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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1097. BahaHurican
9:01 AM EDT on October 13, 2007
Welcome, Shen.

Good time to join the blog, when people will not be so absorbed in what's going on that they won't even see you're there . . .

LOL
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1096. kmanislander
12:59 PM GMT on October 13, 2007
Well I just sent an e mail to Admin asking about it. Depending on what they say I will know for sure. I have another desk top that the kids use with IE6 but I think its the same. Will try that one soon to confirm
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1095. gulfbreezewill
12:59 PM GMT on October 13, 2007
Goodmorning all, does anyone have any updates on the old 94 system. Is it moving back yet toward the carribean?
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1094. hurricane23
8:59 AM EDT on October 13, 2007
When posting images its always a good option to use imageshack.
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1093. BahaHurican
9:00 AM EDT on October 13, 2007
Btn,

ALL of them???
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1092. ShenValleyFlyFish
8:57 AM EDT on October 13, 2007
1084. BahaHurican 8:51 AM EDT on October 13, 2007
You are here, Shen.

Thanks. Lurker trying to get up to speed.
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1091. BtnTx
7:56 AM CDT on October 13, 2007
Baha, My laptop shows pic properties as 740x650
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1090. BahaHurican
8:57 AM EDT on October 13, 2007
Maybe I'm not having the same problems because I'm still using IE6. I'm reluctant to change until they have some more of the bugs ironed out, and now this resolution situation of yours is making me even more leery.

LOL Maybe I'll wait until after the new year . . .
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1089. BahaHurican
8:53 AM EDT on October 13, 2007
Anyway, it seems like I will be around for a while due to the local rainy weather. I'm assuming no golf due to rain for you

Looks like this trough is the "outflow" for the rain coming out of the Caribbean. If anything comes of 94L, I really just see it training over Cuba like the rest of these clouds and busting out into the ATL that way. Unless the set up changes radically in the next 5 days, a trip into the gulf doesn't make sense to me.
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1088. kmanislander
12:52 PM GMT on October 13, 2007
Maybe I will drop an e mail to Admin because it makes images that require some resolution useless
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1087. kmanislander
12:54 PM GMT on October 13, 2007
IE7
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1086. BahaHurican
8:52 AM EDT on October 13, 2007
R u using IE6 or 7, or something else, Kman?

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1085. kmanislander
12:49 PM GMT on October 13, 2007
Baha

I see your Lili map as 500x375

It would appear that the new format has a built in image size limiter to those specs. I hate it because the resolution is awful. One or two bloggers tried telling me how to clean up the resolution but it does not work for me
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1084. BahaHurican
8:51 AM EDT on October 13, 2007
You are here, Shen.
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1083. BahaHurican
8:49 AM EDT on October 13, 2007
I'd size it down to 600. Some people have problems w/ pics over that due to small screen size.

Pity we can't all use the pics that size though. The definition is so much better. . .
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1082. ShenValleyFlyFish
8:40 AM EDT on October 13, 2007
test
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1081. BahaHurican
8:46 AM EDT on October 13, 2007
Go up to the map of Lili that I posted. That's showing as width=525 for me.

However, your pic of former 94L is supposed to show as 800, which would stretch the blog, but it's not doing so.
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1080. kmanislander
12:46 PM GMT on October 13, 2007
No I deliberately did not to see if it would stretch the blog for those viewing it. Trying to see if the problem is my computer. Do I need to size it down ?
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1079. kmanislander
12:45 PM GMT on October 13, 2007
No Baha I see your image as 500x439
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1078. BahaHurican
8:44 AM EDT on October 13, 2007
The pic u just posted has width=650.

Did u specify a size?
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1077. kmanislander
12:44 PM GMT on October 13, 2007
I just posted that last image without doing any sizing at all. Do you all see it as 500x375 ?
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1076. BahaHurican
8:43 AM EDT on October 13, 2007
Kman,

I just posted that same image of yours at its full size (640x480) and it is displaying that way for me.

I always use the [img src=] code rather than the image button, though.
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1075. kmanislander
12:43 PM GMT on October 13, 2007
Easy to see where the low is with this image

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1074. BahaHurican
8:41 AM EDT on October 13, 2007
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1073. IKE
7:40 AM CDT on October 13, 2007
I've never had any problems editing. It usually applies it right away...a few times I've had to refresh.

Not sure on the image size dilemma.
Member Since: June 9, 2005 Posts: 23 Comments: 37860
1072. kmanislander
12:37 PM GMT on October 13, 2007
Have we ever concluded for sure whay it is we can no longer post images larger than 500x375 which is the automatic limit of this new blog format ? And the other thing is I find that when I click to modify my post it "flicks" back to the post and then I have to click again before I can make the text change
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1071. IKE
7:38 AM CDT on October 13, 2007
It needs to be put back up as an invest.....
Member Since: June 9, 2005 Posts: 23 Comments: 37860
1070. hurricane23
8:36 AM EDT on October 13, 2007
Interesting cyclonic spin going on around the NW caribbean.Could it get tagged?Possible.
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1069. kmanislander
12:36 PM GMT on October 13, 2007
I guess it sneaked off to the E when the NHC was not looking LOL
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1068. IKE
7:35 AM CDT on October 13, 2007
Thanks for posting that KMAN....I'm keeping an eye on it........
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1067. kmanislander
12:32 PM GMT on October 13, 2007
Good morning all

Hi Ike

the QS pass shows a clearly defined surface low at 18N 85W, and not 87 as stated in the TWD

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1066. IKE
7:07 AM CDT on October 13, 2007
aubiesgirl 7:01 AM CDT on October 13, 2007
what's the intensity look like?


