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Science

Greenland's Fastest Glacier Sets New Speed Record 136

Posted by Soulskill
from the zoom-zoom dept.
vinces99 writes "The latest observations of Jakobshavn Glacier show that Greenland's largest glacier is moving ice from land into the ocean at a speed that appears to be the fastest ever recorded. Researchers from the University of Washington and the German Space Agency measured the speed of the glacier in 2012 and 2013. The results were published Feb. 3 in The Cryosphere, an open access journal of the European Geosciences Union. Jakobshavn Glacier, which is widely believed to be the glacier that produced the large iceberg that sank the Titanic in 1912, drains the Greenland ice sheet into a deep-ocean fjord on the west coast of the island. This speedup of Jakobshavn means that the glacier is adding more and more ice to the ocean, contributing to sea-level rise. 'We are now seeing summer speeds more than four times what they were in the 1990s, on a glacier which at that time was believed to be one of the fastest, if not the fastest, glacier in Greenland,' said lead author Ian Joughin, a glaciologist at the UW's Polar Science Center. The new observations show that in summer of 2012 the glacier reached a record speed of more than 10 miles (17 km) per year, or more than 150 feet (46 m) per day. These appear to be the fastest flow rates recorded for any glacier or ice stream in Greenland or Antarctica, researchers said."
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Greenland's Fastest Glacier Sets New Speed Record

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  • by erikkemperman (252014) on Wednesday February 05, 2014 @02:26AM (#46159613)

    I don't think neither "alarmist" nor "denier" are very helpful. Let's ask the climate scientists, in stead. Once again [wikipedia.org]:

    In the scientific literature, there is a strong consensus that global surface temperatures have increased in recent decades and that the trend is caused primarily by human-induced emissions of greenhouse gases.[2][3][4] No scientific body of national or international standing disagrees with this view,[5] though a few organizations hold non-committal positions.[6] Disputes over the key scientific facts of global warming are now more prevalent in the popular media than in the scientific literature, where such issues are treated as resolved, and more in the United States than globally[7][8].

  • by riverat1 (1048260) on Wednesday February 05, 2014 @02:33AM (#46159649)

    I did a little searching and found a paper from 2011 [pdf] [science.uu.nl] that addresses Jakobshavn specifically. It has this to say:

    3.3. Jakobshavn Isbroe

    Jakobshavn Isbroe was losing 8 Gt a1 of mass per year in 2000 (Figure 2). This rate increased over the following years to near 25 Gt a1 by the end of 2002. The loss rate then stabilized and declined back under 20 Gt a1 until 2006, when it increased to 33 Gt a1, reaching 34 Gt a1 by the end of 2007. Subsequently, the annual loss rate has fluctuated between 25 and 33 Gt a1. In total the glacier lost 321 ± 12 Gt by the end of 2010, equivalent to a basin!wide thinning of 3.5 m, with 2/3 of this loss occurring since June of 2005 (Figure 3). The 85 km2 of retreat accounts for nearly 20% of this loss. The rate of discharge is now such that the glacier is losing mass nearly throughout the year. As previously reported [Joughin et al., 2008a, 2008c; Luckman and Murray, 2005], annual oscillations in speed of ±20%, with a peak in June/July, correlated with seasonal retreat and advance of the ice front, become increasingly pronounced at the location of the fluxgate after 2005 (Figure S7). Seasonal oscillations in speed, SMB and front position cause annual fluctuations in mass of up to 50 Gt.

    Of the other two glaciers reported on in the paper Helheim gained 17 +/- 13 Gt and Kangerdlugssuaq lost 152 +/- 10 Gt compared to Jakobshavn's 321 +/- 12 Gt in the 11 year period studied. Those are the three largest outlet glaciers in Greenland.

    More generally the ice mass loss on Greenland [noaa.gov] has been well documented by the GRACE satellites. See the Total Ice Mass section of the Arctic Report Card: Update for 2013 [noaa.gov] for details.

  • by hey! (33014) on Wednesday February 05, 2014 @03:01AM (#46159769) Homepage Journal

    Fortunately, we don't have to deal in "suggestions". People have actually *gone* to the glacier and taken measurements. It is thinning dramatically since 1997 [1]. Nor do we have to deal in suggestions about the temperature of Greenland, because people have been measuring that too. It is warming, dramatically on the western coast, somewhat less so on the eastern. [2]

    The glacier in question, by the way, is considerably less than 100 km long (as you an readily see [goo.gl]), so the interior doesn't enter into the question of what this glacier is doing at all. However if you're interested, ice core data shows that the interior has warmed over the past several decades. [3]

    I can certainly buy the argument that this event doesn't prove *global* warming, because it doesn't. But the argument that it proves *local cooling* doesn't hold water, because it we know *from measurements* that there hasn't been local cooling, especially in southwestern Greenland where this glacier is *entirely* located.

    --- Citations ---
    1: Liu, Lin, John Wahr, Ian Howat, Shfaqat Abbas Khan, Ian Joughin, and Masato Furuya. "Constraining ice mass loss from Jakobshavn Isbræ (Greenland) using InSARmeasured crustal uplift." Geophysical Journal International 188, no. 3 (2012): 994-1006.

    2: Hanna, Edward, Sebastian H. Mernild, John Cappelen, and Konrad Steffen. "Recent warming in Greenland in a long-term instrumental (1881–2012) climatic context: I. Evaluation of surface air temperature records." Environmental Research Letters 7, no. 4 (2012): 045404.

    3: Muto, Atsuhiro, Ted A. Scambos, Konrad Steffen, Andrew G. Slater, and Gary D. Clow. "Recent surface temperature trends in the interior of East Antarctica from borehole firn temperature measurements and geophysical inverse methods." Geophysical Research Letters 38, no. 15 (2011): L15502.

  • by hey! (33014) on Wednesday February 05, 2014 @03:12AM (#46159817) Homepage Journal

    What you're talking about is 1.2 meters of new ice on top of *two kilometers* of primordial ice. If we scaled the ice sheet to 2 meters tall, the extra accumulation would be roughly the thickness of a piece of paper.

    In any case, you're confusing the vast, 400,000 year-old interior ice sheet with a coastal glacier. It makes no difference that the interior ice sheet has thickened very slightly because measurements of the *glacier in question* show that *it* is thinning.

  • by hey! (33014) on Wednesday February 05, 2014 @03:32AM (#46159897) Homepage Journal

    You realize 1995 set a record for hottest year ever on record? So you've cherry picked a particularly hot year as your baseline (or somebody dishonest picked it for you). That's Ok, because that record has been exceeded ten times since then, starting with 1998 which was *also* the hottest year on record.

    1995 was 0.4C hotter than the 20thC average. 2005 was 0.6C hotter than the baseline, and 2010 was just a smidgen hotter than 2005. So you could answer 0.2C to your question. But it's a lousy question, not just because it starts from a cherry-picked baseline, but because there's so much variation between years.

    A better question is "How much hotter were the 00's hotter than the 90's?" The 1990s where 0.313 C hotter than the 1950-1980 baseline. The 00s were 0.513 C hotter than the baseline. So again the answer to the question is 0.2C.

    Each of the past three decades set a record for the hottest on record.

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