Future abrupt loss of Arctic sea ice

By: Dr. Jeff Masters , 5:53 PM GMT on February 22, 2007

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We've heard a lot about the melting sea ice in the Arctic. The steady loss of the polar ice cap may endanger the polar bear, but provide new shipping channels and opportunities for commercial exploitation of the Arctic. Since 1979 (the year satellite imagery of the north pole first became available), the areal coverage of the Arctic sea ice has shrunk by about 10% in winter (4% per decade) and 20% in summer (8% per decade). The loss of sea ice, when plotted on a graph (Figure 1), has roughly followed a straight line over time. There are a few noisy ups and downs, reflecting colder and warmer years than average. A trend that approximately follows a straight line is called a "linear" trend. A continued linear summertime 8% per decade loss of sea ice would leave the summertime Arctic Ocean ice-free by 2100. The ocean would still partially freeze in winter, with about 50% of the ocean covered with ice.



Figure 1. Average September Arctic sea ice coverage as observed by satellites between 1979 and 2006. Image credit: NOAA's National Snow and Ice Data Center.

However, there is a distinct possibility that Arctic sea ice loss may show a sudden non-linear decline in coming years. The loss of sea ice with time may no longer follow a nice straight line, but instead suddenly accelerate, allowing the Arctic sea ice to suffer a sudden and complete disintegration in just a decade. The result would be an ice-free Arctic Ocean for the first time since before the last ice age. This possibility was explored in a December 2006 paper (Holland et al.), titled "Future abrupt reductions in the summer Arctic sea ice". The authors ran the Community Climate System Model, one of the top climate models used to formulate the "official word" on climate, the 2007 Intergovernmental Panel on Climate Change (IPCC) report. The model was run for the years 1979-2006, and successfully predicted the 20% loss of summer sea ice during that period. The model then assumed that levels of greenhouse gases would continue to increase, until a doubling of CO2 levels occurred in 2100. This is considered a "middle-of-the-road" scenario, and assumes a reasonable sequence of events will unfold over the coming decades: humans will make some modest efforts to control greenhouse emissions, but not enough to prevent dangerous climate change. The model found that Arctic sea ice continued to decline linearly until about 2024, resulting in about 60% sea ice coverage in September (Figure 2). During this period, the vertical thickness of the sea ice declined from about four meters to one meter. Beginning in 2025, the rate of sea ice loss suddenly tripled, resulting in the total loss of the summertime polar sea ice by 2040. The authors theorize that once the ice reaches a critical thickness--in this case, one meter--the processes that create open water suddenly become more efficient, resulting in a rapid disintegration of the remaining ice.




Figure 2. September Arctic sea ice extent observed in 1979 (yellow line), and 2005 (white area). The predicted coverage of sea ice by Holland et al. (2006) is shown for 2015 (red line) and 2040 (green line). Their model predicts that sea ice in summer by 2040 will occur only in narrow bands along the Canadian Arctic coast. However, there will still be about 50% sea ice coverage in winter. Original image taken from NASA.

The authors tested 11 other models that were also used to formulate the 2007 IPCC report. Six of these 11 models also showed similar sudden losses of the summer sea ice. When these models were run assuming that dramatic efforts to cut greenhouse gas emissions will be made over the coming decades, only 3 of the 15 models tested showed sudden summer sea ice losses.

The authors concluded that "abrupt changes in the summer Arctic sea ice cover are quite likely and can occur early in the 21st century, with the earliest event in approximately 2015". Given that just over 50% of the models tested show such an effect, it is by no means a sure thing that we'll see a total loss of Arctic sea ice by the middle of the century. However, the results should be impetus to drastically cut greenhouse emissions soon, as the probability of an ice-free Arctic increases significantly if we do nothing.

This is the fourth in a series of five blogs on climate change in the Arctic that will appear every Monday and Thursday. Part five is: Why should we be concerned about an ice-free Arctic Ocean? This one might wait a few extra days, as there are other topics I may want to talk about. My next blog will be Monday.

Also, be sure to visit our new Climate Change blog, written by Dr. Ricky Rood of the University of Michigan.

