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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Quoting xcool:


thanks x :) looks wonderful!
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lol great minds think alike orca,pcola? =P
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Quoting Grothar:


Them there better be Viking horns you be talking about!!!!! LOL

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)
Member Since: August 16, 2007 Posts: 6 Comments: 12463
Quoting Grothar:


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


I ignored it.. my Halo was in danger :)
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1109. Grothar
Quoting Orcasystems:


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


Them there better be Viking horns you be talking about!!!!! LOL
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Quoting Bordonaro:


Try this link for weather updates for NC. Allan Hoffman is a meteorologist, out of Raliegh, NC, he has 10 yrs local experience and focuses on weather events in NC and around the US, below is the link! Be Blessed my friend!!

Link


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
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There just isn't any valid reason to come into Dr M's blog and bash him...bash the data behind the message, bash the conclusions (preferably with a good discussion of the reasons you do so), but to bash the messenger, that really does believe in what he says, right or wrong, is not acceptable.

Most visitors here probably do not visit because they think him a joke.
Member Since: August 16, 2007 Posts: 6 Comments: 12463
1106. Grothar
Quoting PcolaDan:




This is getting scary. I just KNEW you had one hidden somewhere and were going to post it.
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Quoting pinehurstnc:
no offense to any one,, i came here in 2005,, just to chat and learn about all WEATHER,, i have a basic back ground in met,, one thing , i know , i am only human,, therefore,, i cannot control it,, weather will come,, and yet , it shall pass,, , ,so get along, its only something ,we have not yet, mastered


Try this link for weather updates for NC. Allan Hoffman is a meteorologist, out of Raliegh, NC, he has 10 yrs local experience and focuses on weather events in NC and around the US, below is the link! Be Blessed my friend!!

Link
Member Since: August 25, 2009 Posts: 20 Comments: 6785
Quoting PcolaDan:
And tell me, which one is really AIM? :)



LOL
Member Since: June 28, 2006 Posts: 25 Comments: 8360
Quoting CatastrophicDL:


You always say things just the right way! It's been a while, but I wanted to ask a favor in advance. I decided to sign up for Met classes this coming semester and may need some help understanding a few things from time to time from all my super knowledgable friends on WU. Might you be available to help at all?

Of course! (you felt the need to ask?)

One of my favorite subjects...
;-)
Member Since: August 16, 2007 Posts: 6 Comments: 12463
And tell me, which one is really AIM? :)

Member Since: August 22, 2008 Posts: 12 Comments: 6010
Quoting Grothar:


That's Ok Orca, I trip over mine at least twice a day. It's annoying isn't it?


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


That's Ok Orca, I trip over mine at least twice a day. It's annoying isn't it?


Member Since: August 22, 2008 Posts: 12 Comments: 6010
Quoting Drakoen:


You could just leave it unmodified...


I put it in as unmodified. You can also right click on the image, right click properties, copy the URL, post that in your browser, and the full image will come up! I do it all the time to make the images their original size..
Member Since: August 25, 2009 Posts: 20 Comments: 6785
Quoting Orcasystems:


They ran him off again.. all 3 of him
.

Member Since: August 22, 2008 Posts: 12 Comments: 6010
1096. Grothar
Quoting Orcasystems:


I am impressed, I have not even had to shine it this year.... I have been the poster boy for S&I.


That's Ok Orca, I trip over mine at least twice a day. It's annoying isn't it?
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Quoting Orcasystems:


They ran him off again.. all 3 of him

ROFL! You know while I understand and feel it is only logical that humans somehow impact the weather patterns of the earth, all this arguing makes me think of the evolution/creation argument. I'm thinking that when scientists can make primordial sludge evolve into a human then I'll be on board. In every case, I don't feel science has proved it's point.
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1094. Drakoen
Quoting Bordonaro:


It was put in as 1280 x 1024 when I put it in! I'll try 1400 x 1200, I do not think it will look right.


You could just leave it unmodified...
Member Since: October 28, 2006 Posts: 57 Comments: 30575
Quoting Drakoen:
Bordonaro, could you change the dimensions of you image in the length so it's not so narrow....


