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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Excellent post Doc. Thanks.

Last one too.
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Climate variability N TX STYLE :0)

Member Since: August 25, 2009 Posts: 20 Comments: 6785
Pretty obvious where the flooded areas are.

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510. amd
Quoting Bordonaro:
Good evening folks! WOW!! TC Lauruence is not messing aroing. I hope the great folks in Australia heed the warnings and stay safe!!

Talks about "climate variability", the things that make follow the weather, exhilarating.

1) 20 inches of rain in the NOLA area
2) 50F in Moscow, Russia
3) -51C in Alberta, Canada
4) TC Lauruence a CAT 4 Cyclone, and the season just started. And a TC convention in the SW PAC, near Australia.
5) Snow in Dallas, Houston, Corpus Christi, the NOLA area, Jackson into AL, before it snowed in Chicago, South Bend, NYC, Boston.

I just can't wait to see what the last 10-14 days have in store for the US, and the whole world!!


I think it is likely that due to the El Nino induced sub tropical jet, a low coming out of the gulf, and a piece of the polar vortex diving down from Canada, a big storm will form in the Western Atlantic on sunday and monday.

The only question is this: Does the storm form close enough to the coast and give heavy snow from Raleigh to Boston, or does the storm bomb out well to the se of cape cod, and lash the Canadian Maritimes with substantial wind and snow, while leaving most of the eastern US cold and dry

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Charlotte, NC this weeks GFS forecasts! WOW!!!

Member Since: August 25, 2009 Posts: 20 Comments: 6785
looks like I have a pretty good cold-front coming through around new years eve
Member Since: June 28, 2006 Posts: 24 Comments: 8185
Jesus...

398. stormobserver 1:57 AM GMT on December 16, 2009
Spathy is just a racist crank who got banned for 96 hours for posting racist pictures last summer


399. spathy 2:01 AM GMT on December 16, 2009
#398
Ok


OK??? OK???

NO, NOT OKAY!!!!


Sometimes leaders have to listen, and sometimes leaders have to lead, and sometimes we need to get new leaders.

Otherwise, most of the U.S. population wouldn't even be able to vote out the leaders who don't listen, can no longer lead, don't wish to, or who have lost their way.


Member Since: August 19, 2008 Posts: 32 Comments: 1918
Member Since: June 28, 2006 Posts: 24 Comments: 8185
Quoting Grothar:



Dude, Flood couldn't have been more than 10 years old. What is wrong with you. He's our Bud!
He was probably up there firing one up when it blew....While enjoying the view.:)
Member Since: September 27, 2007 Posts: 1 Comments: 19604
Quoting GeoffreyWPB:
I know what you meant Matt...A lot of one-line jokes, that I think he would like!


oh ok haha yeah, I'm chock full of 'em

Quoting Grothar:



Dude, Flood couldn't have been more than 10 years old. What is wrong with you. He's our Bud!


LOL totally kidding :P
Member Since: June 28, 2006 Posts: 24 Comments: 8185
Folks, any word on the ECMFW and GFS forecast for ice/snow for the SE, Mid Atlantic and the NE US, for this week??
Member Since: August 25, 2009 Posts: 20 Comments: 6785
Quoting tornadodude:


Floodman was probably there :p



Dude, Flood couldn't have been more than 10 years old. What is wrong with you. He's our Bud!
Member Since: July 17, 2009 Posts: 64 Comments: 23744
Good evening folks! WOW!! TC Lauruence is not messing aroing. I hope the great folks in Australia heed the warnings and stay safe!!

Talks about "climate variability", the things that make follow the weather, exhilarating.

1) 20 + inches of rain in the NOLA area
2) 50F in Moscow, Russia
3) -51C in Alberta, Canada
4) TC Lauruence a CAT 4 Cyclone, and the season just started. And a TC convention in the SW PAC, near Australia.
5) Snow in Dallas, Houston, Corpus Christi, the NOLA area, Jackson into AL, before it snowed in Chicago, South Bend, NYC, Boston.

I just can't wait to see what the last 10-14 days have in store for the US, and the whole world!!
Member Since: August 25, 2009 Posts: 20 Comments: 6785
I know what you meant Matt...A lot of one-line jokes, that I think he would like!
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NWS in Raleigh warning people for possible strong winter storm already.




Long term /Friday night through Tuesday/...
as of 245 PM Tuesday...


Southeast coastal storm is possible early in the weekend...


