Fabled Northwest Passage begins to re-freeze

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

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.

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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747. kmanislander
11:11 PM GMT on October 12, 2007

We are approaching the secondary peak in oct. The next 10 days will tell the tale and I also expect a Nov surprise with the strong La Nina.
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746. TampaSpin
11:11 PM GMT on October 12, 2007
Kman--keep a chainsaw with ya...lol
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10:54 PM GMT on October 12, 2007
the effects are only just beginning fatpenquin watch, what i find the stangest the most is how all lakes rivers especial in the artic drying up even great lakes superior in particular i beleive the effects are gonna be far more than imagineable we are on a runaway train effect in which the point of no return has been reach and no matter what we try or not try its not gonna matter for we will face what we have chosen for ourselves
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743. kmanislander
11:10 PM GMT on October 12, 2007
Yea Tampa

The trees kept getting in the way of my ball though LOL
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740. Drakoen
7:10 PM EDT on October 12, 2007
You can still see the circulation here. Also notice the week steering in the Caribbean.
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738. TampaSpin
11:09 PM GMT on October 12, 2007
Kman--played that course it is awsome as hell.
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737. moonlightcowboy
11:08 PM GMT on October 12, 2007
94L may spin up again...and this time over water, I don't think it'll be so trivial, the giant may indeed awaken.

Good evening, StormW, K'man, Drakoen, Adrian, all!

Just stopping in before heading to dinner. Yeah, to say we're bust, done through is just pre-mature.
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736. kmanislander
11:07 PM GMT on October 12, 2007
Hey StormW

Tarpon Springs/Innisbrook Golf resort

Love that area. Especially the golf !
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735. icmoore
11:07 PM GMT on October 12, 2007
Good Evening StormW, Nice to see you again.
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734. kmanislander
11:04 PM GMT on October 12, 2007
Ex 94L is just barely inland by extreme NE Guatemala near the border with Honduras

It would not take much for it to slide offshore and meander around for a few days in light steering. I do not think we have seen the last of it as heavy convection is firing up just offshore the low center and sustaining the moisture in the low itself when it is drawn inland
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733. TampaSpin
11:06 PM GMT on October 12, 2007
I live in Town Country--near Alonso High School
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731. Drakoen
7:04 PM EDT on October 12, 2007
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730. TampaSpin
11:04 PM GMT on October 12, 2007
StormW--you live in Tampa also.
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729. Drakoen
7:04 PM EDT on October 12, 2007
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728. weatherboyfsu
11:01 PM GMT on October 12, 2007
Hurricane charley was bad a.....

Those squall lines that come thru were awesome.....I will never forget that day......that was a stormchasers dream day
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726. hurricane23
18:59 EDT le 12 octobre 2007
Hey Andy!

Yea everythings cool my friend...

Iam actually kinda excited as iam going tommorow to pick up my 2008 Scion at the dealer ship.

Iam tradeing in my 2000 honda and Dont recommend it to anybody as that car is one of the most stolen cars right now.That car has put me through a few heart aches.
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725. BahaHurican
6:58 PM EDT on October 12, 2007
Oooh poor Patrap. Diverticulitis is PAINFUL!

Glad to see he looks like he's feeling a bit better.
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724. CosmicEvents
10:58 PM GMT on October 12, 2007
Thanks Nash.
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723. nash28
10:58 PM GMT on October 12, 2007
Great image Adrian!!!

Hope all is well with you my friend.
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722. hurricane23
18:57 EDT le 12 octobre 2007
Animated radar GIF i caught while driving towards hurricane charley.

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721. BahaHurican
6:55 PM EDT on October 12, 2007
Anybody looking at the entire Caribbean basin (convulsed with activity) right now and still convincing themselves there will be nothing further is, well, not looking at the entire Caribbean basin.

Sure is a lot of moisture out there.
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720. nash28
10:57 PM GMT on October 12, 2007
GFDL is only run with a system currently out there.
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719. hahaguy
10:57 PM GMT on October 12, 2007
i get very excited when the weather drops down to the 50's and fall comes
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718. nash28
10:56 PM GMT on October 12, 2007
Ok guys.

