of the change per century for each of those centuries. This was most accurate over the last 20 centuries, because I was using the Pages-2k tree ring database, which is good each year or decade. For the 200 centuries before that I took thousand year intervals and imposed the century by century standard deviation I got from the Pages-2k system to estimate the true variability out to 220 centuries ago. I got a normal distribution (bell curve) of temperature change per century, with a mean of 0.014 C/century (0.014*220 centuries = 3 C, i.e. in the last 22,000 years Earth climbed out of a glacial period), and a standard deviation of 0.077 C/century. Hence, any temperature change greater than 0.24 C/century is not natural (0.24 = 3*.077, its the 3-sigma, or 99% confidence limit for that bell curve). Climate change in the 20th century was 0.78 C/century. If the last 25 years holds for the next 75 years, then 21st century warming will be 2.2 C/century, or about TEN TIMES the rate that would disqualify it as ‘natural’. Modern climate change is not natural, and it requires a blinding level of denial to think it is.

          • andrewfez Says:

            ..and when you look at the last 20 centuries quantized to such, the sea level rise curve is also a hockey stick.

      • andrewfez Says:

        Polar sea ice + snow, especially in the Arctic, has the highest albedo of any of the Earth’s surfaces, clocking in at 0.5 to 0.7 just for the ice and up to 0.9 for ice + snow. Open sea water has an albedo of like 0.06.

        The energy coming into the Earth system is approximately 1350W/m^2 * (1 – albedo) * piR^2 (i.e. the Earth’s shadow in space) and average albedo is something like 0.33 so you can get a feel for what’s at stake when that starts to drop.

        There is a lot of energy being delivered even in the winter time, so much so that you can heat a passive solar house up pretty good with just the sun, to the point you have to open some windows to drop the temp back down to something comfortable.

  6. vierotchka Says:

    I’m glad to see that you quoted the BBC article I posted a link to yesterday (http://www.bbc.com/news/science-environment-40321674) in response to Astrostevo on https://climatecrocks.com/2017/06/29/hours-days-or-weeks/

    (How long before dumboldguy will respond to this post with his ludicrous insults and attacks, I wonder…)

    • dumboldguy Says:

      Since you asked, here I am, not with a “ludicrous attack”, but with some cogent commentary—-you know, that stuff you seem to be incapable of dealing with?.

      Your attempt to “play nice” with that unneeded comment on the other thread yesterday and to childishly seek some sort of credit for doing it here does not change the fact that you do not visit Crock to contribute in any meaningful way to the discussion of AGW. Your real purpose here is to work as a Russian troll and Whore for Putin, undermine the USA and the West, and push for greater use of fossil fuels to keep Russia afloat.

      Visitors to the “hours-days-weeks” thread will find that you were directly challenged to comment on the TRUTHS that are coming out about collusion between the Trumpistas and the Russians and that you have been COMPLETELY SILENT. After saying “didn’t happen—it’s a lie—-ridiculous” uncounted times on many threads, you have had your baggy Russian knickers not just pulled down but pulled off and thrown to the wind.

      Give it up, Vera (but be consistently stupid and DO bore us with another moronic gif before you go).

      • vierotchka Says:

        Your imaginative projections about me are completely off target, as always.

        If you honestly believe that the very intelligent Putin wanted the totally unstable, unpreditable and rather insane psychopath Trump to have his finger on the nuclear button rather than Hillary Clinton, not only are you much dumber than I credited you for, you also are

        Better the devil you know and are used to than the insane demon.

      • vierotchka Says:

        Had Putin and Russia really intervened in the US elections, Hillary Clinton would be the President today, not Trump.

        You are as totally hopeless and clueless with regard to politics as you are brilliant with regard to climate change, so stick to what you actually know and understand instead of regularly make a total fool of yourself in your responses to me.

        • vierotchka Says:

          Ooops – making, not make, of course.

        • ubrew12 Says:

          “Had Putin… really intervened in the US elections, Hillary Clinton would be the President today” I don’t believe for a second that you actually believe that. Nobody hacks the DNC headquarters and releases their donor list with an eye toward getting Clinton elected. The evidence for Putin interfering in our democracy for Trump is overwhelming. In time, Mr Putin, and Russia, are going to have to pay for that interference.

  7. mboli Says:

    Meanwhile real estate investors and developers have made plans to tow it to northern Sweden, where it will be sited near the Ice Hotel. They will carve out Ice retail shopping with Ice condominiums.
    A whole ice burg, so to speak.
    The small investors who buy the condominiums as investment properties will be told their investments are safe because climate change is just fake alarmism. Or something.

  8. grindupbaker Says:

    Based on the fracture of the Larsen C ice shelf first being noticed in November 2010, its extent at that time and its rate of growth the few years following, I suggest the possibility that the fracture of the Larsen C ice shelf might have been caused by the Indian Ocean tsunami 26 December 2004 following sea bed earthquake. “The tsunami also reached Antarctica, where tidal gauges at Japan’s Showa Base recorded oscillations of up to a metre with disturbances lasting a couple of days”. If I take ice tensile strength at 3,000,000 newtons per square metre and assume ice shelf is 300m thick along the fracture (because it’s said to be average 200m thick) then I roughly compute the fracturing force exerted on the lower face of the ice shelf at the fracture location from 1 metre of SLR would be 38x that required to fracture it if ice was perfectly brittle. Of course, ice has some ductility & malleability (not perfectly brittle) and tides there are of order 1m to 1.7m, same as that tsunami or somewhat higher, so the ice shelf could not survive tides if it was perfectly brittle. Davis tide table indicates typically 14 hours for the tide to rise 1m to 1.7m but perhaps the far more rapid impact force of a tsunami SLR (over a few minutes I assume) would not give the ice shelf sufficient time to respond elastically throughout its length and it fractured along its weakest line on the lower face due to the torque exerted. Would open a fracture 7 mm wide at 42 km back if the ice did not yield anywhere except at the fracture so, for example, if the ice bent 90% of the required amount to relieve stress throughout its length then it would open a fracture 0.7 mm wide. Would need structural analysis to figure it out properly.


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