For Friday night through sunday: as previous shifts have noted... a
continuation of a positive pna and negative nao pattern is expected
into the medium range... favoring generally cool and stormy weather
for the southeast. Unfortunately the latest round of operational
models does not buoy confidence in the details of this storm system.
They agree on the surface low exiting the northeast Florida coast to just
off the southeast coast Friday night... but then their solutions
diverge markedly. The GFS... which has not done too well lately
handling middle level potential vorticity maxima produced by Gulf Coast
convection... is among the wettest of the operational models over
western North Carolina Friday night and Saturday and this 12z run
is much wetter than its 06z run. The 12z Canadian has a more
positively tilted middle level trough compared to its more upright
00z run and as a result it shoots the surface low away from the
coast instead of deepening it along the middle Atlantic coast as its
00z run showed. And the European model (ecmwf)... whose 00z run bombed out the
surface low along the North Carolina coast Saturday night and Sunday
and threw precipitation west over the entire County Warning Area... is now even
deeper but faster with the surface low... and eerily resembles the
12z GFS tracking a strong low up the North Carolina coast. The 12z
gefs mean... however... supports the surface low moving away from
the Carolina coast by midday Saturday. With rather poor run-to-run
consistency and limited agreement among the models... do not want
to jump too quickly into a major coastal storm... but these latest
model trends do necessitate bringing in at least good chance probability of precipitation
in the southeast half of the County Warning Area with slight chances in the
northwest... mainly late Friday night through Saturday evening.
Further complicating the forecast are the partial thicknesses from
the 00z/12z European model (ecmwf) and 12z GFS which suggest a possible wintry mix
dominated by--or transitioning to--a band of wet snow on the
western and northern sides of the precipitation shield. As this is
day 4 of the forecast and confidence in the details is below
normal... will keep the forecast all liquid for now... as there is
plenty of time for the model solutions to converge. But... given
the recent operational model trends... the prevailing circulation
pattern... and the very cold nature of the air mass... there is a
risk of significant wintry precipitation over North Carolina with
this system... and people should certainly check back with later
forecasts in the ensuing days.
Expect lows of 32 to 37 Friday
night and Saturday night. Highs Saturday 38 to 45... and even
this may not be cool enough if there is greater precipitation
coverage. Will indicate a slow clearing Saturday night as the
middle level trough axis shifts overhead and to our east with
northwest surface flow through Sunday. Highs Sunday 40 to 47 with
GFS/European model (ecmwf) thicknesses well below seasonal normals.
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Quoting GeoffreyWPB:


So many one-liners....Flood is a good man.


I know he is, it wasnt an attack or anything. He is just old enough ;)
Member Since: June 28, 2006 Posts: 24 Comments: 8185
Quoting tornadodude:


Floodman was probably there :p


So many one-liners....Flood is a good man.
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492. Skyepony (Mod)
Quoting AstroHurricane001:


Rapid intensification has occured with many storms worldwide in the past few weeks.


Just odd to see it do that while repeatably making landfall. It's rare enough to see them bomb at landfall.
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Quoting Grothar:


Wise Guy! The weather played an important part of that disaster, and NO, I wasn't there in person.

Glad to see you finally spelled Hindenburg correctly.


Guess I am not fluent in spelling Nazi names.
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Quoting Grothar:


Wise Guy! The weather played an important part of that disaster, and NO, I wasn't there in person.

Glad to see you finally spelled Hindenburg correctly.


Floodman was probably there :p
Member Since: June 28, 2006 Posts: 24 Comments: 8185
Quoting GeoffreyWPB:
A tribute to Herbert Morrison



Wise Guy! The weather played an important part of that disaster, and NO, I wasn't there in person.

Glad to see you finally spelled Hindenburg correctly.
Member Since: July 17, 2009 Posts: 64 Comments: 23744
A tribute to Herbert Morrison

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Quoting Skyepony:
Laurence..dang intensified outrageous in the last 12 hrs while making landfall 3 times.. insane MIMIC



Rapid intensification has occured with many storms worldwide in the past few weeks.
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486. amd
Quoting Jeff9641:
In Orlando the local forecasters seem to think that this low in the gulf will be quite strong and move south of Tampa. The models I see show north of Tampa is this because the Low is forming further south?


not quite sure where your mets are getting their info. Looks to me that the GFS, and most other models that I have seen, have the low heading toward the big bend.

18Z GFS Gulf Low
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Quoting AussieStorm:

The area up where Laurence is, is full of tiny islands and only a few little towns that r well built and have evac centers
That is very cool. Prayers to them anyway. :)
Member Since: September 27, 2007 Posts: 1 Comments: 19604
Category 5 cyclone menaces Kimberley coast
Wednesday December 16, 2009 - 14:02 EDT

A Kimberley pearling community off the WA coast is bracing for the onslaught of Tropical Cyclone Laurence which has been upgraded to a category 5 storm.

The small but intense cyclone has increased in strength packing winds of 285 kilometres per hour at its centre.

It is estimated to be about 35 kilometres from the pearling community of Kuri Bay.

The Bureau of Meterology is predicting very destructive winds and is advising residents to seek shelter.

The Fire and Emergency Services Authority's District Manager Gordon Tiddums says the agency is on standby to go to Kuri Bay.

"They're batting down and they're looking after themselves," he said.

"Once the all clear is given, we'll contact Kuri Bay and if necessary we'll go in and see what damage has been done."

There have been no reports of major damage.

A yellow alert is current for people in or near the communities of Mitchell Plateau, Koolan Island and Cockatoo Island.

The communities of Cape Leveque, One Arm Point, Djarindjin, Lombadina and Derby are on blue alert.

