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 hurricanejunky:


Does it look to be affecting us down here in Ft. Myers?


The center is forecast to enter around the Tampa area so, points southward will get the brunt.
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Quoting alaina1085:

Yup! Its located off I-10 between Baton Rouge and Lafayette. I giggle everytime I pass it.


Not really another funny name, but gets mutilated by those not from the area.

Tchoutacabouffa River
Member Since: August 22, 2008 Posts: 12 Comments: 6010
FLOOD, Just a suggestion --
BADGER Sore Muscle Therapy Massage & Body Oil

It's much different than 'bout anything in the drugstore "sore muscle" line...and really feels like it's penetrating (oh dear, STOP laughing...never mind, laughter is good for you)!

NO menthol...try this, "warming ginger & cayenne extracts...Rosemary, cardamom, lemongrass, thyme and safe." Smells great; less filling ... and LST will like it too!

Also comes in balm, which is portable, but oil
is best!
Here -- Badger products site:
Link

And then, there's acupuncture...fight those bolts and spasms with teeny little pinpricks...you won't hardly feel 'em...but bet you'd start to feel way better!
Member Since: August 19, 2008 Posts: 32 Comments: 1918
Quoting Buhdog:
thanks tornadude


no problem. I'm hoping for snow too
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Quoting TheCaneWhisperer:


The system is pegged to cross the peninsula Sat / Sun.


Does it look to be affecting us down here in Ft. Myers?
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157. xcool
good .i am enjoying my only day off in a weeks.
Member Since: September 26, 2009 Posts: 2 Comments: 15684
A brief Christmas interlude from today's ramblings. From 25 years ago (big hair days). How many can you name?

Member Since: August 22, 2008 Posts: 12 Comments: 6010
thanks tornadude
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Quoting alaina1085:

Yup! Its located off I-10 between Baton Rouge and Lafayette. I giggle everytime I pass it.


haha thats understandable :P
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Quoting presslord:
Flood...we're well...sounds like you're rebounding...

Amy...just check out "her" Adam's Apple...


LOL!
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Flood- I have been down here for 15 years...I really would love to have that for me and the kids. 1. I can get drunk and let the grandparents be grandparents 2. I will be on vacation with nowhere to go anything planned for 12 days (a record as an adult) 3. I actually sort of miss the sight and feel of a snowstorm and the look of trees with snow piled on them. Tired of the tropical side for a minute.....

wow... i never thought i would yearn snow!


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Quoting tornadodude:


LOL that is funny

Yup! Its located off I-10 between Baton Rouge and Lafayette. I giggle everytime I pass it.
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Quoting Patrap:
Yep, Pat...I think there should be some regulatory controls on her mouth, but then I do believe in freedom of speech...the only problem is that there will always be those that believe anything...Ann Coulter...**double shudder**

U betcha,..



You guys are starting to scare me with all these crazy quotes and quips from some of the most idiotic people on the planet. Are you being assimilated?
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It seems like the conference in San Fran could've been done via webcast or something. I don't understand why if global warming is caused by man, why so many would want to jump on a plane to go to this meeting.
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And outside of any severe weather discussions. Have to see how things evolve through the week.
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145. xcool
btwntx08 hey ;) how your doin
Member Since: September 26, 2009 Posts: 2 Comments: 15684
Quoting hurricanejunky:


That's GREAT news although the local forecasts are only calling for 50% chance on Thur/Fri. No cold for Christmas either although a couple days in the 40's in the next week are expected. Yippee! (sarcasm inserted)


oh come on, you know you are excited about it :P jk
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Quoting hurricanejunky:


That's GREAT news although the local forecasts are only calling for 50% chance on Thur/Fri. No cold for Christmas either although a couple days in the 40's in the next week are expected. Yippee! (sarcasm inserted)


The system is pegged to cross the peninsula Sat / Sun.
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Quoting alaina1085:

There is one names Gross Tete! LOL. Its said gross tet, but some think its gross tee tee! LOL.


LOL that is funny
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Quoting Jeff9641:
I haven't heard anyone mention anything about the potential for severe weather for the Florida penisula on Friday. One would think with a low of 1000 to 1004 milibars going over a very warm humid airmass would be a great recipe for nasty weather across Florida. We will definitly get more beneficial rain across the penisula either way.