References
Holland, M.M., C.M. Bitz, B. Tremblay, 2006 "Future abrupt reductions in the summer Arctic sea ice", Geophysical Research Letters, 33, L23503, December 2006.

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107. hurricane23
1:58 AM GMT on August 09, 2007
In my opinion this 16 day forcast from the GFS is useless and should really be discounted.Any model that far out in time is at a very low skill level and is likely to be wrong.Adrian
Member Since: May 14, 2006 Posts: 8 Comments: 13786
106. BahaHurican
8:39 PM GMT on February 26, 2007
I've been trying to see what will drive this alleged southward turn. It was drifting west earlier today . . .
Member Since: October 25, 2005 Posts: 19 Comments: 22081
105. Skyepony (Mod)
2:25 PM GMT on February 26, 2007

The purple is catastrophic damage
Member Since: August 10, 2005 Posts: 162 Comments: 37829
104. BahaHurican
2:09 PM GMT on February 26, 2007
Here is another movie of Gamede.
Member Since: October 25, 2005 Posts: 19 Comments: 22081
103. BahaHurican
1:56 PM GMT on February 26, 2007

Member Since: October 25, 2005 Posts: 19 Comments: 22081
102. BahaHurican
1:54 PM GMT on February 26, 2007
Looks like Gamede is going through an eyewall replacement cycle . . .
Member Since: October 25, 2005 Posts: 19 Comments: 22081
101. BahaHurican
1:50 AM GMT on February 26, 2007
Here's another view of Gamede, showing eye development and symmetry.
Member Since: October 25, 2005 Posts: 19 Comments: 22081
100. ridesthestorms
1:34 AM GMT on February 26, 2007
hello all had a nice day today
Member Since: July 19, 2006 Posts: 0 Comments: 47
99. BahaHurican
10:09 PM GMT on February 25, 2007
I was looking at the size and also the consolidation of the CDO. It is becoming more impressive with every view.
Member Since: October 25, 2005 Posts: 19 Comments: 22081
98. RobbieWM
9:50 PM GMT on February 25, 2007
It is huge and it blew up so quickly i couldn't believe it. The Indian ocean has been so active over the past couple of days
96. hurricane23
9:35 PM GMT on February 25, 2007
Organization continues with Gamede....


Member Since: May 14, 2006 Posts: 8 Comments: 13786
95. BahaHurican
7:46 PM GMT on February 25, 2007
I'm surprised this pic made it onto the blog . .

But I have been noting the strengthening trend also. Somewhere I saw it forecast to go to Cat 4 before landfall??

Looks like east coast Madegascar is already feeling some effects.
Member Since: October 25, 2005 Posts: 19 Comments: 22081
94. hurricane23
7:14 PM GMT on February 25, 2007
Gamede looks much better organized on visible imagery...

Free Image Hosting at www.ImageShack.us
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93. BahaHurican
4:32 PM GMT on February 25, 2007
Looks like it is practically stationary, and increasing in intensity.
Member Since: October 25, 2005 Posts: 19 Comments: 22081
92. BahaHurican
4:31 PM GMT on February 25, 2007
Gamede, last 24 hrs . .

http://www.meteo.fr/temps/domtom/La_Reunion/TGPR/saison/animation.htmlLink
Member Since: October 25, 2005 Posts: 19 Comments: 22081
91. BahaHurican
4:28 PM GMT on February 25, 2007
Another view:



Member Since: October 25, 2005 Posts: 19 Comments: 22081
90. BahaHurican
4:19 PM GMT on February 25, 2007
Latest satellite image of TC Gamede.



Member Since: October 25, 2005 Posts: 19 Comments: 22081
89. jake436
4:18 AM GMT on February 25, 2007
Patrap, I was checking in to see if I needed to warn you of the impending situation, but it's good to see you're on top of it. Be careful tonight, and stay safe.
Member Since: August 31, 2006 Posts: 0 Comments: 271
88. V26R
3:44 AM GMT on February 25, 2007
WOW Looks like a NASTY night down South
Link

I gotta check out the snowblower AGAIN,
Winter Storm Watch just issued for us up here!
Member Since: July 20, 2006 Posts: 0 Comments: 1762
87. Skyepony (Mod)
2:01 AM GMT on February 25, 2007
That storm looks ugly. They've had tennis ball size hail in Dermott, AK. SPC storm reports..

