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Greenland's Fastest Glacier Sets New Speed Record
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."
the glacier will break Mach 1 by 2016 when Hillary is president and Al Gore is secretary of state.
You know I don't really care about the number of humans the impeding environmental crisis will kill off, the more the better, as long as its not me of course, and it will take at least 50 years, by which time I will be dragged to my grave by my fat ass. In all probability it will be some brown nobody that cooks his food over a dung fire in Asstonia, and who gives a fuck about that ? What concerns me more is the sterile wasteland the survivors will create. I mean its nice to "conserve" some splatter of greenery somewhere out of town siting in front of your TV in your underpants, drinking craft beer, but I'll wager not much will stop you bulldozing that shit down to feed your starving kids.
Wrong question. The question is how far sea level is going to rise over your lifetime due to a multitude of causes. Then when you know that, the question is how much you will have to pay (in taxes, prices, and risk) to deal with the consequences.
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Seriously, you think pressure for *annual snowfall* makes a dramatic difference in the speed of the Jakobshavn glacier. this Jakobshavn glacier. The one that's two kilometers thick.
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And those who use the word "Denier" are more credible?
It proves Greenland is warming. The *global* pattern proves that the globe is warming.
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Snowfall needs moist air. Warmer air holds more moisture. Increased snowfall is well in the scope of what's been thought to happen. There really doesn't need to be any alarmist campaign; simple scientific observation of the amplified greenhouse effect is enough.
I don't think neither "alarmist" nor "denier" are very helpful. Let's ask the climate scientists, in stead. Once again:
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].
Gosh, thanks. That must be why the other ships call me Meatfucker -- GCU Grey Area (Eccentric)
I did a little searching and found a paper from 2011 [pdf] 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 has been well documented by the GRACE satellites. See the Total Ice Mass section of the Arctic Report Card: Update for 2013 for details.
Greenland has experienced (like Antarctica) some very heavy snowfalls in the past few years, which increases the thickness of the glaciers. Glacial flow is fairly well understood, as the glacier gets thicker it causes faster movement.
An observant person might note that the fact that is now snowing in places where it was previously too cold to snow is actually an indication of change, not an argument against it.
The calving of large glaciers is often touted by [scientists] as proof of their claims, but this phenomenon does not actually support the [scientists] position at all.
You are mistaken. Climatologists don't claim that glacial calving is proof of AGW - this proof lies in the observations and theories of Tyndall, Fourier, Arrhenius et al.
I'm not sure what it is about Climatology that makes people think that ignorance can substitute for knowledge. Does this muddled thinking work, say, when you go to the bank "I'm skeptical of alarmist bankers claims that my account is overdrawn"?
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), 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.
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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.
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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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It's not so simple as "10 cm/decade doesn't seem like much".
Imagine storm surges laid out on a bell curve, with height above mean high tide as the X axis. When you chose how close to build to the waterline, and the protections you put in, you probably wouldn't draw the line where you'd get one flood every thousand years. You might decide you can live with one flood every ten years. But shift the mean high tide by 20 cm over two decades, and that once a decade flood might happen eight or ten times a decade.
There's often a sharp line between a near miss and a disaster. A one foot rise over thirty years (roughly correponds to 1m/century) means that a seawall or levee that would have held back the flood get overtopped. A one foot rise means a place that never got flooded before could be in harms way. Some of the levees that failed in Katrina were overtopped by only a matter of inches. Others were overtopped by ten feet, but that's a different issue.
And in a lot of the world, the floodplain isn't chosen because it's a nice place to live. Bengladeshi subsistence farmers don't locate in low areas because of the beaches, but because that's the only land they can afford. These are people with very low levels of material consumption. They don't get much of the share of benefit from the carbon added to the atmosphere, but they bear a disproportionate share of the costs.
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Fourier's discovery that the Earth was warmer than it should be given its size and distance from the Sun was a major step forward in geoscience.. That he may not have had the mechanism right in no way detracts from the importance of that insight.
The glacier is thinning because its surging. Another way of looking at it is that the glacier is growing in length rapidly, but then that sounds somehow less scary doesn't it?
Yes, intuitively one would think that if a glacier speeds up, it must be growing more quickly. But the world is a complex place, so we should be vary of our intuition. Thankfully people have actually measured the lenght of the glacier, so we con't have to guess:
As the Arctic region warms, Greenland’s glaciers have been thinning and calving icebergs farther and farther inland. This means that even though the glacier is flowing toward the coast and carrying more ice into the ocean, its calving front is actually retreating. In 2012 and 2013, Jakobshavn’s front retreated around 0.6 miles (1 km) each year compared to its position the previous summer.
Sometimes it pays to read TFA!
"Sometimes it pays to read TFA!"
don't hold your breath on deniers/religionists reading and believing facts/evidence
"The hands that help are better far than lips that pray." - Robert Ingersoll (1833-1899)
OK, I cherry picked the data. Why do you use the 1950-1980 baseline, why not something earlier and longer for the baseline? Oh - and you never answered where you get your data from...
Browsing at +1 - no ACs, I ignore their posts. So refreshing!
It doesn't matter what baseline you use for X and Y if you want to answer "how much greater is X than Y?" When I calculate "X - Y", the choice of baseline cancels out. It doesn't matter if I do the calculation in celsius or kelvin; or if I choose 1900-1999 as a baseline or 1950-1980. The answer to the question "how much hotter was 2005 than 1995?" is still going to be 0.2C.
As for the choice of 1995 as a baseline, it was *your* idea to use a year that set a record for high temperature and ask, "has it got warmer since then?" and surprisingly, the answer turns out to be "yes". That's very different than taking ten or more years as your baseline, which cancels out the effect of unusually hot or unusually cool years impartially.
As for the source of my data, here you go.
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