Why Southeast Greenland's glaciers have slown down since 2005

By: Dr. Jeff Masters , 3:57 PM GMT on December 15, 2009

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I'm in San Francisco for the annual meeting of the American Geophysical Union, the world's largest gathering of climate scientists. I saw ten or so great talks yesterday (and five really boring ones!) Here's a summary of the the most interesting talk I heard yesterday:

If you plan on owning ocean front property after the year 2050, you should pay close attention to the glaciers In Greenland. Greenland holds enough ice to raise global sea level by over 20 feet (6.5 meters), should its ice cap completely disintegrate--though such an event would likely take centuries to occur. Still, should the climate warm 2°C or more this century, partial melting of the Greenland Ice Sheet could readily raise global sea level by a meter or more by 2100. That's why scientists reacted with concern during 2003 - 2005, when all of the glaciers in southeastern Greenland accelerated in synchrony to speeds 30% to 210% faster than they had flowed in 1996. As they sped up, the glaciers began dumping huge amounts of ice into the ocean off the coast of southeast Greenland, more than doubling Greenland's contribution to global sea rise, to .57 mm/year. Would the glaciers keep accelerating, bringing about an increasing disintegration of the Greenland Ice Sheet? Nobody knew, since computer models of glacial dynamics were (and still are) in a primitive state.


Figure 1. Helheim Glacier in southeast Greenland, in three images captured in 2004, 2005, and 2006. The glacier accelerated significantly in 2005, and the face of the glacier retreated 5 km inland (middle frame) compared to 2004. However, by the summer of 2006, the acceleration ceased, the the glacier returned back to its 2004 position. Image credit: Ian Howat, University of Washington.

Well, it turned out that 2005 was the peak of the glacial acceleration event. The glaciers in southeast Greenland have returned to where they were eight or nine years ago--still causing a net loss of mass that is raising global sea level, but not as fast as in 2003 - 2005. In a talk titled, "Ocean regulation of glacier dynamics in south-east Greenland and implication for ice sheet mass changes", Tavi Murray and colleagues from the UK's Swansea University presented a plausible theory for why this strange synchronous speed-up and slow-down occurred. Using satellite, aircraft, and surface observations, the researchers found that air temperatures in the region did not vary much over 2003 - 2005 (Figure 2). Thus, a major increase in temperature could be ruled out as the cause of the glacier surge. However, study of the ocean temperatures near the coast revealed strong clues that ocean currents were responsible for the surge.

Figure 2. Ocean currents off the east coast of Greenland feature the cold East Greenland Coastal Current flowing north to south (white arrows) and the warm Irminger Current flowing south to north (red arrows). Image credit: Arctic Climate Impact Assessment.

Ordinarily, the southeast coast of Greenland features a cold water current flowing north to south, called the East Greenland Coastal Current (EGCC). Much of the cold water for this current is supplied by melting of the 14 glaciers in southeast Greenland that empty into the sea (two of these glaciers, Kangerdlugssuaq and Helheim, represent 35% of east Greenland's total glacial discharge). A few hundred kilometers offshore, a warm water current called the Irminger Current flows the opposite direction, bringing warm water from the North Atlantic northward. In 2003, it happened that weather conditions over Greenland brought an unusually low amount of run-off of precipitation. With little new mass pushing the glaciers seaward, the glaciers responded by greatly reducing the amount of ice they dumped into the ocean by the shore. As a result, the East Greenland Coastal Current slowed down and warmed, which allowed the warm Irminger Current to advance towards the coast, warming the coastal waters even more. All that warm water near the coast began melting the glaciers where they reached the sea, causing the glaciers all along the southeast coast of Greenland to accelerate and rapidly thin between 2003 - 2005. By 2006, the thinning glaciers had dumped so much new ice into the ocean near the coast that the waters cooled and the East Greenland Coastal Current re-established itself. This cooled the glaciers at their marine termination points and slowed down the glacial surge, putting the glaciers back where they had been before 2003. This is a classic example of a negative feedback process--a change in weather conditions which generates a response, but the response creates conditions that tend to dampen the response.


Figure 3. Average temperatures for the only station in southeast Greenland with a century-long temperature record, Angmagssalik (called Ammassalik on the map in Figure 2). Temperatures in southeast Greenland during the 1930s and 1940s were similar to today's temperatures, suggesting that glacial surges like we witnessed in 2005 may have also occurred in the 1930s and 1940s, before we had monitoring capability. Image credit: NASA Goddard.