That's GREAT news although the local forecasts are only calling for 50% chance on Thur/Fri. No cold for Christmas either although a couple days in the 40's in the next week are expected. Yippee! (sarcasm inserted)
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Quoting AwakeInMaryland:
LOL. Is there REALLY a LA town named "Boot-ee"?
Pr. "Boot-(long)A"

There is one names Gross Tete! LOL. Its said gross tet, but some think its gross tee tee! LOL.
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Quoting Buhdog:
my 11 and 6 year old praying for ohio (dayton) snow....they still have never seen it as we head north for the holidays sunday! cmon jack frost!

help me wu bloggers! Hotter than molasses in my wifes freshly baked cookies in Ft myers today... 84!


Forecast for Dayton, Ohio:

Sunday: A chance of snow showers. Mostly cloudy, with a high near 26. Chance of precipitation is 30%.

Sunday Night: A chance of snow showers. Mostly cloudy, with a low around 17. Chance of precipitation is 30%.
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137. xcool
Member Since: September 26, 2009 Posts: 2 Comments: 15684
Quoting JFLORIDA:


Oh yea, she means the CO2 caps.


oh alright
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Quoting NavalArtichoke:
"as our climate responds to the huge shove human activities are giving it."
Dear Dr. Masters, fellow UofM alumnus:
Please note that the polar icecap of Mars has also recently disappeared. Does this mean that NASA will have to pay carbon taxes for future Martian probes?
May I suggest that you present a treatise on sunspot trends, instead?


You are aware that the Martian ice caps wax and wane in a relatively predictable pattern, yes?
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133. xcool
Member Since: September 26, 2009 Posts: 2 Comments: 15684
Quoting Floodman:
Well, folks, my darlin LST and I are going to go and sample some holiday tamales (man, do I love a good tamale)....BBL from home hopefully

Play nice, folks...Santa's watching!


have a good one Flood!
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Well, folks, my darlin LST and I are going to go and sample some holiday tamales (man, do I love a good tamale)....BBL from home hopefully

Play nice, folks...Santa's watching!
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Climate change hits Mars
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Quoting TheCaneWhisperer:


Always a tough one to call for the peninsula.



Thanks for the update
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Quoting AwakeInMaryland:
I NEED YUMMY, EASY GUMBO RECIPE(S) for somewhat-challenged cook (myself)! One that can be made in small or large quantities (like easily doubled or tripled) would be most appreciated.



Check your WUmail!
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125. xcool



12z for pat
Member Since: September 26, 2009 Posts: 2 Comments: 15684
"as our climate responds to the huge shove human activities are giving it."
Dear Dr. Masters, fellow UofM alumnus:
Please note that the polar icecap of Mars has also recently disappeared. Does this mean that NASA will have to pay carbon taxes for future Martian probes?
May I suggest that you present a treatise on sunspot trends, instead?
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Quoting StormW:
COASTAL AND OFFSHORE SYNOPSIS DECEMBER 15, 2009 ISSUED 2:10 P.M. EST


Always a tough one to call for the peninsula.
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I wonder if the good Doc will post an update to this entry or simply post these #'s in a separate entry tomorrow...
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Quoting presslord:
Flood...we're well...sounds like you're rebounding...

Amy...just check out "her" Adam's Apple...


Yessir, I'm pretty much kicking a$$ and taking names...most days...then there are those other ones, but we tend not to dwell on them
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JF,

University of Alabama - Huntsville (UAH) satellite derived temperatures also show November as the warmest on record @ 0.50C.

RSS has it at @ 0.33C - or 5th warmest.
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Quoting hurricanejunky:


I'm doing well, the holidays are always a nice time of year. Not cold yet but maybe a little cold spell before Christmas. It's REALLY cold in your neck of the woods, huh? I'm glad you're doing so well. Hopefully you'll stay pain free for many years to come.


Well, my titanium bolts are healing so I have this itching/hurting sort of thing going on about and inch to 2 inches below the skin that I can't do anything about, but other than that I'm good...I move better and with less pain all the time though I think if my PT guy at the hospital knew how much I'm walking these days he might be a little upset with me; I just want to get back to some semblence of normal as soon as possible
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Quoting AwakeInMaryland:
Who'll stop Awake aka AIM now that she's finally learned how to post an image? NOT THIS GUY, although his colleagues keep trying!



UGH! My taco bell lunch is creeping back up...
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"...as our climate responds to the huge shove human activities are giving it."

Dr. Masters:
Please note that the polar icecap of Mars has also disappeared recently. Consequently, I suppose that we should ban all probes to Mars, and tax NASA for this outrage. We humans are SO destructive!

Alternative line of thought: Mightn't sunspots have anything to do with these phenomena?
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Flood...we're well...sounds like you're rebounding...

Amy...just check out "her" Adam's Apple...
Member Since: Posts: Comments:

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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.