Fabled Northwest Passage begins to re-freeze

By: Dr. Jeff Masters , 2:29 PM GMT on October 12, 2007

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This summer's dramatic loss of Arctic sea ice peaked on September 15, and the polar ice cap is finally beginning to re-freeze, according to a press release issued by the National Snow and Ice Data Center on October 1. Extent of the September polar sea ice fell 39%, compared to the 1979-2000 average. To put this loss in perspective, in one year we lost as much ice as we lost during the previous 28 years. Summertime Arctic sea ice is now at 50% of what it was in the 1950s (Figure 1). One may look at at graph and wonder, but what about sea ice loss in other seasons? It hasn't been nearly so severe. True, but it is the summer ice we care most about, since summer is when the thick, multi-year ice melts, which can then precondition the Arctic for much greater ice loss in future years. As sea ice melts in response to rising temperatures, more of the dark ocean is exposed, allowing it to absorb more of the sun's energy. This further increases air temperatures, ocean temperatures, and ice melt in a process know as the "ice-albedo feedback" (albedo means how much sunlight a surface reflects). There is an excellent chance that the summer of 2007 will be remembered as the "tipping point" for Arctic sea ice, when an irreversible ice-albedo feedback process firmly established itself.



Figure 1. Arctic sea ice extent since 1900, as estimated from satellite and ship reports compiled by Walsh and Chapman (2001). Image credit: University of Illinois cryosphere group.

Northwest Passage opens for the first time in recorded history
Long before the Panama and Suez Canals made commercial trading between the Atlantic and Pacific Oceans economically feasible, ships made the long and perilous trip around the African and South America continents. Explorers, traders, and world leaders looking for faster and less dangerous shipping routes to far-away areas of the world have long eyed two routes through the ice-choked Arctic Ocean--the fabled Northwest Passage, through the cold Arctic waters north of Canada, and the Northeast Passage, extending along the northern coast of Russia. The first recorded attempt to find and sail the Northwest Passage was in 1497, and ended in failure. The thick ice choking the waterways thwarted all attempts at passage for the next four centuries. Finally, in 1905, Roald Amundsen completed the first successful navigation of the Northwest Passage. It took his ship two-and-a-half years to navigate through narrow passages of open water, and his ship spent two cold, dark winters locked in the ice during the feat. More recently, icebreakers and ice-strengthened ships have on occasion battered their way through the ice-blocked route.



Figure 2. The Northwest Passage shipping route (red line) and Northeast Passage (green line) superimposed on an ice coverage map from August 22, 2007. The Northwest Passage was ice-free and navigable for 36 days between August 14 and September 18, 2007. The Northeast Passage was blocked by a narrow strip of ice most of the summer. Image credit: National Snow and Ice Data Center.

Times are changing. In 2001, the Bering Strait, a key portion of both the Northwest and Northeast Passages, was completely ice free. This was followed in 2005 by record-breaking sea-ice melt in the Arctic, leading to the first ever recorded opening of the Northeast Passage. The fabled Northwest Passage remained closed in 2005. Arctic ice recovered a bit in 2006, and both passages remained closed. But the unprecedented melting during the summer of 2007 saw the Northwest Passage become ice-free and navigable along its entire length without the need for an icebreaker as of August 14, 2007. Remarkably, the Northwest Passage remained ice-free for 36 days, finally refreezing over a small section on September 19. The Northeast Passage was blocked by a narrow strip of ice all summer. However, this strip of ice thinned to just 30% coverage on September 25 and 26, making the Northeast Passage passable for ordinary ships on those days.

When is the last time the Northwest Passage was open?
We can be sure the Northwest Passage was never open from 1900 on, as we have detailed ice edge records from ships. It is very unlikely the Passage was open between 1497 and 1900, since this was a cold period in the northern latitudes known as "The Little Ice Age". Ships periodically attempted the Passage and were foiled during this period, and the native Inuit people have no historical tales of the Passage being navigable at any time in the past.

A good candidate for the last previous opening of the Northwest Passage was the period 5,000-7,000 years ago, when the Earth's orbital variations brought more sunlight to the Arctic in summer than at present. Prior to that, the Passage was probably open during the last inter-glacial period, 120,000 years ago. Temperatures then were 2-3 degrees Centigrade higher than present-day temperatures, and sea levels were 4-6 meters higher.

Final thoughts
If we have reached the tipping point for Arctic ice, what are the implications? I'll discuss this more in a future blog. Sea ice is very complicated, and it is not a sure thing that we have reached the tipping point. For more on the complexities of sea ice, read wunderblogger Dr. Ricky Rood's latest blog.

NASA has posted a beautiful satellite image of the Arctic ice cap at the September 15 2007 minimum, showing the open water of the Northwest Passage.

I thank Edalin Michael of the University of Michigan's School of Natural Resources and Robert Grumbine of NOAA's Sea Ice Group for their contributions to this blog.

References
Walsh, J.E and W.L.Chapman, 2001, "Twentieth-century sea ice variations from observational data", Annals of Glaciology, 33, Number 1, January 2001 , pp. 444-448.

