Sea Ice News #36 – Arctic maximum ice extent reached – NANSEN data disagrees with NSIDC's on the claim of a tie with 2006-2007

Now we start the slow slide into the Arctic Ice Minimum, likely sometime in September.

It is important to point out that there’s a lot of ice up there, and as illustrated by the images below, the losses at ICEmax are at the periphery, not at the core.

click to enlarge

What I find curious is the fact that NSDIC’s opening statement (below) in the press release has these words: “Arctic sea ice extent” but if you look at the NSIDC provided plot above, you’ll note that they include normal lines (in orange) for areas that are outside of the Arctic circle. While perhaps a small point, it does speak to accuracy in reporting. For example, I really don’t see how sea ice off the north coast of Newfoundland can be considered “Arctic” when it doesn’t even come close to being within the Arctic Circle.

[Update: Dr. Walt Meier of NSIDC in an email agrees that the orange boundaries are “somewhat arbitrary” and has agreed to explore a  “what if” question for me. I hope to have a plot from him using Arctic circle as a boundary in a couple of weeks to see if there is any significant difference – Anthony]

It’s also important to note that this NSDIC claim only represents data from a 30 year satellite record, not the all time ice record, which is spotty and incomplete. From historical anecdotes, it appears the Arctic has gone through periods of reduced ice in the past. While NSIDC claims the maximum to be a tie with the 2006-2007 period on their plot (see their press release below), I’ll point out that NANSEN’s plot, using the same SSMI sensor platform, shows it nowhere near the 2007 value at present, though there was an intersection in the month of February:

NANSEN Artic ROOS- Sea ice extent 15% or greater - click for larger image

Source here NANSEN data (CSV file with both extent and area) download here

 

In fact, NSIDC claims the maximum was reached on March 7th, but as we see in the NANSEN plot above, the ice continues to grow as late as 3/23 when that plot was produced. This discrepancy between two organizations that use the SSMI data is curious. However, the JAXA AMSRE data does seem to support NSIDC’s claim.

More live plots are available on the WUWT Sea Ice Page

======================================================================

Here’s NSIDC’s announcement:

Annual maximum ice extent reached

Arctic sea ice extent appeared to reach its maximum extent for the year on March 7, marking the beginning of the melt season. This year’s maximum tied for the lowest in the satellite record. NSIDC will release a detailed analysis of 2010 to 2011 winter sea ice conditions during the second week of April.

map from space showing sea ice extent, continents

Figure 1. Arctic sea ice extent on March 7 was 14.64 million square kilometers (5.65 million square miles). The orange line shows the 1979 to 2000 median extent for that day. The black cross indicates the geographic North Pole. Sea Ice Index data. About the data.

—Credit: National Snow and Ice Data Center 

High-resolution image

Overview of conditions

On March 7, 2011, Arctic sea ice likely reached its maximum extent for the year, at 14.64 million square kilometers (5.65 million square miles). The maximum extent was 1.2 million square kilometers (471,000 square miles) below the 1979 to 2000 average of 15.86 million square kilometers (6.12 million square miles), and equal (within 0.1%) to 2006 for the lowest maximum extent in the satellite record.

graph with months on x axis and extent on y axis

Figure 2. The graph above shows daily Arctic sea ice extent as of March 22, 2011, along with daily ice extents for 2006, which had the previous lowest maximum extent, and 2007, the year with the lowest minimum extent in September. Light blue indicates 2011, green shows 2007, light green shows 2006, and dark gray shows the 1979 to 2000 average. The gray area around the average line shows the two standard deviation range of the data. Sea Ice Index data.

—Credit: National Snow and Ice Data Center 

High-resolution image

Conditions in context

As of March 22, ice extent has declined for five straight days. However there is still a chance that the ice extent could expand again. Sea ice extent in February and March tends to be quite variable, because ice near the edge is thin and often quite dispersed. The thin ice is highly sensitive to weather, moving or melting quickly in response to changing winds and temperatures, and it often oscillates near the maximum extent for several days or weeks, as it has done this year.

Since the start of the satellite record in 1979, the maximum Arctic sea ice extent has occurred as early as February 18 and as late as March 31, with an average date of March 6.

