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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697. Floodman
10:46 PM GMT on October 12, 2007
Me too gamma, thx...have a good one!
Member Since: August 2, 2006 Posts: 10 Comments: 9922
696. TampaSpin
10:45 PM GMT on October 12, 2007
Nash28--the worst thing was boarding up at work and at home. Put it up, take it down, put it up, take it down....lol. The first time no big deal but, by the 3rd time you was just down right pissed....lol
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695. Drakoen
6:45 PM EDT on October 12, 2007
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694. nash28
10:46 PM GMT on October 12, 2007
I had no idea Pat was sick...

This is what I get for being away:-(

My prayers are with him!
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693. seflagamma
6:46 PM AST on October 12, 2007
got to go for now. enjoy your evening!
Member Since: August 29, 2005 Posts: 298 Comments: 40890
691. seflagamma
6:45 PM AST on October 12, 2007
you're welcome. anytime I can be of help! :o)
Member Since: August 29, 2005 Posts: 298 Comments: 40890
690. BahaHurican
6:42 PM EDT on October 12, 2007
Evening everyone . . .

676. pablolopez26 10:38 PM GMT on October 12, 2007
Hey any idea why JP was telling me that TS Karen would upgraded to a Hurricane Post Season? Is that true? I was under the impression that Karen had max sustained winds of 70MPH nothing higher... Any ideas?


NHC said it was likely in one of their discussions of the storm.
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689. Drakoen
6:44 PM EDT on October 12, 2007
682. Bobbyweather 6:42 PM EDT on October 12, 2007 Hide this comment.
Drak, the low near Belize is Post-94L...


I know....
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688. katadman
5:43 PM CDT on October 12, 2007
Thanks, Gamma.
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687. nash28
10:38 PM GMT on October 12, 2007
Yeah Tampa-

2004 in a nutshell-

1) Charley- Mass evacuation for Hillsborough and Pinellas County. Scared the hell out of all of us. Charley turned right. Saved our bacon.

2) Frances- The SLOWEST and LONGEST nightmare I have ever experienced! 23hrs of TS/Hurricane conditions.

3) Jeanne- The strongest of the two that crossed over Tampa. Anger sets in. Swearing begins.
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686. seflagamma
6:43 PM AST on October 12, 2007
actually "reeldrlaura" has pictures she took of him in the hospital this morning in her blog. he looks pretty good considering what he has been thru.
Member Since: August 29, 2005 Posts: 298 Comments: 40890
685. TampaSpin
10:40 PM GMT on October 12, 2007
pressure at Belieze is at 1000.9
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684. TropicalStalker
10:41 PM GMT on October 12, 2007
Goodevening everyone, weather is quiet here in Florida. (I wish the kids were as quiet)

Looks like a mess just south of us though, judging by drakoen's weather image.
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682. Bobbyweather
6:41 PM EDT on October 12, 2007
Drak, the low near Belize is Post-94L...

I state that Dr. Masters said that Karen will most likely be upgraded to a CAT1 hurricane.
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681. seflagamma
6:41 PM AST on October 12, 2007
Hey, about Pat, I got an update from Laura this morning and she is there in NO now. He is resting comfortably but will need the surgery this time. His wife said he should be blogging soon. He must take care of himself and not make things worse.
Member Since: August 29, 2005 Posts: 298 Comments: 40890
680. katadman
5:40 PM CDT on October 12, 2007
Karen was suspected of reaching minimum Cat 1 windspeeds for just a few hours.
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679. Floodman
10:39 PM GMT on October 12, 2007
676. pablolopez26 10:39 PM GMT on October 12, 2007
Hey any idea why JP was telling me that TS Karen would upgraded to a Hurricane Post Season? Is that true? I was under the impression that Karen had max sustained winds of 70MPH nothing higher... Any ideas?



because there awas a very breif period when Karen's sustained winds were higher than that...
Member Since: August 2, 2006 Posts: 10 Comments: 9922
678. katadman
5:38 PM CDT on October 12, 2007
I don't speak Italian, but I recognize a spanish cognate at the end of that. Not very nice....
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677. Drakoen
6:40 PM EDT on October 12, 2007
The low to watch appears be the one near Belize It already has an outflow.
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676. pablolopez26
10:38 PM GMT on October 12, 2007
Hey any idea why JP was telling me that TS Karen would upgraded to a Hurricane Post Season? Is that true? I was under the impression that Karen had max sustained winds of 70MPH nothing higher... Any ideas?
675. hurricane23
18:36 EDT le 12 octobre 2007
I got some gusts with jeanne on my wind gauge of 60-70mph in miami with some rain bands.
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674. Floodman
10:37 PM GMT on October 12, 2007
664. Hhunter 10:35 PM GMT on October 12, 2007
trust me I will give up counter balancing if you can stay on topic but if gw is mentioned I will counter...much rather talk tropics



Did you not read the whole post? Not actually a GW theory, but more of a "how will the Ice Age form" theory...enough...back on the subject...what were we talking about?
Member Since: August 2, 2006 Posts: 10 Comments: 9922
673. katadman
5:37 PM CDT on October 12, 2007
Visited Patrap's blog, but the last entry was September 12.
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672. nash28
10:37 PM GMT on October 12, 2007
You really wanna screw with them, yell "vaffanculo"!!!!!

