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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547. pablolopez26
8:23 PM GMT on October 12, 2007
so final numbers to me will say

16 storms, 6 hurricanes, 2 majors


Ill be serving your crow medium well... :) Your calling for 2 more "Named" storms and 2 of those becoming cat hurricanes... I dont know man... I dont see it happening right now...
545. seflagamma
4:23 PM AST on October 12, 2007
503. tornadofan 4:02 PM AST on October 12, 2007
This look scary to anyone?



is that what I think it is??? and someone else posted a model showing landing south of Tampa??? what is going on here? we have a fishing trip planned for the 20th here in SE Fla and don't want any bad weather! LOL

Cattle, LOL.. anything below 80 degrees is "cold" to me! LOL been here since '79 and my blood has thinned out a lot!
Member Since: August 29, 2005 Posts: 297 Comments: 40881
544. weathers4me
8:25 PM GMT on October 12, 2007
Are they talking about the sleeping Giant again?
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543. weathers4me
8:23 PM GMT on October 12, 2007
jp: good point. well said.
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542. tropicalweatherdummy
8:24 PM GMT on October 12, 2007
Floodman, I said the same thing.
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540. Floodman
8:19 PM GMT on October 12, 2007
531. tropicalweatherdummy 8:19 PM GMT on October 12, 2007
http://www.ahtfund.org/en/category/index/

enjoy. This should work :)



Great "Engrish"!
Member Since: August 2, 2006 Posts: 10 Comments: 9922
539. amazinwxman
8:21 PM GMT on October 12, 2007
Well Youradjuster when something tropical is happening let us know so we can all discuss it.
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537. amazinwxman
8:20 PM GMT on October 12, 2007
New Drought updates come out on Thursdays here and we in NC are in Extreme drought now with no sight of rain anytime soon.
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536. zoomiami
8:17 PM GMT on October 12, 2007
Gamma's right - no cooler air here, very humid - I would love a day or two just without the humidity.
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535. youradjuster
8:20 PM GMT on October 12, 2007
I thought this blog was supposed to be about the tropics.
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534. aubiesgirl
8:14 PM GMT on October 12, 2007
Aubie, we had severe drought conditions here in TX. Very troubling. Even had US Dept of Ag offer tiny help for ranchers having to subsidize water, feed, sell off stock. Until this year, record rains. The drought lasted 3 years. Don't know if this heavy rain in spring will continue through next year. But nature has a way of correcting its extremes.

Well this has definitly been a summer of extremes for us..record breakin temps..heat index in the 110s ..no rain..huge def..I know we need the rain badlly. We haven't been put on water restrictions thank god..But man after that hot summer this wonderful fall weather..is like ..well breath of fresh air..AC turned off..windows open it's lovely!
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533. NEwxguy
8:19 PM GMT on October 12, 2007
530. IKE 8:19 PM GMT on October 12, 2007
Gamma, Bless your heart. Our evenings are getting cold enough that I will have to bring out the long britches soon.

The first time I read that, I didn't see the "r" in britches!

lol,your really looking for trouble!
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531. tropicalweatherdummy
8:19 PM GMT on October 12, 2007
http://www.ahtfund.org/en/category/index/

enjoy. This should work :)
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530. IKE
3:18 PM CDT on October 12, 2007
Gamma, Bless your heart. Our evenings are getting cold enough that I will have to bring out the long britches soon.

The first time I read that, I didn't see the "r" in britches!
Member Since: June 9, 2005 Posts: 23 Comments: 37858
529. cattlebaroness
8:14 PM GMT on October 12, 2007
Gamma, Bless your heart. Our evenings are getting cold enough that I will have to bring out the long britches soon. And a camp fire, but that serves to burn all the feed bags as well as the wood.
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528. NEwxguy
8:14 PM GMT on October 12, 2007
end of Dec and Jan and early Feb are our "cold" months .... well cold for me...most folks call it pleasant! LOL

I'm glad you corrected yourself,those months here in Massachusetts qualify as cold months.
shiver just thinking about whats coming./
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527. IKE
3:16 PM CDT on October 12, 2007
From the long-term discussion from NO,LA.......

Another factor...which
has been discounted for now...but is Worth mentioning...is the
development of a tropical wave over the southern Gulf of Mexico
from a broad area of low pressure currently over the Yucatan
Peninsula. Both the GFS and European model (ecmwf) try to develop a weak system in
the central Gulf early next week...but the timing and exact track
of this low is highly uncertain.
Member Since: June 9, 2005 Posts: 23 Comments: 37858
526. seflagamma
4:10 PM AST on October 12, 2007
459. cattlebaroness 3:42 PM AST on October 12, 2007

Back to weather, gamma, what is considered cool weather in Fl? I am in TX and the days are still hot, but evenings are hitting low 60's, high 50's. Feels like fall.
Action: | Ignore User



Cattle,
sorry about that, I am at work so I come and go a lot when lurking or posting.
Well, I live in SE Florida, Ft Lauderdale area and we are still very much summer. Been in high 80's with high humidity...heat index still high 90's. Will be that way for a few more weeks then may cool down to low-mid 80's for a few days.