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Latitude

It’s also important to note that this NSDIC claim only represents data from a 30 year satellite record,
====================================================
Start your record keeping at a time when predictions were that we were going into another ice age and glaciers would soon cover us all….
……because there was too much ice
and you would hope that ice extent would go down………
….Winter max and summer min are always weather
May and Dec it all comes back together

sharper00

[snip – rant]

Joe Prins

Maybe NSDIC is a little too fast out of the gate. Winds are different from last year, so is the temperature record, so is the AO etc. Looking at the temperature trends I suspect that ice extent may continue for a day or another week.

Peter Plail

I see no mention of multi year ice or ice thickness which was deemed to be so important previously when the ice extent wasn’t following the script. From the 2007 v 2011 images that our host has shown above, the ice this year looks pretty solid.
In fact, if the Catlin expedition is going to be repeated again this year then I think they might have a straight run to the pole like BBCs Top Gear team had when they drove. The only thing likely to slow them down is the time it is going to take to drill through all that ice.

CRS, Dr.P.H.

I really don’t see how sea ice off the north coast of Newfoundland can be considered “Arctic” when it doesn’t even come close to being within the Arctic Circle.

Thanks for bringing this up, Anthony, I’ve also wondered about that. Hudson’s Bay fits into the same category.
I think we’ve built up some nice multi-year ice in the Arctic, so it will be interesting to watch this in coming months.

sharper00

“[snip – rant]”
The “rant” was a link to the to the wikipedia entry which defines the Arctic Ocean which is of course what the NSIDC tracks, not the Arctic Circle.
REPLY: Well then you are welcome to submit that again, minus the ranting that surrounded it, but I must point out that this map included in that article:
http://en.wikipedia.org/wiki/File:Arctic_Ocean_-_en.png
Does not show the coast of Newfoundland down to St. Johns as being part of it. That’s my point. And clearly, the Sea of Okhotsk is not part of the Arctic Ocean, yet NSIDC tracks “Arctic sea ice” there. Take these non-Arctic areas out, and let’s see how the true Arctic has fared over the last 30 years. – Anthony
– Anthony

HaroldW

In the charts displayed above, NSIDC presents a reference curve of an average of 1979-2000, and NANSEN uses an average of 1979-2006. In the anomaly charts on the reference page, anomalies are computed relative to a 30-year baseline 1979-2008; the period of 30 years has an unusually privileged place among baselines. I’m curious why neither institution has changed its graph to use a 30-year-long average. Has the question been asked?

jakers

“Start your record keeping at a time when predictions were that we were going into another ice age and glaciers would soon cover us all….
……because there was too much ice”
Hm, never heard that one before, that there was “too much ice” in 1979!
This looks back to 1950, and for NS, to 1810.
http://www.socc.ca/cms/en/socc/seaIce/pastSeaIce.aspx

Tim Clark

Well, the temperature in the Arctic is about 21 K below freezing. Not a lot of thawing within the Circle.

Ben Hillicoss

and so it begins….

sharper00

“Does not show the coast of Newfoundland down to St. Johns as being part of it. That’s my point. “
http://en.wikipedia.org/wiki/Arctic_Ocean#Extent is the full link I posted the first time.
Now that you’ve actually looked at the link you’ll have noted the definition is not the same as the Arctic Circle, the actual definition of what comprises the Arctic Ocean depends on what you’re talking about with different organisations using different definitions.
The NSIDC provides the answer to your question
http://nsidc.org/arcticmet/basics/arctic_definition.html
“Arctic researchers also define the Arctic region as:
The area north of the treeline (the northern limit of upright tree growth)
Locations in high latitudes where the average daily summer temperature does not rise above 10 degrees Celsius”

There is nothing incorrect or “inaccurate” as noted above.
REPLY:The definition is nebulous, and that’s part of the problem. You say nothing incorrect or “inaccurate”….except that treelines are not relevant to sea ice and the Sea of Okhotsk is not the Arctic Ocean. Rationalization won’t make it so. – Anthony

Gerald Machnee

Peter Plail says:
March 24, 2011 at 1:20 pm
***In fact, if the Catlin expedition is going to be repeated again this year then I think they might have a straight run to the pole like BBCs Top Gear team had when they drove. ***
Top Gear did not go to the geographic North Pole – They went to the magnetic pole.

