Arctic Sea Ice Volume at record low.

BenBurch said:
Note that it is now THREE Standard Deviations from the trend line... I hope not for long.
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It appears from the graph that 1982 was more than 2, but less than 3, SD's.

Of course the decline was never going to approach linear towards the end. Which is what we are towards. The change is quite evident since 2005 at least.
 
Hindmost said:
Can you please elaborate on the source of the data. If it is satellite data, then 3 years is not significant enough to even develop a trend and SD.

glenn
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I think he's inspired the trend-line on the graph, which shows 1 and 2 SD's. 1982 was more than 2 SD's, which in an integral world would be 3. Or possibly 4.
 
BenBurch said:
There we go! As Capel points out, not as much impact then given that there was a LOT more ice volume.
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Oh, so the latent heat of approximately similar volumes of sea ice has changed in the intervening years?

I see.
 
BenBurch said:
If you saw what Canada has for a Navy, you'd think so.
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Don't knock the Canadian Navy. They saved our ass in WW2, we wouldn't have won the Battle of the Atlantic without them. The third largest navy in the world by 1945. They've done it before and can do it again.

The economic and (therefore) strategic implications of a navigable Arctic Ocean are ... a fascinating subject for conjecture :).
 
macdoc said:
I guess your imagination is limited..\As a polar bear the McDonald's is closing too early

http://www.conservationmaven.com/fr...ed-with-reduced-polar-bear-size-and-repr.html

Species can adapt to changes over long time......not our anthro accelerated habitat changes

ONE severe sea ice loss event could devastate populations dependent on sea ice access.

Now your "imagination" is not required...you have information to understand the point.....the rest is up to you :garfield:
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You have zero data with which to establish the limits of my imagination, so I suggest you limit your comments to things with which you do have data ..

I'm still waiting for the ' scary ' part ..
 
Skeptical Greg said:
You have zero data with which to establish the limits of my imagination, so I suggest you limit your comments to things with which you do have data ..

I'm still waiting for the ' scary ' part ..
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I think you'll be waiting a very long time as its obvious to everybody else.

Seriously, if you don't look at the data and realize that something significant is happening in the Arctic, you don't comprehend what it means.
 
BenBurch said:
No, but the dynamics are different now; That was unlikely then to cause immense leads of dark water to soak up more heat. Now that is very likely the result.
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Ben, do you have a reference regarding differences in dynamics?
 
Wangler said:
Ben, do you have a reference regarding differences in dynamics?
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Not handy. But its basic physics. As you can see from the extent diagram just posted, we are losing area at the same time as we are having a volume excursion. Loss of area means dark water. Water is well-known to absorb more heat than ice does; Ice is reflective. The result is obvious. Back in the early 80s, if you lost ice volume, there was SO much more ice that it just spread thinner and there was not the formation of leads as there is now.

As you can see, in 1980, there was a lot more area than now;

http://igloo.atmos.uiuc.edu/cgi-bin/test/print.sh?fm=06&fd=02&fy=1980&sm=06&sd=02&sy=2010
 
BenBurch said:
I think you'll be waiting a very long time as its obvious to everybody else.

Seriously, if you don't look at the data and realize that something significant is happening in the Arctic, you don't comprehend what it means.
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Where did I say it wasn't significant; as to what it means, it means different things to different people.. Some good, some bad.

If it's ' obviously ' scary , then you should be able to articulate why.
 
macdoc said:
Better yet, articulate why it's not "scary" using evidence. Since you introduced "scary" then you should be able to easily articulate what is or is not "scary". The onus is on you as you introduced the term.
Don't ask Ben to explain your limitations....
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This

I can't find a single reference to anyone dying of heat stroke in the Arctic. The real danger is dying of exposure wandering around on that sea ice.

In the worst case scenario those scrawny polar bears are easier to catch and skin if you do get stranded. ;)

More to the point, the fact that the volume of ice has changed so much in such a short time is unusual, but not particularly "scary". The loss of ice in itself doesn't provoke fear, it's the people claiming that it's "scary" that does.

The economic advantage of having the North West passage open to navigation isn't "scary" at all. There are many Canadians who will benefit from the delivery of cargo that would otherwise be impossible or extremely expensive.
 
CapelDodger said:
Don't knock the Canadian Navy. They saved our ass in WW2, we wouldn't have won the Battle of the Atlantic without them. The third largest navy in the world by 1945. They've done it before and can do it again. ---
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I think we still have the same navy.
 
3bodyproblem said:
This

I can't find a single reference to anyone dying of heat stroke in the Arctic. The real danger is dying of exposure wandering around on that sea ice.

In the worst case scenario those scrawny polar bears are easier to catch and skin if you do get stranded. ;)

More to the point, the fact that the volume of ice has changed so much in such a short time is unusual, but not particularly "scary". The loss of ice in itself doesn't provoke fear, it's the people claiming that it's "scary" that does.