Tornado got a church in MS. Some storm spotters caught some 70mph winds on a handheld in LA.
Member Since: August 10, 2005 Posts: 162 Comments: 37829
86. Skyepony (Mod)
1:57 AM GMT on February 25, 2007
Favio news

A cyclone that hit Mozambique only days after disastrous floods, left at least 10 people dead and 70 injured in the east of the country, a Red Cross official said on Saturday.

Cyclone Favio flattened most of the worst-hit town, Vilankulo in coastal Inhambane province, 800km northeast of the capital Maputo on Thursday.


the rest of the article
Member Since: August 10, 2005 Posts: 162 Comments: 37829
84. Skyepony (Mod)
1:53 AM GMT on February 25, 2007
Humba
Member Since: August 10, 2005 Posts: 162 Comments: 37829
82. HadesGodWyvern (Mod)
8:52 PM GMT on February 24, 2007
cyclone tropical gamede
85 knots 10 min sustained winds with wind gusts up to 120 knots.

◘ Metro France has upgraded the orange alert to a red alert late this evening for Reunion.
- Red Alert means that danger is imminent
◘ Mauritius Meteorological Service has the Tropical Warning Class 3 still in effect.
Member Since: May 24, 2006 Posts: 50 Comments: 45283
81. Patrap
8:50 PM GMT on February 24, 2007
FOR JEFFERSON PARISH RESIDENTS IN SE LOUISIANA KENNER READY FOR POSSIBLE STORM THREAT
Posted by Wanda Miles February 23, 2007 20:52
Kenner Bulletin Index

Print | Email
Kenner, La. - Faced with possibility of another round of hazardous weather Saturday night and Sunday morning like that which hit the area the morning of February 13, Mayor Ed Muniz said Kenner is ready to warn its citizens and provide temporary shelter for residents who live in trailers or homes that cannot withstand high winds.

The National Weather Service (NWS) has said a weather front expected to move toward Southeast Louisiana from Texas over the weekend may generate hail and possible tornados like the weather system that struck Westwego and New Orleans 11 days ago.

Muniz said Jefferson Parish is expected to trigger warnings to local communities in the event the NWS places the parish under a tornado warning.

Plans call for parish fire dispatchers to alert all fire stations in the unincorporated areas of Jefferson as well as fire dispatch centers in Kenner and Gretna. Parish officials said that if severe weather warnings are posted during hours that citizens would normally be expected to be asleep, fire trucks would be called onto the driveways at their respective stations and sound their air horns and sirens for a period of at least three minutes in an effort to wake the community.

Kenner Fire Chief John Hellmers said his department would do the same to avoid any confusion between the adjacent fire districts, especially along the city's eastern border.

Muniz said a severe storm or tornado warning will also result in the opening of the Woodlake Gymnasium as a temporary shelter. The gym is at 121 W. Esplanade Avenue, at the intersection of Grandlake Boulevard. The shelter would stay open until the severe weather threat is over.

"That way, citizens who are unsure about whether they should stay in their current living quarters will have an alternative place to go if they so choose," he said.

"And I urge all Kenner residents to keep posted via TV, radio and other reliable means about the progress of any predicted severe weather, regardless of the hour, so they can make an informed decision about the safety of themselves and their families.
Member Since: July 3, 2005 Posts: 423 Comments: 128240
80. Patrap
8:43 PM GMT on February 24, 2007
To my SE Louisiana and Gulf Coastal fellow FEMA trailer..and Mobile Home residents.A powerful storm system is Forcasted to move thru the SE La..Coastal Miss region.There is a risk of Severe Activity along with damaging winds and Possible Tornadoes.PLease keep up on the Situation as it develops.At this time the threat timing looks to be between 4pm-10pm CST .However,the exact timing of the System is still uncertain.If one hasnt already,purchase a NOAA radio to compliment your Action Plan.Its Money well spent and could possibly be the only warning youll get in a rapidly Developing Serious Weather event as forecasted..Patrap
Member Since: July 3, 2005 Posts: 423 Comments: 128240
79. tornadodude
6:35 PM GMT on February 24, 2007
Great Bend Automatic Weather Observing / Reporting
Last Update on Feb 24, 12:15 pm CST