Latitude

jakers says:
March 24, 2011 at 1:40 pm
===============================
jakers, can you not look at the chart you posted and see that the 70’s and 1980 were the highest sea ice in the Arctic?
..and that 2000 has a lot more ice than 1950?
Look at the chart you posted and figure out what happens when you start at 1980 and consider 1980 “normal”
http://www.socc.ca/cms/en/socc/seaIce/pastSeaIce.aspx

batheswithwhales

Hm..I are we sure that maximum has been reached yet. 2010 peaked at the very end of March/early April, and Norsex seems to be ticking up.

Gerald Machnee says:
March 24, 2011 at 2:33 pm

Top Gear did not go to the geographic North Pole – They went to the magnetic pole.

From there, there will pretty much always be ice all the way to the actual pole, so they could just as easily have reached that. The point was made that there is, in fact, plenty of ice. So much ice that you can drive all the way to the pole (either one). And it was made very, very, well!
It is still something I love to pint out to those who yell shrilly about the Arctic being ice free in [take your pick, Big Al says 3 more?] years.

David

‘Ice-a, ice-a, baby…’
Sorry, folks – just having a senior moment…..!

Mike

@ Peter Plail asked about ice thinkness. Here is volume info:
http://psc.apl.washington.edu/wordpress/research/projects/arctic-sea-ice-volume-anomaly/

George E. Smith

See I no longer have to go to Stonehenge to find out if it is Spring; izzat the First Point of Aries or some such Salem Witch monicker. I just have to come to WUWT to see if the great ice vanish has started. Here we all go again Anthony; must be a year since we last did this !

Luther Wu

Just looking at the AMSRE (IJIS) graphic, the extent is apparently > 2005 and 2007 while above the extent for 2006.
http://www.ijis.iarc.uaf.edu/seaice/extent/AMSRE_Sea_Ice_Extent_L.png

Mike

@ Tim Clark says: March 24, 2011 at 1:45 pm “Well, the temperature in the Arctic is about 21 K below freezing. Not a lot of thawing within the Circle.”
I am not sure, but I think some of the melting is from warmer ocean water below.

George E. Smith

“”””” Tim Clark says:
March 24, 2011 at 1:45 pm
Well, the temperature in the Arctic is about 21 K below freezing. Not a lot of thawing within the Circle. “””””
Well how in the hell did the Arctic get to 21 K; and you are correct; that certainly is below freezing.
Are you sure you don’t mean -21 deg C ??

George E. Smith

“”””” CRS, Dr.P.H. says:
March 24, 2011 at 1:23 pm
I really don’t see how sea ice off the north coast of Newfoundland can be considered “Arctic” when it doesn’t even come close to being within the Arctic Circle.
Thanks for bringing this up, Anthony, I’ve also wondered about that. Hudson’s Bay fits into the same category. “””””
Well I may be an old fuddy duddy; but “The Arctic” and the “Arctic Circle” are not one an the same; synonyms for each other.
When I went to shool, , “The Arctic” was anything North of +60 deg Latitude. The “Arctic circle” is a menagery lion that runs around the earth right where the sun never rises (gometrically) in winter, and it wanders around in Latitude as the earth’s polar axis shifts. The “Arctic” however always stays put at +60 deg Latitude.
If you would like to dispute that, then stop calling the “Antarctic Peninsula” the “Antarctic”.

Andrew30

Here is my forecast
2011 Minimum Extent:
September 17th 2011.
6.23 M km^2 (JAXA’s AMSR-E 15%)

Gneiss

Anthony writes,
“What I find curious is the fact that NSDIC’s opening statement (below) in the press release has these words: “Arctic sea ice extent” but if you look at the NSIDC provided plot above, you’ll note that they include normal lines (in orange) for areas that are outside of the Arctic circle. ”
I’m surprised that you find this curious. I don’t know of any Arctic ice researchers who define “Arctic” as “north of Arctic Circle.” Do you? Perhaps WUWT could lead the way by creating the first dataset of sea ice extent exclusively within the Arctic Circle, and see what that tells us.
“In fact, NSIDC claims the maximum was reached on March 7th, but as we see in the NANSEN plot above, the ice continues to grow as late as 3/23 when that plot was produced.”
(Nansen was a man, not an acronym.) I tend to view NSIDC data as most definitive, and credit their “claim” of a May 7 max. That roughly agrees with the peaks not only for IJIS but also Uni Bremen and Cryosphere Today. But each research group uses different algorithms, so there are bound to be some differences in the results. Do you have a reason for preferring Arctic ROOS when they disagree? Will that preference be followed through the rest of the season?
REPLY: Walt Meier from NSIDC has agreed to provide a plot, let’s see what it says, isn’t that what science is all about, exploring new ideas? As for your objection to my use of NANSEN, I made no claims of it being an acronym, I only capitalized it to make sure readers knew clearly what it was. I’m well aware of the history of his travels.
You also seemed to have conveniently missed the sentence I made about JAXA AMSRE (which IS an acronym). But, since your purpose here is (and always has been) to denigrate from the comfort of anonymity, you go “Gneiss”.
– Anthony