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671. TampaSpin
10:36 PM GMT on October 12, 2007
I think that was Jeanne. i may have the storms mixed up they were coming and going so damb fast. Every weekend for 4 weeks in a row we was dealing with a storm......lol
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670. Floodman
10:36 PM GMT on October 12, 2007
667. nash28 10:36 PM GMT on October 12, 2007
You want to have your neighbors look at you like you have two heads???

Stand outside and scream CAGNA!!!!!!!!



LOL...I try very hard not to yell at the sky nash...the repercussions can be far worse than the slight
Member Since: August 2, 2006 Posts: 10 Comments: 9922
669. katadman
5:35 PM CDT on October 12, 2007
Guess so, spncnewbie. Want us to tone it down?
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668. Floodman
10:34 PM GMT on October 12, 2007
658. IKE 10:32 PM GMT on October 12, 2007
18Z GFS through 168 hours...........




I hadn't noticed the other low cutting across the Straits in to SW Fl...96 hours? Looks like they see our Cayman low moving nearly due north
Member Since: August 2, 2006 Posts: 10 Comments: 9922
667. nash28
10:33 PM GMT on October 12, 2007
You want to have your neighbors look at you like you have two heads???

Stand outside and scream CAGNA!!!!!!!!
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666. TampaSpin
10:33 PM GMT on October 12, 2007
I Jeanne went right over Tampa with tropical winds of about 60mph and we had trees down everywhere.....i had no power at my home 5 days and no power at my work for 2 days and that was just a tropical storm.
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665. CosmicEvents
10:28 PM GMT on October 12, 2007
Hunter, only a fool would be 100% certain that GW is a myth, or that it's a reality.
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664. Hhunter
10:31 PM GMT on October 12, 2007
trust me I will give up counter balancing if you can stay on topic but if gw is mentioned I will counter...much rather talk tropics
Member Since: August 19, 2007 Posts: 0 Comments: 2973
663. Drakoen
6:35 PM EDT on October 12, 2007
hello Floodman...
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662. katadman
5:29 PM CDT on October 12, 2007
Nash, you and your wife must have been freaking.

A few years back, I was sleeping one night and felt water sprinkling my face. Groggily, I reached overhead to close the window to find that it was already shut! I bolted awake and started to jump out of bed when the shards started flying. One about the size of a machete blade landed flat on my thigh without cutting me. The insurance adjuster said it was straight-line winds, but I still think it was a tornado nearby. There was a barn roof in my backyard that was from a barn about a mile away.
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661. spncnewbie
10:31 PM GMT on October 12, 2007
So, I guess the discussion is i remember when...
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660. Floodman
10:32 PM GMT on October 12, 2007
Hey, Drak...
Member Since: August 2, 2006 Posts: 10 Comments: 9922
659. nash28
10:30 PM GMT on October 12, 2007
Yeah, Jeanne pissed me off! I had a screaming wife and water and glass to deal with on her birthday.

I think I swore in Italian at the top of my lungs outside in the wind and rain, and I hardly ever use Italian cuss words:-)
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658. IKE
5:31 PM CDT on October 12, 2007
18Z GFS through 168 hours...........

Link
Member Since: June 9, 2005 Posts: 23 Comments: 37858
657. Drakoen
6:31 PM EDT on October 12, 2007
Two areas of low pressure.
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656. Floodman
10:30 PM GMT on October 12, 2007
Good question, kat...has anyone heard how Patrap is doing?
Member Since: August 2, 2006 Posts: 10 Comments: 9922
655. nash28
10:29 PM GMT on October 12, 2007
Just goes to show you what a CAT1 hurricane can do....

Jeanne crossed Tampa with winds of around 85mph and just the pressure of the wind shattered the window, not a tree.
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654. Floodman
10:29 PM GMT on October 12, 2007
653. nash28 10:28 PM GMT on October 12, 2007
Jeanne damn near cut my wife with a broken bedroom window as she slept.

Hell, I even moved the bed as far away from the window as I could, then BAM!



Jeanne was my first eye...
Member Since: August 2, 2006 Posts: 10 Comments: 9922
653. nash28
10:27 PM GMT on October 12, 2007
Jeanne damn near cut my wife with a broken bedroom window as she slept.

Hell, I even moved the bed as far away from the window as I could, then BAM!
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652. Floodman
10:28 PM GMT on October 12, 2007
650. seflagamma 10:28 PM GMT on October 12, 2007
floodman,
Thanks!!!



My pleasure, gamma ; )
Member Since: August 2, 2006 Posts: 10 Comments: 9922
651. Floodman
10:27 PM GMT on October 12, 2007
Geez, hunter, give it up!
Member Since: August 2, 2006 Posts: 10 Comments: 9922
650. seflagamma
6:26 PM AST on October 12, 2007
floodman,
Thanks!!!
Member Since: August 29, 2005 Posts: 298 Comments: 40890
649. nash28
10:26 PM GMT on October 12, 2007
It wouldn't surprise me at all to have a system hit us on my birthday, which is Halloween.

Then my wife and I would be even.....

Jeanne ruined her birthday.
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648. Floodman
10:25 PM GMT on October 12, 2007
643. nash28 10:25 PM GMT on October 12, 2007
Thanks man...

Been away from the tropics all week.



I noticed I hadn't seen you in a while...people were actually asking ME questions...scary
Member Since: August 2, 2006 Posts: 10 Comments: 9922
647. katadman
5:26 PM CDT on October 12, 2007
How's Patrap doing after surgery?
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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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