It was put in as 1280 x 1024 when I put it in! I'll try 1400 x 1200, I do not think it will look right.
Member Since: August 25, 2009 Posts: 20 Comments: 6785
Quoting pinehurstnc:
no offense to any one,, i came here in 2005,, just to chat and learn about all WEATHER,, i have a basic back ground in met,, one thing , i know , i am only human,, therefore,, i cannot control it,, weather will come,, and yet , it shall pass,, , ,so get along, its only something ,we have not yet, mastered


FIVE POINTS for that comment!!
Member Since: August 25, 2009 Posts: 20 Comments: 6785
Quoting CatastrophicDL:

Where'd he go? The drama during hurricane season is something that always drives me to carbs!


They ran him off again.. all 3 of him
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anyone else sick of the GW debate and how its standing in the way of science. Seriously, this has set discoveries back another twenty years. I wish the good old doc would lay off and put some real weather info up. Like it or not...its not up to us right now, and its time to get back to science (not lobbying)
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1089. chawk
The Copenhagen event is showing the whole world a poor committment to addressing climate change. If the organizers and attendees were dedicated to the cause there would not be thousands of limos and private jets ferrying people including hollywood to and from the event. It would be held online. Al would not have to exagerate a respected scientist data to dramatize the effects of AGW to the point that all polar ice will be gone in 5-7years. The AGW beleivers would be much more effective if they would set a better example and get out of politics. Your only as good as the company you keep.
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Quoting Orcasystems:


True, I do miss seeing people loose it, and now that its so quite.. I miss JFV

Where'd he go? The drama during hurricane season is something that always drives me to carbs!
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1087. Drakoen
Bordonaro, could you change the dimensions of you image in the length so it's not so narrow....
Member Since: October 28, 2006 Posts: 57 Comments: 30575
no offense to any one,, i came here in 2005,, just to chat and learn about all WEATHER,, i have a basic back ground in met,, one thing , i know , i am only human,, therefore,, i cannot control it,, weather will come,, and yet , it shall pass,, , ,so get along, its only something ,we have not yet, mastered
Member Since: Posts: Comments:
Quoting CatastrophicDL:

There hasn't been much happening to stress people out this year. I haven't been on much since I decided to go back to school. I've missed you guys! I actually got my homework done before 10:30 tonight so I thought I'd say hi!


True, I do miss seeing people loose it, and now that its so quite.. I miss JFV

Not to mention... with all this GW chat... I have a massive Iggy list.. a new record
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00Z NAM 12-20-09 @72HRS, 850 MB Temps and 6 HR precip model. Notice a secondary L developing near GA/SC line?

Member Since: August 25, 2009 Posts: 20 Comments: 6785
Quoting Orcasystems:


I am impressed, I have not even had to shine it this year.... I have been the poster boy for S&I.

There hasn't been much happening to stress people out this year. I haven't been on much since I decided to go back to school. I've missed you guys! I actually got my homework done before 10:30 tonight so I thought I'd say hi!
Member Since: Posts: Comments:
Quoting CatastrophicDL:

Orca, OMGosh your halo is so shiny!


I am impressed, I have not even had to shine it this year.... I have been the poster boy for S&I.
Member Since: Posts: Comments:
1080. Drakoen
Quoting CatastrophicDL:

Hey Drak, it's been a while! I signed up for Met classes this semester. If there is something I don't understand can I maybe shoot you an email for some help?


Sure thing!
Member Since: October 28, 2006 Posts: 57 Comments: 30575
Looks like Laurence came in as a Cat 3.
Good news. I guess!
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Quoting Drakoen:


Yes...

Hey Drak, it's been a while! I signed up for Met classes this semester. If there is something I don't understand can I maybe shoot you an email for some help?
Member Since: Posts: Comments:
Quoting Orcasystems:
Are we still seeing/hoping/praying/voodoo worship/bribing the GW guys and/or guesstimating snow for Florida and the pan handle :)

Orca, OMGosh your halo is so shiny!
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1076. Drakoen
Quoting CatastrophicDL:
Atmo and Drak are you guys still online?