Gneiss

Luther Wu writes,
“Just looking at the AMSRE (IJIS) graphic, the extent is apparently > 2005 and 2007 while above the extent for 2006.”
That is correct, if you mean that IJIS max this year is *below* 2005 and 2007, while still above 2006.

mjk

Sharperoo,
Don’t get caught in Anthony’s school boy argument about the definition of the “Arctic”. The point is all the measures, yet again, point to very low ice extent for this time of year. Anthony is raising a red herring to divert our attention from this fact.
MJK
REPLY: well whether you think it is “schoolboy” or not, in an email exchange just now, Walt Meir of NSIDC thought it an interesting enough question to take me up on my suggestion and offer a plot, he’s going to be traveling so it me be a couple weeks. I’ll present it here when he does. – Anthony

sharper00

“The definition is nebulous, and that’s part of the problem. “
No it isn’t, all that matters is that the area under examination is consistent. That’s it. Precisely what defines “The Arctic Ocean” is no doubt an interesting aside but ultimately it’s irrelevant just as if you were to try and bring in various border disputes with regard to regional temperature trends.
In this case simply going to the NSIDC website provides an appropriate explanation.
“except that treelines are not relevant to sea ice”
“Arctic researchers” covers more than “Arctic sea ice researchers”
“the Sea of Okhotsk is not the Arctic Ocean. Rationalization won’t make it so. “
It’s pretty clear that for Arctic research it is.
Deciding to change the defining of the Arctic to exclude the parts of it that are melting after they start melting is the rationalizing that’s going on here. You can redraw the maps all you like but the ice will still be melting.
REPLY: It is nebulous, I just had Walt Meir agree with that statement in an email, plus also say that “NSIDC’s boundaries are also somewhat arbitrary”. I’m curious to find out what the 30 year trend is inside the Arctic circle, and you aren’t the least bit curious? The Arctic circle is based on physical properties of Earth’s orbit, inclination, and solar illumination. The boundaries we see at NSIDC look like gerrymandered politcal districts.
I find your lack of curiosity and your insistence that the Sea of Okhotsk is in fact part of the Arctic to speak volumes. Your mind is closed to what if questions, as are many AGW proponents – Anthony

Gneiss

Latitude writes,
“….Winter max and summer min are always weather
May and Dec it all comes back together”
It’s true that weather, winds and such, play a notable role in determining the exact summer minimum. But May is actually the *least* predictable month, and December the most predictable, in terms of their downwards trends.

MrCannuckistan

Didn’t I read something last year about a 5 day averaging of NSIDC data? Maybe that explains the discrepancy.
MrC

stevo

Oh wow, that’s a good one! When faced with the facts of ongoing northern hemisphere sea ice decline, I did not expect that people would start quibbling over the definition of Arctic. That is a new level of pettiness and irrelevance. Nebulous indeed. Ha!
REPLY: Well Dr. Walt Meier of NSIDC didn’t think it was “petty and irrelevant”, and has agreed to provide a plot for me in a couple of weeks. The question really stems from my curiosity about the orange boundary lines on the NSIDC extent map, which look much like gerrymandered political districts. Even Walt agrees that the boundary definitions are “somewhat arbitrary” – Anthony

Gneiss

Mike writes,
“I am not sure, but I think some of the melting is from warmer ocean water below.”
Yes, melting from below is a major force and will become more so. People who focus exclusively on air temperatures have read none of the research.