The economic advantage of having the North West passage open to navigation isn't "scary" at all. There are many Canadians who will benefit from the delivery of cargo that would otherwise be impossible or extremely expensive.
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The potentially 'scary' part of it is that if this particular short-term trend continues it will mean that the arctic ice is responding to polar temperature changes at a faster rate than anticipated. This will have knock ons with albedo changes, Greenland ice-loss, and hence sea-level change. The effects will still be drawn out over a timescale of decades though.
 
"Arctic Ice at Low Point Compared to Recent Geologic History"

"The ice loss that we see today -- the ice loss that started in the early 20th Century and sped up during the last 30 years -- appears to be unmatched over at least the last few thousand years," said Leonid Polyak, a research scientist at Byrd Polar Research Center at Ohio State University. Polyak is lead author of the paper and a preceding report that he and his coauthors prepared for the U.S. Climate Change Science Program.
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http://www.sciencedaily.com/releases/2010/06/100602193423.htm
 
Mikemcc said:
The potentially 'scary' part of it is that if this particular short-term trend continues it will mean that the arctic ice is responding to polar temperature changes at a faster rate than anticipated. This will have knock ons with albedo changes, Greenland ice-loss, and hence sea-level change. The effects will still be drawn out over a timescale of decades though.
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Again, not an ideal situation and not necessarily a "good" thing, but when we start using terms like "scary" to define the yet unknown we border on fear mongering.

In this case however, I think the data could be considered "alarming". This is a considerable departure from baseline and certainly could be viewed as an "extreme" weather event.
 
macdoc said:
Better yet, articulate why it's not "scary" using evidence. Since you introduced "scary" then you should be able to easily articulate what is or is not "scary". The onus is on you as you introduced the term.Don't ask Ben to explain your limitations....
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Uhhh, check again ...


Almo said:
That's kind of scary, actually.
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3bodyproblem said:
Again, not an ideal situation and not necessarily a "good" thing, but when we start using terms like "scary" to define the yet unknown we border on fear mongering.

In this case however, I think the data could be considered "alarming". This is a considerable departure from baseline and certainly could be viewed as an "extreme" weather event.
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This graphic puts the data into some perspective imo, at least in relation to the modeling. It is yet another indicator that the modeling, far from being "alarmist" as some have tried to make out, is actually way too conservative.

http://secure90.elinuxservers.com/~projectg/wp-content/uploads/2009/11/arctic-sea-ice1.jpg
 
bit_pattern said:
This graphic puts the data into some perspective imo, at least in relation to the modeling.
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Would you have an attribution with that graph? Is there a paper to go with? Looks like it would be interesting to read. Thanks!
 
Dancing David said:
There is a big difference in the farther out you go from an SD, and the current volume is much lower.

Close by what standard? :)
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By my calibrated eye.

:)

By looking at the graph of the sea ice model output, I see about 3,500 km^3 less than the trend in 1982, and about 4,400 km^3 less than the trend currently.

These numbers are close, especially when talking about model output, calibrated and validated or not.

If I interpret the data correctly, the trend was at ~24,500 km^3 in 1982; and about 16,000 km^3 this year. Now, the deviation as a percentage of the trend at each time point is much greater now than it was in 1982.

I don't know if that is unusual or if it is to be expected as the ice volume slowly decreases over time.

The whole point of my initial muddled posts was to point out that the difference from the anomaly was also large in 1982.

Now in terms of SD, remember:

I think that the SD that I can determine from the graph is about 1,400 km^3

Fraction Number of Standard
of Data Deviations from Mean

50.0% .674
68.3 1.000
90.0 1.645
95.0 1.960
95.4 2.000
98.0 2.326
99.0 2.576
99.7 3.000

3,500 km^3 is about 2.5 SD, or about 98.5%. 4,400 km^3 is about 3.1 SD, or about 99.8%. So, about 1.5% of the data will exceed the 1982 anomaly deviation, and about 0.2% of the data will exceed the current anomaly deviation.

This is assuming a normal distribution, which seems like a valid assumtion for this modelled data set.

If we were talking differences between say 1SD and 3SD, I would call that a "big difference".
 
Thanks, Pixie,

I think you are right.

Looks like good reading material for my breaks today!
 
That paper that Pixie posted also seemed to make some sense when briefly discussing the reason for Antarctic ice not being lost like Arctic ice.
 
Skeptical Greg said:
You have zero data with which to establish the limits of my imagination, so I suggest you limit your comments to things with which you do have data ..

I'm still waiting for the ' scary ' part ..
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And we're still waiting for you to say anything substantial at all. Not with bated breath, obviously. Life's short enough as it is.
 
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