NSIDC: Arctic Sea Ice Melt Season – latest start on record

From NSIDC Sea Ice News:

Cold snap causes late-season growth spurt

Arctic sea ice reached its maximum extent for the year on March 31 at 15.25 million square kilometers (5.89 million square miles). This was the latest date for the maximum Arctic sea ice extent since the start of the satellite record in 1979.

Early in March, Arctic sea ice appeared to reach a maximum extent. However, after a short decline, the ice continued to grow. By the end of March, total extent approached 1979 to 2000 average levels for this time of year. The late-season growth was driven mainly by cold weather and winds from the north over the Bering and Barents Seas. Meanwhile, temperatures over the central Arctic Ocean remained above normal and the winter ice cover remained young and thin compared to earlier years.

map from space showing sea ice extent, continents

Figure 1. Arctic sea ice extent for March 2010 was 15.10 million square kilometers (5.83 million square miles). The magenta line shows the 1979 to 2000 median extent for that month. 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

Arctic sea ice extent averaged for March 2010 was 15.10 million square kilometers (5.83 million square miles). This was 650,000 square kilometers (250,000 square miles) below the 1979 to 2000 average for March, but 670,000 square kilometers (260,000 square miles) above the record low for the month, which occurred in March 2006.

Ice extent was above normal in the Bering Sea and Baltic Sea, but remained below normal over much of the Atlantic sector of the Arctic, including the Baffin Bay, and the Canadian Maritime Provinces seaboard. Extent in other regions was near average.

graph with months on x axis and extent on y axis

Figure 2. The graph above shows daily sea ice extent as of April 4, 2010. The solid light blue line indicates 2010; green shows 2007; dark blue indicates 1999, the year with the previous latest maximum extent, which occurred on March 29, 1999; and solid gray indicates average extent from 1979 to 2000. 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

Sea ice reached its maximum extent for the year on March 31, the latest maximum date in the satellite record. The previous latest date was on March 29, 1999. The maximum extent was 15.25 million square kilometers (5.89 million square miles). This was 670,000 square kilometers (260,000 square miles) above the record low maximum extent, which occurred in 2006.

Sea ice extent seemed to reach a maximum during the early part of the month, but after a brief decline, ice extent increased slowly and steadily through the end of the month. By the end of the month, extent had approached the 1979 to 2000 average. During March 2010, ice extent grew at an average of 13,200 square kilometers (5100 square miles) per day. Usually there is a net loss of ice through the month.

average monthly data from 1979-2009

Figure 3. Monthly March ice extent for 1979 to 2010 shows a decline of 2.6% per decade.

—Credit: National Snow and Ice Data Center

High-resolution image

March 2010 compared to past yearsThe average ice extent for March 2010 was 670,000 square kilometers (260,000 square miles) higher than the record low for March, observed in 2006. The linear rate of decline for March over the 1978 to 2010 period is 2.6% per decade.

figure 4: air pressure map

Figure 4. The map of sea level pressure (in millibars) for March 2010 shows high pressure over the central Arctic (areas in yellow and orange) and areas of low pressure over the Bering and Barents seas (areas in blue and purple). The low pressure systems over the Bering and Barents seas have helped to push the ice edge southward.

—Credit: National Snow and Ice Data Center courtesy NOAA/ESRL Physical Sciences Division

High-resolution image

Late-season growth spurt

The maximum Arctic sea ice extent may occur as early as mid-February to as late as the last week of March. As sea ice extent approaches the seasonal maximum, extent can vary quite a bit from day to day because the thin, new ice at the edge of the pack is sensitive to local wind and temperature patterns. This March, low atmospheric pressure systems persisted over the Gulf of Alaska and north of Scandinavia. These pressure patterns led to unusually cold conditions and persistent northerly winds in the Bering and Barents Seas, which pushed the ice edge southward in these two regions.

figure 5: air temperature map

Figure 5. This map of air temperature anomalies for March 2010, at the 925 millibar level (roughly 1,000 meters or 3,000 feet above the surface), shows warmer than usual temperatures over most of the Arctic Ocean, but colder than usual temperatures in the Bering and Barents seas, where sea ice extent is above normal. Areas in orange and red correspond to positive (warm) anomalies. Areas in blue and purple correspond to negative (cool) anomalies.