Andrew30

Gneiss says: March 24, 2011 at 4:57 pm
“Yes, melting from below is a major force and will become more so. ”
Actually, in a week or so “You’ll wonder where the yellow went!”
http://weather.unisys.com/surface/sst_anom.gif
Cooling, for a while now, all oceans, not just the equtoral eastern pacific.
As for the air….
Monthly deviation from 30 year global average temperature (Measured by the AMSU flying on the NOAA-15 satellite)
Year Month Degrees C
2010 Jan +0.54
2010 Feb +0.51
2010 Mar +0.55
2010 Apr +0.40
2010 May +0.45
2010 Jun +0.39
2010 Jul +0.42
2010 Aug +0.44
2010 Sep +0.48
2010 Oct +0.31
2010 Nov +0.27
2010 Dev +0.18
2011 Jan -0.01
2011 Feb -0.02
Again, cooling, expect this month to be -0.25

gaya hap

Latitude says:
March 24, 2011 at 12:35 pm
“Start your record keeping at a time when predictions were that we were going into another ice age and glaciers would soon cover us all….”
Whose predictions? Time and Newsweek?

HB

I find it fascinating following this year’s trend in arctic ice and the La Nina effect appearing to be pushing all that warm ocean up towards the arctic. I wonder if Bob Tisdale has any thoughts on this?

Gneiss

Anthony writes,
“The question really stems from my curiosity about the orange boundary lines on the NSIDC extent map, which look much like gerrymandered political districts. Even Walt agrees that the boundary definitions are “somewhat arbitrary””
Any particular definition of where the Arctic ends is bound to be somewhat arbitrary. But the orange lines in NSIDC extent plots are not boundary lines. They mark the median ice extent for that particular date, over 1979-2000. The move as the date changes.

martin brumby

There are always lots of hyperthermalist trolls who show up every time Arctic ice gets a mention.
Perhaps one of them could enlighten me as to why I should care what the ice extent is?
Interested, OK.
Bothered? I don’t think so.

gaya hap

” And clearly, the Sea of Okhotsk is not part of the Arctic Ocean, yet NSIDC tracks “Arctic sea ice” there. Take these non-Arctic areas out, and let’s see how the true Arctic has fared over the last 30 years. – Anthony
Anthony. The “Arctic Ocean” is not the same as the “Arctic Ice Cap”.
The Arctic Ocean is not going to arbitrarily constrain the extent of circumpolar ice, regardless of what name that sea ice is called. The colder it is, the greater its extent is going to be beyond the technically defined “Arctic Ocean”. The warmer it gets, the more the “ice cap” will shrink from its former boundaries beyond and within the Arctic Ocean.
The fact that circumpolar ice pack has been shrinking is due to forces that are not going to be constrained by man made boundaries and definitions. For example, if there’s a rising level of flooding water slowly risng to the level of my house, I am not going to say that my house in not in danger from that flood simply because “It hasn’t reached my doorstep yet.”
For reasons of simple semantics, it’s going to be referred to as “Arctic sea ice” simply because the Arctic ocean is where most, not all, of the circumpolar ice pack is. There is no reason whatsoever to tag the names of a couple of other non Arctic regions to the phrase “Arctic sea ice” since that would create a cumbersome composite phrase.

Mike

Of course the real issue is why is the Arctic region losing ice. Is it mostly from warmer than normal ocean water that was warmed elsewhere because of AGW? Or is the water warmer because of local AGW during the summer? I have read that part of the cause is an increase in black carbon, aka soot, from industrial sites in Russia and Asia. This is human caused but is distinct from GHG warming. And there may well be natural cycles in ocean circulation or wind patterns that are playing some role. Are there good review articles, readable by non-specialists, that quantify these or other factors?
Related issues are concerns about permafrost loss and methyl hydrates.

Werner Brozek

“George E. Smith says:
March 24, 2011 at 3:12 pm
Well, the temperature in the Arctic is about 21 K below freezing.
Are you sure you don’t mean -21 deg C ?”
What is the difference? Suppose the temperature is 98 deg C or 371 K. Would I not be equally correct to say this is either 2 K below boiling or 2 deg C below boiling?
As for the other point about what constitutes the Arctic. Whatever your definition is, I would think it would only affect certain months of the year, for example July to November. During November to July on the other hand, isn’t all of the water above the Arctic circle frozen anyway? So if the Arctic is defined as being far enough north, then there would be 100% ice coverage every February. Or am I wrong?