Jeff Masters

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96. Melagoo
3:39 PM GMT on October 12, 2007
... will the Sleeping Giant ever awaken?

I wonder if we will see any more Hurricanes this year?
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95. NoNamePub
3:38 PM GMT on October 12, 2007
OK....So...lets move on to the blob s. of cuba!
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92. hurricanehanna
10:33 AM CDT on October 12, 2007
Good morning gang! I've been a little out of touch...sick aunt that I helping to take care of.

So, old 94l has a chance of getting back into the GOMEX? Unbelievable. The cool weather we are having is so deceiving - makes you almost forget we are still in H-season.
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90. strangesights
3:17 PM GMT on October 12, 2007
First and foremostly, global warming issue is not a political or even a scientific debate about proof. At the heart of the matter should be a reasoned consideration of risk management. How serious might the risk be? How likely is it to occur? If a person sees a projectile headed in your general direction out of the corner of your eye, the person ducks. People don't wait for proof that it is necessarily going to strike them, they just duck. In fact, whenever most people perceive any serious risk, they react defensively. If my crazy neighbor tells me about some serious risk, I of course will doubt him, but I also am going to look into anything that could be a serious threat. That's natural, it's smart, and it's helped many individuals survive. Even if one thinks, that there is only a 5% chance of a strong hurricane striking, a smart person prepares. Likewise, if human induced global warming only has a 5% chance of being correct, we should be preparing and working to mitigate the possible risk because it is clearly a potentially much more serious risk than a strong hurricane.
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89. stillwaiting
3:33 PM GMT on October 12, 2007
and in global warmings case I beleave we have caused a negative reacion by burning so much fossil fuels and creating so much uneeded trash
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88. patriots2007
3:33 PM GMT on October 12, 2007
At least thats flatering.
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86. stillwaiting
3:28 PM GMT on October 12, 2007
global warming= for every action there is a reaction ,you can't possibly think that humans are not having a negative impact the earth , most humans by nature are selfish and wasteful paying disregard to the envirment around them
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84. LakeShadow
3:26 PM GMT on October 12, 2007
"Global Warming is a Myth" is regurgitated propoganda. Learn to think for yourself...That type of language are unsubstantiated sloagans, created by folks with special interests.
Climate change...its happened in the past, its happening now. Its a part of the eco-system. Everything is cyclic, everything needs balance. There is concern for the unbalance of elements initiated by human population...thats the issue. Language is everything!
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83. LightningCharmer
3:29 PM GMT on October 12, 2007
The IPCC rarely mentions this in its literature but between 75% to 95% (depending on which side of the argument) of the greenhouse effect comes from this gas: WATER VAPOR.

With that said, you're going to love this article:

EPA Seeks To Have Water Vapor Classified As A Pollutant
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82. Bonedog
11:29 AM EDT on October 12, 2007
so glad I have an extensive ignore list. I am missing this cat fight folks are jabbering about
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81. NEwxguy
3:29 PM GMT on October 12, 2007
It seems like only yesterday we were talking about invests and TDs.Oh!Wait a minute it was just yesterday
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80. patriots2007
3:29 PM GMT on October 12, 2007
Honey?HMMM It is not my fault you got old,so please do not take it out on me.
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78. TampaSpin
11:28 AM EDT on October 12, 2007
Guys sorry, im going to let off some emission gases. Im starting the lawn mower in a few. I want to prepare my yard to look its best when something bad happens......lol
Member Since: September 2, 2007 Posts: 178 Comments: 20439
77. SamTeam
10:27 AM CDT on October 12, 2007
71. dfwWxDude 10:26 AM CDT on October 12, 2007
SamTeam, that blob over the Yucatan still has more energy than most of the blobs that were wish-casted so far this year.

The energy is what caught my attention, along with the size. It never really seemed to stop 'breathing'. Guess the next couple of days will tell.

I'm in SE Tex, otherwise known as Dodge the Bullet Houston. I sure don't want that bad boy headed CONUS way.

I find everyones opinions, knowledge & 'gut feeling' helpful so keep 'em coming. Where is StormW this morning?
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76. Floodman
3:28 PM GMT on October 12, 2007
1189. LakeShadow 2:48 PM GMT on October 12, 2007
Floodman, one man's "unsavory" is another's sacred ritual.... :o)
Jerry is holy to me.