Overcast

54F
(12C) Humidity: 67 %
Wind Speed: S 3 MPH
Barometer: 29.16"
Dewpoint: 43F (6C)
Visibility: 10.00 mi.
More Local Wx: 3 Day History:



Member Since: June 28, 2006 Posts: 25 Comments: 8327
78. pottery
4:50 PM GMT on February 24, 2007
Good afternoon. Anyone on ?
Member Since: October 24, 2005 Posts: 0 Comments: 24307
76. hurricane23
1:58 PM GMT on February 24, 2007
Ryang check mail.Thanks
Member Since: May 14, 2006 Posts: 8 Comments: 13786
75. ryang
1:52 PM GMT on February 24, 2007
23 check your mail!
Member Since: August 25, 2006 Posts: 329 Comments: 12432
74. ryang
1:45 PM GMT on February 24, 2007
Morning all.
Member Since: August 25, 2006 Posts: 329 Comments: 12432
73. hurricane23
1:43 PM GMT on February 24, 2007
Hey stormw!

How are you doing its been a while.
Member Since: May 14, 2006 Posts: 8 Comments: 13786
71. hurricane23
1:37 PM GMT on February 24, 2007
Gamede looking well organized on this satelitte image from mtotec.


Member Since: May 14, 2006 Posts: 8 Comments: 13786
70. MarcKeys
12:58 PM GMT on February 24, 2007
How much will this melting effect the sea level? I have heard that sea levels would rise as much as 20 feet but you do not mention it here.

Florida Keys Fishing
69. Patrap
12:45 PM GMT on February 24, 2007
KENNER READY FOR POSSIBLE STORM THREAT
Posted by Wanda Miles February 23, 2007 20:52
Kenner Bulletin Index

Print | Email
Kenner, La. - Faced with possibility of another round of hazardous weather Saturday night and Sunday morning like that which hit the area the morning of February 13, Mayor Ed Muniz said Kenner is ready to warn its citizens and provide temporary shelter for residents who live in trailers or homes that cannot withstand high winds.

The National Weather Service (NWS) has said a weather front expected to move toward Southeast Louisiana from Texas over the weekend may generate hail and possible tornados like the weather system that struck Westwego and New Orleans 11 days ago.

Muniz said Jefferson Parish is expected to trigger warnings to local communities in the event the NWS places the parish under a tornado warning.

Plans call for parish fire dispatchers to alert all fire stations in the unincorporated areas of Jefferson as well as fire dispatch centers in Kenner and Gretna. Parish officials said that if severe weather warnings are posted during hours that citizens would normally be expected to be asleep, fire trucks would be called onto the driveways at their respective stations and sound their air horns and sirens for a period of at least three minutes in an effort to wake the community.

Kenner Fire Chief John Hellmers said his department would do the same to avoid any confusion between the adjacent fire districts, especially along the city's eastern border.

Muniz said a severe storm or tornado warning will also result in the opening of the Woodlake Gymnasium as a temporary shelter. The gym is at 121 W. Esplanade Avenue, at the intersection of Grandlake Boulevard. The shelter would stay open until the severe weather threat is over.

"That way, citizens who are unsure about whether they should stay in their current living quarters will have an alternative place to go if they so choose," he said.