Commentary
As I commented in my previous post, Arctic sea ice loss appears to have created a new atmospheric circulation pattern that brings more warm air in the Arctic, creating a positive feedback loop that causes even more sea ice loss. This positive feedback loop was a bad news surprise that our climate models did not predict. Now we have evidence of a good news surprise that no model predicted--a negative feedback loop that acts to keep the southeast portion of Greenland's Ice Sheet from runaway glacial acceleration. We can expect many more surprises--good and bad--over the coming decades, as our climate responds to the huge shove human activities are giving it.

Ricky Rood in Copenhagen
Our Climate Change expert, Dr. Ricky Rood, is in Copenhagen for the COP15 climate change treaty negotiations. His latest post, called Have you no sense of decency, sir, at long last? makes for very interesting reading on how the U.S. is "wasting its intellect and time on disruptions designed to play to people at home".

Next post
I'll have another post from the AGU meeting Thursday or Friday this week.

Jeff Masters

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1163. amd
good precipitation amounts from Philly to Washington DC, and definitely into the Va Beach Area.

Assuming that much of this, especially north of central virginia, is all snow, there looks to be some nice totals from richmond to philly.

Sorry NYC and Boston.

Drak, looks like you nailed the jet stream not allowing the storm to complete the trek up the east coast. Good call at this point.

edit: forgot to add the gfs total precip forecast up to Sunday Night:

00Z GFS Precip up to Sunday Night
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i had rasin bran and lousiana hot sauce

Isn't Metamucil available in NC?
Member Since: August 19, 2008 Posts: 32 Comments: 1918
Quoting AwakeInMaryland:

Oh for Pete's sakes. The four of us should get together sometime over angelfood & devilsfood cakes and coffee!


Member Since: August 22, 2008 Posts: 12 Comments: 6010
1160. DanM6
While I do not find Dr. Master's analysis beyond reproach, and will not hesitate when I differ with his statistical analysis, I see nothing wrong with posting things on his blog. Granted, it's nominally a tropical weather blog, but I don't think that discussing non-tropical weather and climate are inappropriate. The realistic alternative would be to discuss the tropical weather in the southern hemisphere exclusively....as well as the occasional prediction of next year's season in the northern hemisphere.

I think it particularly useful to see the post on the negative feedback cycle with glacial movement in Greenland. That's a nice bit of science that will add to our understanding and will be put in climate models as it is solidified....or not if it's falsified later. (I'd guess the former is more likely, but its still new work...and not yet put through the wringer).

I think scientists have a right to political positions, I have my own. But, I try to be clear when I'm wearing my scientist hat and when I'm wearing my concerned citizen's hat. A good scientist will publish work that will decrease the liklyhood that what he wants to happen will happen because it is an accurate analysis. Scientists get into trouble when they pick and choose data and theories to match their politics.

The fact that Dr. Masters has given reviews of symposium presentations that indicate greater damage from global warming than some suspect and reviews that indicate lesser damage than others expect indicates to me that he is primarily trying to present the science. Good for him. I don't see anything wrong with that at all.
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Quoting Drakoen:
The NAM shows a thick band of snow south of the Mason-Dixon line into Virgina and Maryland before the system exits:



drak how confident should we be in these model runs? 0z are the most reliable right?
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1158. Grothar
Quoting CatastrophicDL:

I wasn't saying the viking wore horns, I was making a statement about where perhaps the idea may have come from. I agree the history about the Druids is very weak. My history professor from France who was educated at the Sorbonne and specializes in Frankish history said from what is known about the Druids, they most likely did wear hoods or helmets with animal parts on them. Anyway just something someone else brought up.


No problem, it is a running joke with a few of us on here. Did you go to La Sorbonne? I lived on the Quai de La Tournelle when I studied there.
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Quoting Drakoen:
The NAM shows a thick band of snow south of the Mason-Dixon line into Virgina and Maryland before the system exits:



Here is the latest loop 00Z, -0-HRS-108 HRS GFS, 2M Temps, 10M Winds (SURFACE LEVEL) Java Loop..