Mike

@martin brumby
The loss of ice decreases Earth albedo. Even without AGW if something, natural or human, caused a loss of sea ice cover that would cause global warming. The related loss of Greenland ice is causing sea level rice. There are also national security issues:
Climate Change Poses Arctic Challenge for U.S. Navy |
The U.S. National Academy of Sciences exposes new national security challenges for the Navy as a result of climate change

So, whatever the cause is, yes you should be concerned. (Note: I did not say alarmed, I said concerned.)

gaya hap

martin brumby says:
March 24, 2011 at 6:18 pm
“There are always lots of hyperthermalist trolls who show up every time Arctic ice gets a mention.
Perhaps one of them could enlighten me as to why I should care what the ice extent is?”

*****************************************************
Ad Hominems are a sign of weakness. First, a Troll is a person who tries to create trouble. Perhaps, by your definition, a simple response based on facts, is troubling. Perhaps the mere presence of someone who says something that is not liked is considered “trolling”?
“Hypethermalist” is simply a silly phrase. The board rules prevent namecallingand that should not be limited to the examples given or to one side alone
As for the answer to the question of why someone should care about the sea ice extent, that is common knowledge. The very short answer is:
The more open ocean is exposed, the more it changes the weather in surrounding regions. This is due to the differences between open water and sea ice in absorbing and releasing heat; evaporation; and itensification of storms through an increase in ocean heat release.
Those changes, namely increased rainfall/snowfall have already damaged crops in Canada. Australia and Pakistan while not effected by the Arctic ice cap shrinkage, have been flooded due to an increase of heat in the oceans.
Expect this alteration in weather patterns to continue and worsen throughout this decade and beyond. And so will its effects and repercussions such as crop loss, escalating food prices, and eventually social unrest.
So the basic answer to your question, “. . . why I should care what the ice extent is?” is:
“Because you like to eat.”

Glad to see others are curious about the difference in “Arctic” ice. I too noticed that according to the NSIDC orange line, most of the difference in ice area was at lattitudes that no one would consider Arctic. In fact, the bulk of the differnce was at a lattitude similar to Calgary, Alberta which no Canadian considers to be “north” at all!
Why must a simple question born of curiosity be considered so political by some?
I share your curiosity Anthony and I’m interested in Walt’s thoughts.

R. Gates

Everyone knows sea ice is my favorite topic as I feel it is the ultimate test of the validity of AGW theory. It’s a bit early to be predicting summer minimums perhaps, as we’ll have to see how quickly the ice retreats in the keys areas of the Beaufort and Barents Sea. Mid-May to Mid-June are critical in these areas in looking at the amount of open water in these areas early on can be a great indicator of the ultimate extent of melting later on in the season.
Right now though, things are shaping up to give 2007’s summer minimum a real test. as the Arctic has seen many warmer than normal areas all winter as the cold air was pushed further south by the early winter negative AO conditions as well as several periods of a Dipole Anomaly that didn’t allow cold air to be trapped in polar regions. We had the study released in February that showed we had the warmest water in 2,000 years flowing into the Arctic over the past few decades.
http://www.montrealgazette.com/technology/Water+entering+Arctic+warmest+years/4182089/story.html
An interesting melt season awaits…

Mike

In my 6:44 post – still in moderation – I should have said methane hydrates or more correctly methane clathrates, and not methyl hydrates.

EFS_Junior

I know what, I’ll just call it Northern Hemisphere Sea Ice Extent.
Same goes for Southern Hemisphere Sea Ice Extent.
The Arctic Circle is an arbitrary definition with respect to the overall sea ice extent in the Northern Hemisphere.
I’m sure I’d be interested in what precentage of sea ice exists above (or below) any given latitude at any given time.
However, a capricious definition, that goes to 100% is meaningless, as we should all know that there are not definitive boundaries for the Arctic Ocean (e. g. it is not an inland body of saltwater, per se), when speaking of sea ice extent during the Northern Hemisphere summertime and/or wintertime and/or anytime.
So, for example, my definition of sea ice extent is all areas above 89N. Therefore, I could state, correctly, that the current record shows that area always occupied by > 15% sea ice extent, or it’s value is always 100% occupied by > 15% sea ice extent.
Thus, a capriciously defined flatline, of any duration, actually tells me nothing about what all is going on, outside of that arbitrary definition, in the entire Northern Hemisphere with respect to total sea ice extent/area/volume.
You either include all areas of interest, e. g. the Northern Hemisphere itself or the Southern Hemisphere itself (with their respective seasonal cycles), with the knowledge that these respective areas are driven by entirely different boundary conditions/processes, or you create capricious definitions to suit your own baises, I’d always choose the former.
Now, if you want to talk about total amount of frozen water on the Earth, or in each hemisphere, that is a different matter then what all is being discussed above (seasonal variation of Northern Hemispheric sea ice extent/area/volume).