"And I urge all Kenner residents to keep posted via TV, radio and other reliable means about the progress of any predicted severe weather, regardless of the hour, so they can make an informed decision about the safety of themselves and their families.
Member Since: July 3, 2005 Posts: 423 Comments: 128240
68. Skyepony (Mod)
5:33 AM GMT on February 24, 2007
at the bottom there it says the max is 30mm/hr so I nust have been mistaken with the 25.
Member Since: August 10, 2005 Posts: 162 Comments: 37829
67. Skyepony (Mod)
5:31 AM GMT on February 24, 2007
Got a good rainrate shot on Gamade

up to about 25mm/hr.
Member Since: August 10, 2005 Posts: 162 Comments: 37829
66. Skyepony (Mod)
5:26 AM GMT on February 24, 2007
Check out the Dust..
Member Since: August 10, 2005 Posts: 162 Comments: 37829
65. Skyepony (Mod)
4:56 AM GMT on February 24, 2007
UNICEF: Children Are the Hardest Hit by Cyclone Favio and Flooding in Mozambique
UNICEF Canada opens funding appeal

MAPUTO, MOZAMBIQUE and TORONTO, ONTARIO--(CCNMatthews - Feb. 23, 2007) - Children are bearing the brunt of tropical Cyclone Favio, said UNICEF today as staff on the ground in Mozambique began their emergency response to the second disaster to hit the country in less than a month.

"This cyclone strikes a severe blow to an area that has already been devastated by flooding over the past few weeks," said Leila Pakkala, head of UNICEF's Country Office in Mozambique. "Children account for half of the affected populations."

A UNICEF assessment team landed today in Vilankulos, the first town to be hit by Cyclone Favio, to conduct a rapid needs assessment with government and other partners. Strong winds - reaching over 200 km/hour - seriously damaged homes and crucial public facilities, including blowing roofs off of schools and the maternity ward of the town's main hospital.
Member Since: August 10, 2005 Posts: 162 Comments: 37829
64. Ldog74
4:45 AM GMT on February 24, 2007
Gamede is looking pretty good on satellite. If it stalls or slows down over those mountains however, this could have much more negative effects than your "average" cat3+ hurricane. Also, notice the bay/inlet/thingamabob on the NE part of the island. Reminds me of Tampa Bay.
Member Since: June 11, 2006 Posts: 0 Comments: 165
63. HadesGodWyvern (Mod)
4:45 AM GMT on February 24, 2007
10 min sustained winds

0300am UTC
Metro France: RSMC Reunion

Cyclone Tropical Gamede
75 knots sustained winds with wind gusts up to 105 knots

◘ Metro France has issued the ORANGE ALARM for Reunion which means danger is possible in 24 hours.
◘ Mauritius Meteorological Service has issued Tropical Cyclone Warning Class 3 for Mauritius.
Member Since: May 24, 2006 Posts: 50 Comments: 45283
62. Hardcoreweather
4:36 AM GMT on February 24, 2007
It's nice to see some tropical action this time of year to get out of the winter time blues :)

This tropical system looks rather wicked... it will be interesting to see the reports that come out of there after landfall....

Hardcoreweather.com Forums
61. LowerCal
3:25 AM GMT on February 24, 2007
Shaded relief map of Madagascar - click map to make larger.
Member Since: July 26, 2006 Posts: 58 Comments: 9168
60. Patrap
2:51 AM GMT on February 24, 2007
CIMSS MIMIC GAMEDE Vmax 105Knts here. Link
Member Since: July 3, 2005 Posts: 423 Comments: 128240
59. hurricane23
2:37 AM GMT on February 24, 2007
Madagascar needs to complete all preparations as there is a major hurricane right in there door step moving in there gerenal direction.




Member Since: May 14, 2006 Posts: 8 Comments: 13786
58. Patrap
2:24 AM GMT on February 24, 2007
To my SE Louisiana and Gulf Coastal fellow FEMA trailer..and Mobile Home residents.Tommorw,Sat the 24th..a powerful storm system is Forecasted to move thru the SE La..Coastal Miss region.There is a risk of Severe Activity along with damaging winds and Possible Tornadoes.PLease keep up on the Situation as it develops tommorrow.At this time the threat timing looks to be between 6pm-12midnight CST Saturday.However,the exact timing of the System is still uncertain.If one hasnt already,purchase a NOAA radio to compliment your Action Plan.Its Money well spent and could possibly be the only warning youll get in a rapidly Developing Serious Weather event as forecasted..
Member Since: July 3, 2005 Posts: 423 Comments: 128240

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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.