Gotta run. Take care of yourselves.
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717. CosmicEvents
10:55 PM GMT on October 12, 2007
709. hurricane23 10:53 PM GMT on October 12, 2007
Its forcasted by some of the models ive looked at to go ahead and become a tropical cyclone in the next few days.Right now its 50/50
Have you seen a model that's NOT forecasting something from this low? And is the GFDL being run, or does that only get run when there's a system that it can initialize on?
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716. TropicalStalker
10:54 PM GMT on October 12, 2007
Yep, that can be bad. My grandfather has it all the time and as a child he went diving for oysters. He still works on the water and trotlines crabs for a living. I always thought that diverticulitus meant that he got sick from diving.
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715. nash28
10:55 PM GMT on October 12, 2007
Ok, where's JimRockford????

Sorry, couldn't resist!

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714. Floodman
10:55 PM GMT on October 12, 2007
Well, folks, I'm outta here for the time being...finally done at the office, and I'm about to start the weekend...
Member Since: August 2, 2006 Posts: 10 Comments: 9948
713. BahaHurican
6:53 PM EDT on October 12, 2007
PabloL, they do a post-season analysis of all the systems.
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712. nash28
10:52 PM GMT on October 12, 2007
Oh boy!!!!!

That is NOT a fun issue for Pat to be dealing with!!!!

I really wish him the best with this!
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711. Drakoen
6:54 PM EDT on October 12, 2007
yea Adrian thats what i am thinking.
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710. weatherboyfsu
10:53 PM GMT on October 12, 2007
Looks to be an interesting weekend with that area in the NW caribbean.......later
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709. hurricane23
18:52 EDT le 12 octobre 2007
Its forcasted by some of the models ive looked at to go ahead and become a tropical cyclone in the next few days.Right now its 50/50.
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708. katadman
5:50 PM CDT on October 12, 2007
icmoore, I just came from her page. Thanks.
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707. icmoore
10:51 PM GMT on October 12, 2007
His wife said diverticlitis.
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706. FatPenguin
9:00 PM GMT on October 12, 2007
Don't know why anyone would think that things are going to cool down anytime soon. We just had the least amount of summer ice in the North Pole in modern times. If you know anything about albedo effect, you'll understand how that is a longterm effect.

The Arctic Ocean just spent the summer sunning itself. It's a "tan" that's not going to fade anytime soon.
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705. nash28
10:50 PM GMT on October 12, 2007
And believe me... People weren't screwing around with Charley! Basically EVERYONE got the hell out of dodge, which was good to see.
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704. Drakoen
6:50 PM EDT on October 12, 2007
Adrian what do you think about the low exiting Belize?
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703. TampaSpin
10:48 PM GMT on October 12, 2007
Sat Dec 8, 2007 Islanders @ Lightning 7:30 PM
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702. pablolopez26
10:49 PM GMT on October 12, 2007
NHC said it was likely in one of their discussions of the storm.

So i guess this is something they talk about after the season and then the records are updated?
701. TropicalStalker
10:47 PM GMT on October 12, 2007
What is wrong with Pat? I am new to blogging on here and I have read a lot of his posts but didn't know either.
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700. nash28
10:47 PM GMT on October 12, 2007
I have to say.... The mass evacuation ahead of Charley was pretty impressive...

I lived at that time at Rocky Point (those of you from the Tampa area will know where that is).

From my apartment balcony, I was able to see HWY 60 and the mass traffic jam heading towards the Veterans and 275.

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699. hurricane23
18:48 EDT le 12 octobre 2007
All in all i dont expect anything significant from the weather just east of florida.Its actually forcasted to come back towards the state bringing some rain chances to the area.
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698. icmoore
10:42 PM GMT on October 12, 2007
katadman, This morning on WU blog reeldrlaura I saw pictures of Patrap smiling in a hopital bed. Last night somewhere I haven't looked yet tonight his wife Teresa updated his condition
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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: 9948

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Dr. Masters co-founded wunderground in 1995. He flew with the NOAA Hurricane Hunters from 1986-1990. Co-blogging with him: Bob Henson, @bhensonweather

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