Intensity for rain is improving...for a tropical system....maybe a nice breeze!
Member Since: June 9, 2005 Posts: 23 Comments: 37860
1065. TerraNova
8:03 AM EDT on October 13, 2007
The drought outlooks indicates some improvement in Florida and the NE Gulf...but it looks like the interior SE won't be getting better any time soon.

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1064. IKE
7:01 AM CDT on October 13, 2007
aubiesgirl 7:01 AM CDT on October 13, 2007
or we get another TD10..lol


Yeah...a tenth of an inch of rain...

It's just bad all over the eastern SE.
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1063. aubiesgirl
12:01 PM GMT on October 13, 2007
what's the intensity look like?
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1062. aubiesgirl
12:00 PM GMT on October 13, 2007
or we get another TD10..lol
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1061. IKE
6:59 AM CDT on October 13, 2007
aubiesgirl 6:59 AM CDT on October 13, 2007
well like i said yesterday..I know we need it..just man I hate the humidity and heat...so what's the time frame on this thing


Middle to end of the next work week.

Now watch...we won't get a drop.
Member Since: June 9, 2005 Posts: 23 Comments: 37860
1060. aubiesgirl
11:58 AM GMT on October 13, 2007
well like i said yesterday..I know we need it..just man I hate the humidity and heat...so what's the time frame on this thing?
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1059. IKE
6:57 AM CDT on October 13, 2007
aubiesgirl 6:56 AM CDT on October 13, 2007
Ike?..could we be getting some rain...lol...94L?...lol


I hope so...and yes, we could be.
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1058. TampaSpin
7:53 AM EDT on October 13, 2007
centered at Latitude= 16.40° N Longitude= 87.55° W
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1057. IKE
6:57 AM CDT on October 13, 2007
From the TWD.......

Caribbean Sea...
a persistent 1005 mb low in the NW Caribbean along the coast of
the Yucatan just N of Belize near 19n87w with a surface trough
extending NE across central Cuba into the W Atlc. Scattered
showers/thunderstorms are NW of a line from Honduras near 16n85w
across Cuba near 20n77w but does not include the Yucatan
Channel. An upper high is situated between E Cuba and Jamaica
near 19n78w extending a ridge axis NE into the W Atlc and SW to
the coast of Honduras enhancing the activity above. Low level
and upper level convergence is generating some scattered showers
and possible isolated thunderstorms across the SW Caribbean S of
12n.
Member Since: June 9, 2005 Posts: 23 Comments: 37860
1056. aubiesgirl
11:53 AM GMT on October 13, 2007
Ike?..could we be getting some rain...lol...94L?...lol
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1055. IKE
6:52 AM CDT on October 13, 2007
The town I live in Defuniak Springs, FL....the last day that had over 1 inch of rain during it...was July 20th!

That's way too dry for this area.

I'm wishcasting a 3-5 inch rain event!
Member Since: June 9, 2005 Posts: 23 Comments: 37860
1054. TampaSpin
7:49 AM EDT on October 13, 2007
Wow the 1k pic really shows a well defined LLC IMO.Link
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1053. BahaHurican
7:44 AM EDT on October 13, 2007
There was more than one Lili. There were also Lili's in 1984, 1990 and 1996.

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1052. BahaHurican
7:24 AM EDT on October 13, 2007
Good morning.

Light rain here, looks like it's been going on for a couple hours and appears there has been at least some wind, since some of the flowers in my mother's garden are lying flat this morning.

Looking at the satellite imagery, it seems we're in for a wet day.
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1051. gulfcoastdweller
6:36 AM CDT on October 13, 2007
hummm for some reason I thought she was in late Oct.... I just remember dog show in La, outdoors on grass, soon to become a lake, lots of wet ppl and muddy dogs......happy to be home, and making up my mind to only go to covered horse arenas for dog shows from that point on!

it was a mess and it seemed to never stop raining!I think it was the Baton Rouge area
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1050. TampaSpin
7:39 AM EDT on October 13, 2007
i just want a slow moving storm to come across the state and fill my fishing holes up. It is really bad at the Big "O" right now.
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1049. Weather456
7:41 AM AST on October 13, 2007
I think folks are talking about a path...not a strength compared to those monsters.

ok..i catch it
Member Since: July 24, 2005 Posts: 407 Comments: 19076
1048. hurricane23
7:36 AM EDT on October 13, 2007
opal at one time had winds of 150mph as it moved over the loop current in the GOM.I chased that storm back in 95 and actually was able to record wind gusts in excess of 100mph.Thankfully to some windshear things looked somewhat better as the pressure begin to rise 7-8 hours before landfall. Adrian

The small eye was something to see.About 6 miles.
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1047. IKE
6:39 AM CDT on October 13, 2007
Weather456 6:38 AM CDT on October 13, 2007
I agree h23...first it was wilma, now opal when it reaches..or if it reaches the gulf it will be Katrina


I think folks are talking about a path...not a strength compared to those monsters.
Member Since: June 9, 2005 Posts: 23 Comments: 37860

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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.