Link
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1156. Drakoen
Quoting StSimonsIslandGAGuy:
Hmmm some wild snow accumulations in NC maybe like this?



Definitely possible especially in the western zones.
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Quoting PcolaDan:


LOL Now I know what I liked about you! How the two of you doing, both of us here are just great. :)

Oh for Pete's sakes. The four of us should get together sometime over angelfood & devilsfood cakes and coffee!
Member Since: August 19, 2008 Posts: 32 Comments: 1918
Did you guys see this about the sea bridge? It can withstand some pretty good winds, but how quickly would storm surge destroy it? Link
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1152. Drakoen
The NAM shows a thick band of snow south of the Mason-Dixon line into Virgina and Maryland before the system exits:

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off topic,, sorry,, mama brought neckbone stew, dad had okra and lima beans,, i had rasin bran and lousiana hot sauce,, its in a pot, cookin for the snow storm
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1150. Drakoen
Quoting VAbeachhurricanes:
Drak basically nailed this run 6 hours ago!


:)
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Drak basically nailed this run 6 hours ago!
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Quoting Grothar:


The Vikings did not wear horns on their helmets and neither did the Druids. There are pictures of modern times showing Vikings with helmets, but there is nothing in history to suggest they did. Having been raised in Scandinavia and taught history there, I know that much. The Druids wore certain fox and birds parts on their helmets and perhaps some may even used elk horn, which was for specific rituals of the pre-Christian era. Actually very little is know of the early Druids, since Rome erased most traces of them.

I wasn't saying the viking wore horns, I was making a statement about where perhaps the idea may have come from. I agree the history about the Druids is very weak. My history professor from France who was educated at the Sorbonne and specializes in Frankish history said from what is known about the Druids, they most likely did wear hoods or helmets with animal parts on them. Anyway just something someone else brought up.
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1147. Drakoen
Quoting VAbeachhurricanes:


WOW that would be amazing... im lovin this run!


That would give you guys some heavy snow accumulations.
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Quoting AwakeInMaryland:
1102. Dan -- that's easy; they both are!
Sun Sign: Gemini
But not quite like "I Dream of Jeannie", Master! Blink Blink.


LOL Now I know what I liked about you! How the two of you doing, both of us here are just great. :)
Member Since: August 22, 2008 Posts: 12 Comments: 6010
Quoting StSimonsIslandGAGuy:
But does the devil wear Prada?

Oh, dunno', personally, I prefer Chanel.
---------------------------------------

I have looked and looked, and I swear I can't see the devil in the details of that Canadian note. Either my soul is too pure...or you have to be Canadian. Is Orca still here?

What did Grothar trip over? Hooves or tail?

Oh, snow this weekend! Hell (aka DC) IS freezing over!
Member Since: August 19, 2008 Posts: 32 Comments: 1918


WOW that would be amazing... im lovin this run!
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Quoting StSimonsIslandGAGuy:
But does the devil wear Prada?


Probably so after he got kicked out of Georgia.

Member Since: August 22, 2008 Posts: 12 Comments: 6010
1142. Grothar
Did Vikings Wear Horned Helmets?
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The Myth
Viking warriors wore horned or winged helmets.
The Truth
There is no evidence, archaeological or otherwise, that Viking warriors wore any type of horns or wings on their helmets. What we do have is one single piece of evidence, the ninth century Oseberg tapestry, suggesting a rare ceremonial use (the relevant figure on the tapestry may even be that of a god, rather than representative of real Vikings) and plenty of evidence for plain conical/domed helmets made mainly of leather.

Horns, Wings and Wagner
I’m sure we’ve all seem them, pictures of large, hairy men with horns sticking proudly out of their helmets as they rush to rape and pillage. It’s so common it must be true surely? Well, no. Years of excavations, coupled with studies of images, have yielded no evidence for the common use of horned or winged Viking warrior helmets. So where has the idea come from? Roman and Greek writers referred to northerners who wore horns, wings and antlers, amongst other things, on their helmets. Like much contemporary writing about anyone non-Greek or Roman there appears to have already been a distortion here, with archaeology suggesting that while this horned headgear did exist, it was largely for ceremonial purposes and had largely faded out by the time of the Vikings, often considered to have started in the late eight century. This was unknown to the writers and artists of the early modern era, who began referencing the ancient authors, making misinformed jumps and depicting Viking warriors, en masse, with horns. This image grew in popularity until it was taken on by other forms of art and passed into common knowledge. The temporary mis-identification of a Bronze Age carving in Sweden with a horned helmet as Viking didn’t help matters, although this was corrected in 1874.
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1141. Grothar
From Wiki:

Helmet

Helmet from chieftain's grave, 10th cent. NorwayToday there is only one known example of a Viking helmet in existence.[1] This Viking helmet was made of iron and was in the shape of a rounded or peaked cap made from four plates after the spangenhelm pattern, and was excavated from Gjermundbu, Norway, and dated to the 10th century. Gjermundbu is located in Haugsbygda, a village in Ringerike municipality, northeast of the center of Hønefoss, in Buskerud, Norway. This helmet has a rounded cap and has a "spectacle" guard around the eyes and nose, in addition to a possible mail aventail. The eyeguard in particular suggests a close affinity with the earlier Vendel period helmets. From runestones and other illustrations, we know the Vikings also wore simpler helmets, often peaked caps with a simple noseguard. It is unlikely that any Viking helmets had horns or wings mounted on them, but illustrations from the 19th Century popularized this representation.[2]
[edit] Mail
Once again, only a single fragmented but possibly complete mail shirt has been excavated in Scandinavia, from the same site as the helmet - Gjermundbu in Haugsbygda. Scandinavian Viking age burial customs seems to not favour burial with helmet or mail armour, in contrast to earlier extensive armour burials in Swedish Valsgärde. The mail shirt is currently interpreted as elbow-and-knee length. Probably worn over thick clothing, a mail shirt protects the wearer from being cut, but offers little protection from blunt trauma. Mail was very expensive in early medieval Europe, and would likely have been worn by men of status and wealth. It was almost certainly the "four-in-one" type, where four solid (punched) rings are connected by a single riveted ring. Mail armour of this type may also be known as a byrnie or brynja.

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Quoting pinehurstnc:
yall are just to kind,, to answer , an almost wannabe met, btw ,, greg fishel.. is downplaying this event .like it will never happen,, and he is the biggest snowking in nc


The link below goes to a local meteorologist Allan Huffman. He is an ACTUAL meteorologist, w/10 years experience, check out this link :0)

Link
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1102. Dan -- that's easy; they both are!
Sun Sign: Gemini
But not quite like "I Dream of Jeannie", Master! Blink Blink.
Member Since: August 19, 2008 Posts: 32 Comments: 1918
1138. Grothar
Quoting CatastrophicDL:

The horn helmets


The Vikings did not wear horns on their helmets and neither did the Druids. There are pictures of modern times showing Vikings with helmets, but there is nothing in history to suggest they did. Having been raised in Scandinavia and taught history there, I know that much. The Druids wore certain fox and birds parts on their helmets and perhaps some may even used elk horn, which was for specific rituals of the pre-Christian era. Actually very little is know of the early Druids, since Rome erased most traces of them.
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1137. xcool
VAbeachhurricanes anytime!
Member Since: September 26, 2009 Posts: 2 Comments: 15684
Quoting VAbeachhurricanes:



i know youve done it a billion times, but can you link it :)


The link is below, it will take about 1 hr before the complete run is ready!! They're on
42 HRS right now!
Link
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yall are just to kind,, to answer , an almost wannabe met, btw ,, greg fishel.. is downplaying this event .like it will never happen,, and he is the biggest snowking in nc
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Quoting Bordonaro:
00Z 12-17-09 GFS Run Update has started!!



i know youve done it a billion times, but can you link it :)
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Canadian Devil's Head $2 Note~ Close-Up
Member Since: August 19, 2008 Posts: 32 Comments: 1918
I know you guys all like sports...
sad news
Bengals WR in Critical Condition
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1130. chawk
I truly miss Dr Masters current weather discussions, They are why I logged on to this site years ago and always looked forward to his view of what we could expect here in Florida. I do not know half of what most of you know about meteorology, but I do know the difference between a scientist and a politician. Hopefully, good ole mother nature will put this AGW conflict to rest either way soon.
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Quoting Orcasystems:


Mine doesn't fall very far.. the horns hold it up :)


For those that haven't seen one the nose of the devil is just to the right of the Queen's ear. Then take it from there.