Sorry, had to take a call...yes. Lake, as he is to me as well.
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71. dfwWxDude
3:07 PM GMT on October 12, 2007
SamTeam, that blob over the Yucatan still has more energy than most of the blobs that were wish-casted so far this year. Just a gut feeling, but it makes me nervous like Dean, which had so much energy just after leaving the African coast. Grew up in South Louisiana, and sometimes it is hard to shake that uncomfortable feeling of 'What's it gonna do?'
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69. Hhunter
3:20 PM GMT on October 12, 2007
global warming is a myth. There are many factors at play that effect earth temperatures. Orbit,earth axis tilt, Sun intensity, cloud cover, maybe green house gases, etc. Just look back 100,000's of thousands of years into the arctic ice record. You think this is warm, you aint seen nothing. If you think this is cold, you aint seen nothing. This may ultimately be the biggest scam every played on man kind. we shall see. That is all I will ever say on this topic...
Member Since: August 19, 2007 Posts: 0 Comments: 2973
68. Bonedog
11:25 AM EDT on October 12, 2007
no idea what your talking about Tampa. seriously
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67. NoNamePub
3:25 PM GMT on October 12, 2007
Cuba Convection refiring...that area will not die? any chance oif development?
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66. TampaSpin
11:23 AM EDT on October 12, 2007
64. Bonedog 11:23 AM EDT on October 12, 2007
I'll give you that Gumby I guess my point is that introducing excessive amounts of any substance natural or otherwise is pollution in my mind


You talking about Patriot2007's Picture.....lmao
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64. Bonedog
11:21 AM EDT on October 12, 2007
I'll give you that Gumby I guess my point is that introducing excessive amounts of any substance natural or otherwise is pollution in my mind
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62. patriots2007
3:18 PM GMT on October 12, 2007
Really,and you know that for sure.Because I do not have a web site.Some ladies are very insecure,it appears to me AND many others.Very sad in this day and age this happens.
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61. DallasGumby
3:17 PM GMT on October 12, 2007
"Introducing" CO2 into the atmosphere is not "the introduction of harmful substances or products into the environment".

But for CO2, there would be no plant life.
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60. Bonedog
11:19 AM EDT on October 12, 2007
exactly my point Tampa we have introduced pollutants into the environment that we need to clean up so that the natural checks and balances can work as they should
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59. Hhunter
3:15 PM GMT on October 12, 2007
Yea my thought on Dr. M's comment is that 94L lives as i thought it would so lets see if this is not the item that comes up into the gulf and hits texas next week. Man the computer models really point to big weather issues for texas and the midwest next week. This could be part of that equation...
Member Since: August 19, 2007 Posts: 0 Comments: 2973
58. SamTeam
10:17 AM CDT on October 12, 2007
cchsweatherman 10:16 AM CDT on October 12, 2007
Those are my thoughts. I wonder what your's are.


Due to my lack of knowledge regarding this complex subject....I don't know what my opinion is yet!

It seems, based on what I've read here, that the low will move east but I can't decide if I think it's a CONUS threat yet.
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57. TampaSpin
11:17 AM EDT on October 12, 2007
My last comment on Global warming. True we have only data for a short period of time, but we all know that many years ago the pollutiants we see today was not around. Therefore what we have created in this short time is unlike anyother period of time also.
Member Since: September 2, 2007 Posts: 178 Comments: 20439
54. LakeShadow
3:16 PM GMT on October 12, 2007
yeah, jp but the increased world population and industrialization have tipped the balance.
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52. Bonedog
11:13 AM EDT on October 12, 2007
I do feel CO2 emissions from rampant overuse of fossil fuels is pollution.

pol·lu·tion[puh-loo-shuhn]–noun
1. the act of polluting or the state of being polluted.
2. the introduction of harmful substances or products into the environment
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51. cchsweatherman
3:11 PM GMT on October 12, 2007
42. SamTeam 3:05 PM GMT on October 12, 2007
The low is drifting slowly eastwards towards the Western Caribbean, and could pop out over water on Saturday or Sunday. If this occurs, I believe the low will have enough spin to develop into a tropical depression. Steering currents are weak enough that the storm could stay trapped in the Western Caribbean for many many days, or it could loop northwestward back over the Yucatan Peninsula, arriving in the Gulf of Mexico on Monday. At that time, a trough of low pressure capable of turning the storm northwards towards Texas may arrive. This is the solution offered by the UKMET model. However, most of the computer models forecast that the low will never emerge into the Caribbean

Any thoughts/comments on this portion of Dr. M's update?


I have commented on this in the previous blog. I believe it emerged into the NW Caribbean earlier this morning. There is abundant convection and low wind shear, so I now am expecting tropical development from this low.

It will be interesting to see how this new low will affect the upcoming model runs. If I am not mistaken, I believe this surface trough is forecasted to move north over South Florida by early next week meaning that this would ride that trough. Right now, the steering currents show an overall NE flow, so that is the direction I expect this new low to take.

Those are my thoughts. I wonder what your's are.

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50. LakeShadow
3:14 PM GMT on October 12, 2007
46. DallasGumby 3:13 PM GMT on October 12, 2007
Bonedog,

My only observation about your post is that the GW debate is not about pollution -- it's about CO2 emissions. And, carbon dioxide is not a pollutant.


Dont forget methane gas emmisions from cattle ranches.
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49. TampaSpin
11:11 AM EDT on October 12, 2007
My last comment on Global warming. True we have only data for a short period of time, but we all know that many years ago the pollutiants we see today did not exist. Therefore what we have created in this short time is unlike anyother period of time also.
Member Since: September 2, 2007 Posts: 178 Comments: 20439
47. mit5000
3:12 PM GMT on October 12, 2007
shame td15 didnt become noel

)-=
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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.