- ABC


I'm out.... gotta go to work. will be back later tonight. Stay safe all.
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Quoting Jeff9641:


It probably all falling over the swamps right now which is great because Oct. and Nov. where very dry and hot here in Florida.
No doubt, the rain is needed. They should have a wet winter season if the usual El-Nino pattern holds. No tornadoes I hope.
Member Since: September 27, 2007 Posts: 1 Comments: 19604
Quoting GeoffreyWPB:


No watches or warnings out for us now.


Hey Geoffrey you are getting what we just had here in Mobile..... Over the last 4 days we here along the north gulf coast have had as much as 12 to 14 inches of rain........ It is finally over for us here......

taco :0)
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Quoting Chicklit:

Hi Aussie, what are you near on the map of Australia? Between Sydney and Melbourne?

I am in a suburb of Sydney
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Quoting hydrus:
I fear Lawrence has already finished off about a years worth of damage. Hopefully it will weaken rapidly.

The area up where Laurence is, is full of tiny islands and only a few little towns that r well built and have evac centers
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Quoting Chicklit:
Calusakat, since your fish cannot speak for themselves then they are stuck with your opinion.
The point of Ricky Rood's blog and my post is, to apply reason to irrationality is an exercise in futility.

They don't have to.

The mortality rate is essentially non-existent. Except for the occasional conflict or old age that is. The reason is that our systems have been designed to clean the water properly. It is indeed crystal clear and we are careful to isolate new fish in a separate tank which contains water from the main tanks and watch them for a short while to make sure they are acclimated to the new system etc.

So demanding truth and unaltered data is irrational?

Wow, a new definition must have cropped up lately that puts a new spin on the work 'irrational'.

irrational...to insist on truth and honesty.

Do you have a copy of that comedic version of the dictionary, I would love to read it.

And as you said...Love, peace, joy are the hallmarks of this season! No matter what...

Back at ya.


Member Since: October 10, 2008 Posts: 0 Comments: 716
Quoting Jeff9641:


I live in Orlando but I'm noticing incredible rainfall rates as these storms are slow moving. Western Palm Beach county has had 5 to 6" so far and it is still raining.
My old stomping grounds. They are up to snuff when it comes to the heavy stuff. It probably be o.k.
Member Since: September 27, 2007 Posts: 1 Comments: 19604
Quoting AussieStorm:


Yeah....started December 1... very early start to the season

Hi Aussie, what are you near on the map of Australia? Between Sydney and Melbourne?
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Quoting hydrus:
A foot or two? If you do not have a boat, now is a good time to buy one.lol


No watches or warnings out for us now.
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Just to give everyone a heads up... I wont be online from next Monday night. I am taking a week off and going to visit my parents about 450km's away, at a little country town called Cooma. While i am there, I hope to walk to the highest point of Australia, i will be taking many pics while i am away, If you want to join me on facebook, send me a Wu-mail and I'll add u to my friends list.
Cheers AussieStorm
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Quoting AussieStorm:


Yeah....started December 1... very early start to the season
I fear Lawrence has already finished off about a years worth of damage. Hopefully it will weaken rapidly.
Member Since: September 27, 2007 Posts: 1 Comments: 19604
I'm starting to think that this is a Where The Front Stalls question and we've got two views: 1)our NWS which now has it stopping n/o Miami, which, being Our Guys, always wins my vote; and 2) a datafeeed which shows up in my local WU weather pages (source unknown; where do the forecasts come from?)which apparently sees a more intense and more southerly Gulf low.
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Quoting hydrus:
This is just the beginning of your tropical cyclone season right? And already a cat-5 hitting?


Yeah....started December 1... very early start to the season
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Quoting Jeff9641:
West Palm Beach is about to get hammered as storms are building all around the city. Looks like someone is going to see a foot or two of rain in that area tonight. Heed all flood percautions in Palm Beach county as flash flooding will occur in that area.
A foot or two? If you do not have a boat, now is a good time to buy one.lol
Member Since: September 27, 2007 Posts: 1 Comments: 19604
Calusakat, since your fish cannot speak for themselves they are stuck with your opinion.
The point of Ricky Rood's blog and my post is, to apply reason to irrationality is an exercise in futility.
Goodnight.
Love, peace, joy are the hallmarks of this season! No matter what...
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Quoting Drakoen:
WPB, the weekend looks cold for Lake Worth with temperatures in the lower 40s on Sunday and Monday.


Thanks Drak. Finally, it's going to feel like the holidays.
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Quoting AussieStorm:


I am watching Him very closely
This is just the beginning of your tropical cyclone season right? And already a cat-5 hitting?
Member Since: September 27, 2007 Posts: 1 Comments: 19604
Quoting GeoffreyWPB:
453. calusakat
Your spelling has never been worse. Are you okay tonight?

Whut?

Just cuz I slipped into a little Justin Wilson for a sec?

Heh Heh.


Member Since: October 10, 2008 Posts: 0 Comments: 716

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About

Jeff co-founded the Weather Underground in 1995 while working on his Ph.D. He flew with the NOAA Hurricane Hunters from 1986-1990.