Member Since: August 19, 2008 Posts: 32 Comments: 1918
Quoting Grothar:


What may I ask to the Druids have to do with Vikings?

The horn helmets
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1127. Grothar
Quoting CatastrophicDL:

The Druids used horn helmets and worshiped animalistic type diety.


What may I ask to the Druids have to do with Vikings?
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00Z 12-17-09 GFS Run Update has started!!
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Quoting Grothar:


But you do them so fast and so appropriately!!!
That, I am sorry to say, IS impressive.


LOL Well, I'm easily amused. It's all Orca's fault anyway.

add edit:It's also an exercise for my short term memory. "Where did I see that thing???"
Member Since: August 22, 2008 Posts: 12 Comments: 6010
Quoting quasigeostropic:
Now we have evidence of a good news surprise that no model predicted--a negative feedback loop that acts to keep the southeast portion of Greenland's Ice Sheet from runaway glacial acceleration. We can expect many more surprises--good and bad--over the coming decades, as our climate responds to the huge shove human activities are giving it.

Nothing extraordinary there...The earth has ALWAYS found ways to counterbalance the imbalances in nature....Newton's 3rd law of motion...The fact this circulation took the climate models off guard, shows/proves they are insufficient enough to grasp such processes, thus making the confidence level of climate models MUCH lower than the AGW crowd makes them out to be...But of course, melting ice caps dont prove man did it..It only proves that certain variables are making ice melt in certain ways....

+1
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Quoting atmoaggie:

Viking don't have horns. I was educated on that a day or so ago. Not sure whom it was that blessed us with that knowledge.
(And the Minnesota NFL team apparently has it wrong)

The Druids used horn helmets and worshiped animalistic type diety.
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1122. Grothar
Quoting PcolaDan:


Timing is everything. lol


But you do them so fast and so appropriately!!!
That, I am sorry to say, IS impressive.
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Now we have evidence of a good news surprise that no model predicted--a negative feedback loop that acts to keep the southeast portion of Greenland's Ice Sheet from runaway glacial acceleration. We can expect many more surprises--good and bad--over the coming decades, as our climate responds to the huge shove human activities are giving it.

Nothing extraordinary there...The earth has ALWAYS found ways to counterbalance the imbalances in nature....Newton's 3rd law of motion...The fact this circulation took the climate models off guard, shows/proves they are insufficient enough to grasp such processes, thus making the confidence level of climate models MUCH lower than the AGW crowd makes them out to be...But of course, melting ice caps dont prove man did it..It only proves that certain variables are making ice melt in certain ways....
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Quoting Orcasystems:


I ignored it.. my Halo was in danger :)


Member Since: August 22, 2008 Posts: 12 Comments: 6010
GFS will update by 0430Z for their 00UTC run
Model: GFS Created By: NCEP Daily Updates: 4 Update times: 03:30-04:45 | 09:30-10:45 | 15:30-16:45 | 21:30-22:45 (GMT)
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Quoting StSimonsIslandGAGuy:


Wow Drakoen agreed with me completely! That's cool!


hahaha, thanks for the answer simons :)
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1117. Grothar
Quoting atmoaggie:

Viking don't have horns. I was educated on that a day or so ago. Not sure whom it was that blessed us with that knowledge.
(And the Minnesota NFL team apparently has it wrong)


Gee, I wonder who could have given you that information. That Minnesota blog was funny. I really got a good laugh at that. But by the way, did you ever look up the Viking horn thing?
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Quoting atmoaggie:

Viking don't have horns. I was educated on that a day or so ago. Not sure whom it was that blessed us with that knowledge.
(And the Minnesota NFL team apparently has it wrong)


We warned you about this earlier... its all that thinking that gives you the headaches
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Quoting Orcasystems:


Go look at post 386 on my Blog.. it would appear the Carols need all the help they can get :)

P.S. remember its in the Jokes section


That was cute! It's too bad she is not very intelligent!!
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Quoting Grothar:


This is getting scary. I just KNEW you had one hidden somewhere and were going to post it.


Timing is everything. lol
Member Since: August 22, 2008 Posts: 12 Comments: 6010
Quoting xcool:


thanks x :) looks wonderful!
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Jeff co-founded the Weather Underground in 1995 while working on his Ph.D. He flew with the NOAA Hurricane Hunters from 1986-1990.

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