R. de Haan

That’s all what’s left. A few orange lines on a map to underline a religion.
Even the Baltic gets a quick mark.
Yes, we’re short of ice in the Baltic all right.
Must be caused by the nuke that came to the rescue:
http://eureferendum.blogspot.com/2011/03/nuke-to-rescue.html
And there is the Catlin Team who are forced to swim the entire route.
http://stevengoddard.wordpress.com/2011/03/24/catlin-team-faces-42c-and-five-metre-thick-ice/
They should have watched the orange lines.

Werner Brozek says:
March 24, 2011 at 6:47 pm

What is the difference? Suppose the temperature is 98 deg C or 371 K. Would I not be equally correct to say this is either 2 K below boiling or 2 deg C below boiling?

I always understood that kelvin was an absolute scale, rather than a relative one like degrees Celsius. If that were the case, your terminology would not be right, and C would be a better usage (with the degree symbol had there been one in a keyboard).
Further reading on the iterwebs tells me this is not the case, despite what I had learnt, so you are right. It still seems wrong to me: 2K is two Celsius above absolute zero in my head. Still, the older I get, the more used to being wrong I get!

geo

I’m not liking what I’m seeing so far. I think there’s a chance we go below the 2007 minimum, and I don’t see much chance we exceed the 2010 minimum. Wind and tide will play their as yet unpredictable role, of course.
Having said that, I don’t see any reason to think that Mr. Wilson, who predicted a 1M summer extent minimum last year for ARCUS yearly summer prediction roundup will be in the ballpark this year either. . . and Mark Serreze still won’t find his autumnal equinox stocking stuffed with his hoped-for “ice free north pole” this year either (for the 4th year in a row).

gaya hap says:
March 24, 2011 at 7:01 pm
Oh, I love this game…..

As for the answer to the question of why someone should care about the sea ice extent, that is common knowledge. The very short answer is:
The more open ocean is exposed, the more it changes the weather in surrounding regions. This is due to the differences between open water and sea ice in absorbing and releasing heat; evaporation; and itensification of storms through an increase in ocean heat release.

Nope, sorry. It is still not at all clear what effect the loss of ice has. It certainly had very little or no measurable effect on any climate when it was very low early last century, and in the middle of last century.
[handy hint: it has happened before, no disasters were caused, we can relax, now]

Those changes, namely increased rainfall/snowfall have already damaged crops in Canada. Australia and Pakistan while not effected by the Arctic ice cap shrinkage, have been flooded due to an increase of heat in the oceans.

Nope again. Our floods had less than zero influence from the ice in the Arctic. To suggest they did is extremely strange. They were caused, as they always are, by La Nina.
[handy hint: it has happened before, happens every ten years or so, and there is nothing we can do about it except prepare for it, and not build on flood plains just because there have been no floods for nine years!]
Canada I have no idea about. I guess it’s nearer, but still cannot see your chain of causation, at least if you use real empirical evidence instead of following cant.

Expect this alteration in weather patterns to continue and worsen throughout this decade and beyond. And so will its effects and repercussions such as crop loss, escalating food prices, and eventually social unrest.

Nope once gain. Increased CO2 has been proved to be beneficial to plants in all conditions., Increased temperature periods in history are the times when we had much better conditions. Cold kills. Warmth nurtures. Look at the statistics for deaths, even as near the equator as India. Cold kills, much, much more than warmth.
Any speculation that the melting of any ice at all will severely affect our climate is just that, speculation. There is a significant possibility that this will help the oceans to cool anyway (not being insulated), and this is a strongly negative feedback. That is why the MWP did not send us into all of the hyped up tipping points that scaremongers have invented. They do not exist except in alarmists imaginations.

Oh, yes, I forgot. Those escalating food prices leading to social unrest? They were caused by misguided greenies who thought using food crops to power our cars would be a more sensible thing than eating them.
They really deserve the title ‘ecotards’ I’m afraid.