—Credit: National Snow and Ice Data Center courtesy NOAA/ESRL Physical Sciences Division

High-resolution image

Meanwhile, elsewhere in the Arctic

This winter’s strong negative mode of the Arctic Oscillation was moderated through the month of March. Average air temperatures for the month nevertheless remained above average over the Arctic Ocean region. Overall for the winter, temperatures over most of the Arctic were above average, while northern Europe and Siberia were colder than usual.

figure 6: ice age image

Figure 6. These images show the change in ice age from fall 2009 to spring 2010. The negative Arctic Oscillation this winter slowed the export of older ice out of the Arctic. As a result, the percentage of ice older than two years was greater at the end of March 2010 than over the past few years.

—Credit: National Snow and Ice Data Center courtesy J. Maslanik and C. Fowler, CU Boulder

High-resolution image

Ice age and thickness

The late date of the maximum extent, though of special interest this year, is unlikely to have an impact on summer ice extent. The ice that formed late in the season is thin, and will melt quickly when temperatures rise.

Scientists often use ice age data as a way to infer ice thickness—one of the most important factors influencing end-of-summer ice extent. Although the Arctic has much less thick, multiyear ice than it did during the 1980s and 1990s, this winter has seen some replenishment: the Arctic lost less ice the past two summers compared to 2007, and the strong negative Arctic Oscillation this winter prevented as much ice from moving out of the Arctic. The larger amount of multiyear ice could help more ice to survive the summer melt season. However, this replenishment consists primarily of younger, two- to three-year-old multiyear ice; the oldest, and thickest multiyear ice has continued to decline. Although thickness plays an important role in ice melt, summer ice conditions will also depend strongly on weather patterns through the melt season.

At the moment there are no Arctic-wide satellite measurements of ice thickness, because of the end of the NASA Ice, Cloud, and Land Elevation Satellite (ICESat) mission last October. NASA has mounted an airborne sensor campaign called IceBridge to fill this observational gap.

More Information

For more information, including animations and satellite images, visit the NASA Arctic 2010 Sea Ice Maximum Web page.

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April 7, 2010 12:21 am

…clearly, the Arctic is in the throes of its death spiral!
Thanks, Anthony! It was a long fall & winter, checking the NSIDC site every day…glad this worked out!

Leon Brozyna
April 7, 2010 12:46 am

I see they managed to stay on message with tales of gloom and doom despite the improved showing of extent. This one line is a prime example of the art of creative spin:

The average ice extent for March 2010 was 670,000 square kilometers (260,000 square miles) higher than the record low for March, observed in 2006.

They don’t say so in as many words, but through the careful choice of words manage to suggest that this year’s low extent for March was only exceeded by the extent recorded in 20006. Yet a quick look at the years on display at the IARC-JAXA site reveal that this years extent was only significantly exceeded in 2003, while this year exceeded all years since. A rather different tale than that conveyed in their carefully crafted spin.
We’ll see how the ice does through the year. Personally, I’m looking for a showing close to the 6 m km² mark.

April 7, 2010 1:00 am

To Mr Watts and Contributing Authors,
Probably I am not the first commenter rising the question of the maps with the misleading colors used in nearly every climate issue presented here on WUWT weblog.
Why do use ***only*** anomaly maps without absolute counterparts?
For example. Fig.5 shows ***warm*** over the Arctic but if the average temperature over the area in the presented time period were -10 deg then the whole region would be in the grip of small but ***still*** freezing temperatures. Casual look at such absolute map would give me and others more than the true picture of the ice-melting-or-not issue.
Use the PsyOps techniques 🙂 (or popular science approach) to show WUWT readers that we are ***realists*** as far as the “climate change” issue is concerned.
Thank you.
Best regards
Przemysław Pawełczyk
REPLY: This entire post was the NSIDC Sea Ice News, reposted here. Complain to them about the visuals.

sensorman
April 7, 2010 1:01 am

“As a result, the percentage of ice older than two years was greater at the end of March 2010 than over the past few years.”
Is it just me, or does the lower plot in Fig 6 not contradict this statement?
Looks like the boundary of the green area (>2 years old) ends up lower than every other year except 2009.