Yes...
Member Since: October 28, 2006 Posts: 57 Comments: 30575
Quoting atmoaggie:
1062: Detailing why you think what you do would have been a far better post. You just ruined any positive perceptions anyone, including fence-sitters, may have had about those of us that question the science and conclusions of AGW proponents.

Check your shoes.

You have made yourself look like an ideological fool, nothing more, and I know you know better.


You always say things just the right way! It's been a while, but I wanted to ask a favor in advance. I decided to sign up for Met classes this coming semester and may need some help understanding a few things from time to time from all my super knowledgable friends on WU. Might you be available to help at all?
Member Since: Posts: Comments:
Are we still seeing/hoping/praying/voodoo worship/bribing the GW guys and/or guesstimating snow for Florida and the pan handle :)
Member Since: Posts: Comments:
Christmas Light display from Lynn Creek Park at Joe Pool Lake, TX. Taken last night with our "pleasant Family outing"!


Any new model runs out showing S Plains/SE US snow for next week?? How's the E Coast Snowstorm shaping up?

Member Since: August 25, 2009 Posts: 20 Comments: 6785
Atmo and Drak are you guys still online?
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I try to stay away from the whole GW debate and have stayed off this blog for almost two years.

you know....screw that!

You have to be pretty arrogant to think you can prove what is going on. That is all.
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Quoting Grothar:


Hey atmoaggie, see that stream of real warm water right by the SE tip of Florida, well that's where I live. :P Always great weather.


Hawk, come back on now.
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1069. Grothar
Quoting atmoaggie:
1062: Detailing why you think what you do would have been a far better post. You just ruined any positive perceptions anyone, including fence-sitters, may have had about those of us that question the science and conclusions of AGW proponents.

Check your shoes.

You have made yourself look like an ideological fool, nothing more, and I know you know better.


Now you know why I respect you as do other!
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1068. Drakoen
The NAM 00z shows phasing earlier allowing the system to come up closer to the coast with a negatively titled 500mb trough axis. The deformation axis extends outwards toward Kentucky with a more moist solution.
Member Since: October 28, 2006 Posts: 57 Comments: 30575
according to that last snowfall map...ill wake up sunday to 12-16 inches of snow just 20 miles to the southeast of richmond...while i love a good snowstorm or 2 every year...ill see that when pigs fly...im betting on a dusting up to 4 inches...and thats pushing it...
Member Since: Posts: Comments:
1062: Detailing why you think what you do would have been a far better post. You just ruined any positive perceptions anyone, including fence-sitters, may have had about those of us that question the science and conclusions of AGW proponents.

Check your shoes.

You have made yourself look like an ideological fool, nothing more, and I know you know better.
Member Since: August 16, 2007 Posts: 6 Comments: 12463
1065. Grothar
Quoting atmoaggie:


I find the Wunderground SST map and the RTG (in your link) to be overly smoothed and have a lot of latency (age of measurement).

Otherwise, neat link!

I like the higher resolution SST sources, like this one: http://weather.msfc.nasa.gov/sport/modis/sst_comparison.html


(reduced, click for full size)

This is one of my favorites, anyway...(very few have global coverage in a single plot)


Hey atmoaggie, see that stream of real warm water right by the SE tip of Florida, well that's where I live. :P Always great weather.
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Quoting AstroHurricane001:


It's all on the Weather Underground SST map, and a larger version is accessible through Flash Tracker for tropical cyclones. Also, here's another site for current SSTs and anomalies, that I included in a post on a previous blog entry: Link


I find the Wunderground SST map and the RTG (in your link) to be overly smoothed and have a lot of latency (age of measurement).

Otherwise, neat link!

I like the higher resolution SST sources, like this one: http://weather.msfc.nasa.gov/sport/modis/sst_comparison.html


(reduced, click for full size)


This is one of my favorites, anyway...(very few have global coverage in a single plot)
Member Since: August 16, 2007 Posts: 6 Comments: 12463
1063. Drakoen
Nice snow north of the Tennessee River Valley and south of the Mason-Dixon Line.
Member Since: October 28, 2006 Posts: 57 Comments: 30575

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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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