end of Dec and Jan and early Feb are our "cold" months .... well cold for me...most folks call it pleasant! LOL
Member Since: August 29, 2005 Posts: 297 Comments: 40881
525. Floodman
8:11 PM GMT on October 12, 2007
Baroness, that's what it's all about...the climate trying to find equilibrium...
Member Since: August 2, 2006 Posts: 10 Comments: 9922
524. pablolopez26
8:11 PM GMT on October 12, 2007
We are at 13 named storms 4 Hurricane and 2 majors... I think thats pretty much in line with what was being called for JP... Your going to hate me for saying this, but i say 14 named storms 5 Hurricanes and 2 major... Is my call...
523. weatherboyfsu
8:11 PM GMT on October 12, 2007
I figured that i would light a fire under some of yall.........its boring in here
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521. cattlebaroness
8:08 PM GMT on October 12, 2007
Aubie, we had severe drought conditions here in TX. Very troubling. Even had US Dept of Ag offer tiny help for ranchers having to subsidize water, feed, sell off stock. Until this year, record rains. The drought lasted 3 years. Don't know if this heavy rain in spring will continue through next year. But nature has a way of correcting its extremes.
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520. Floodman
8:09 PM GMT on October 12, 2007
517. MarcKeys 8:09 PM GMT on October 12, 2007
Looks like the season is coming to a close and we are spared again, thank goodness.

Florida Keys Fishing



Outstanding...a fishing ad!
Member Since: August 2, 2006 Posts: 10 Comments: 9922
518. aubiesgirl
8:09 PM GMT on October 12, 2007
aubiesgirl 3:05 PM CDT on October 12, 2007
could be Ike..man I know we need the rain..but I sure like the temps

It's not gonna last...by the early/mid part of next week, the humidity and bad hair days will return.
Action: | Ignore User

yea I heard that rumor too!
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516. IKE
3:07 PM CDT on October 12, 2007
aubiesgirl 3:05 PM CDT on October 12, 2007
could be Ike..man I know we need the rain..but I sure like the temps


It's not gonna last...by the early/mid part of next week, the humidity and bad hair days will return.
Member Since: June 9, 2005 Posts: 23 Comments: 37858
514. IKE
3:05 PM CDT on October 12, 2007
Long-term from Tampa........


"Long term (sun night-fri)...upper ridging over the region to
begin period while surface high center over Hatteras early to slide
into the west Atlantic. GFS has now made sudden change in next weeks
solution producing significant precipitation by middle week. Will keep
forecast fairly consistent and wait for better continuity with
other long range models before buying off on this.
Mainly slight
chance probability of precipitation throughout and have only nudged probability of precipitation up to 30 percent
Wednesday. Temperatures around climatology."
Member Since: June 9, 2005 Posts: 23 Comments: 37858
513. aubiesgirl
8:06 PM GMT on October 12, 2007
TD15 is hitting some serious shear soon..I can't imagine it becomming a TS
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512. cattlebaroness
8:03 PM GMT on October 12, 2007
Will old 94 get the name Noel or TD15? Then 94 would be Olga?
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511. aubiesgirl
8:04 PM GMT on October 12, 2007
could be Ike..man I know we need the rain..but I sure like the temps..
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510. NEwxguy
8:03 PM GMT on October 12, 2007
models sure want to spin something up either 94l or something new next week.
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508. IKE
3:02 PM CDT on October 12, 2007
Long-term from Tallahassee...

"Long term...dry pattern continues through Tuesday before deeper
moisture begins to return. 12z guidance indicating a possible
tropical surge of moisture by Wednesday and Thursday which would
increase probability of precipitation across the area.
This solution much wetter than
previous days so will hold off on changes to extended and wait for
better model consensus."..........


94L??????????????????????
Member Since: June 9, 2005 Posts: 23 Comments: 37858
507. aubiesgirl
8:03 PM GMT on October 12, 2007
Seriously though...94L?..
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506. cattlebaroness
7:59 PM GMT on October 12, 2007
Hanna thanks. But my cows are pretty cute. And my goats, just not my billy. He is completely disgusting.

So we have just one system to watch for the next few days? Over or near the Yucatan?
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505. Hhunter
7:59 PM GMT on October 12, 2007
lets get back to the tropics. afterall temperatures over 80 degrees in the gom in early october must be due to global warming. So it is safe to say that Noel to be will be a global warming induced event.... lol
Member Since: August 19, 2007 Posts: 0 Comments: 2973
503. tornadofan
7:46 PM GMT on October 12, 2007
This look scary to anyone?

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502. NEwxguy
7:59 PM GMT on October 12, 2007
493. jphurricane2006 7:57 PM GMT on October 12, 2007
oh wait aubiesgirl dont bring up making a fire outside, you will be accused of selling porn lol

lol,one has to proof read a statement before posting to make sure it can't be taken the wrong way.
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501. aubiesgirl
8:01 PM GMT on October 12, 2007
ok so back on topic..lol...so uh 94L?..got a lil spin I hear?
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499. pablolopez26
7:55 PM GMT on October 12, 2007
Updated: 1:53 PM CDT
Observed at Houston, Texas
Temperature 82 °F / 28 °C
Humidity 44%
Dew Point 58 °F / 14 °C
Wind Variable at 5 mph / 7 km/h / 2.1 m/s
Conditions Partly Cloudy

So nice and cool here in Houston... It was so awesome this morning, cool and calm... Wonderful!! It was about 63 degrees this morning...
497. IKE
2:58 PM CDT on October 12, 2007
Here is the 12Z ECMWF and sure nuff...it is in line with the GFS 12Z run....

Link


The 12Z CMC is about the same.
Member Since: June 9, 2005 Posts: 23 Comments: 37858

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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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