April 7, 2010 1:13 am

Mr Moderator,
You irked me a lot. I was not writing about this one post but the prevailing attitude.
I wasn’t complaining – I was suggesting. My remarks were not to stick a thorn in your… back but to make the blog better. Decidedly for me, I can speak only for myself.
Regards
Reply: I believe Anthony responded to you. ~ ctm

R.S.Brown
April 7, 2010 1:26 am

And here’s the Northern Hemispheric ice coverage map as of
6 April from Environment Canada in black and white:
http://www.weatheroffice.gc.ca/data/analysis/350_50.gif

April 7, 2010 1:31 am

Leon Brozyna, it’s a question of mindset: is your tumbler of, let’s say… whisky on the rocks, half full or half empty?
And as we well know: ‘The spin doctors of climatology
Deny any bias in their sea ice methodology.’

R. de Haan
April 7, 2010 1:39 am
R. de Haan
April 7, 2010 1:46 am
R. de Haan
April 7, 2010 1:54 am
Capn Jack.
April 7, 2010 2:17 am

[snip, as you guessed. ~ ctm] Mr Unpronouncable. Check the source.
I know snip.
That line mathematically is linear not a seasonal or a parabolic as a sinusoidal would be, in a fluctuating series.
That curve actually is what one calls abnormal for a sinusoidal.
The words are talk.

Capn Jack.
April 7, 2010 2:26 am

Fluctuating 3 d series.

Capn Jack.
April 7, 2010 2:27 am

The map may be 2 D but the event is 3 D.

yamaka
April 7, 2010 2:58 am

Is it just me or do the September 09/March 10 plots in Fig 6 make no sense.
If there was 1-2 year ice or older present in September 2009 at the end of the melt, how can the same area only have ice < 1 yr old in March 2010?
Also how can the area near Alaska be open ocean in September 09 but have 1-2yr and multi yr ice in March 10?
Long time lurker, first time poster – Great site.

Capn Jack.
April 7, 2010 3:13 am

at least.

Joe
April 7, 2010 3:26 am

It would be very interesting to see the salinity levels from year to year.
The temperature was warmer and the Sea Ice grew much greater.
The other anomally is that the pressure systems this winter stayed for very long periods of time. This would be much calmer winds that would allow more Ice growth without winds breaking them up with waves.

Editor
April 7, 2010 3:37 am

NSIDC say “Meanwhile, temperatures over the central Arctic Ocean remained above normal and the winter ice cover remained young and thin compared to earlier years.“.
Obviously it is remarkable that the ice remained young. Can ice get years older in a few months?
They appear to answer this question later on: “this winter has seen some replenishment …] However, this replenishment consists primarily of younger, two- to three-year-old multiyear ice; the oldest, and thickest multiyear ice has continued to decline.“.
That looks to me like a “yes”.

Rhys Jaggar
April 7, 2010 3:38 am

The AMRE plot shows sea-ice extent now greater than all years back to 2002.
Is there older data to say when the last year was that ice extent was greater??
Can someone explain to me why NSIDC say the ice age/quality is still poor, when this site was showing lots of diagrams showing ice quality far superior to recent times?
Request for enlightenment, not a demand for blame….

Larus
April 7, 2010 3:46 am

@ yamaka
Ocean ice in the Arctic floats freely on the surface of the ocean, and it can be pushed around by the winds. Also, please note that the ice you see in NSIDC graphs is not swathes of solid ice – it’s “area of ocean with at least 15% ice.”
@Przemysław Pawełczyk
If you want to establish whether or not a given area is warming over time (which is an important element of the AGW debate) what better way to do it than present current temperatures as deviations from long-term mean (anomalies)?

Capn Jack.
April 7, 2010 3:47 am

Now this I will say that curve part is one of two things.
We have a behavior in a multivariable systems of forces that just went linear or asymptotic at some level, at n dimensional level.
Or we got friggen in the riggen with datasets.
My best guess friggen in the riggen, thats an R1 fit on a sinsusoidal curve.
Yer it’s the butler wot done it playing catch up covering his tracks..

FergalR
April 7, 2010 3:47 am

yamaka (02:58:43) :
That’s older ice which has been dragged clockwise by the Beaufort gyre. That circulation has been stronger than in recent years because of the mainly negative Arctic Oscillation since October – it tends to keep ice and colder water circulating in the Arctic instead of flushing it out into the Atlantic.

Capn Jack.
April 7, 2010 4:00 am

I always wanted to use asomptopical in conversation.
But it’s a word you just dont get to use in polite company.
Not like fraud.

fafhrd
April 7, 2010 4:15 am

I’m with yamaka. The method to determine multi-year ice needs to be looked at if ice didn’t exist in an area in 2009 and is multi-year 6 months later or was multi-year at the end of the melt and becomes new ice at the end of the freeze. I realize that the ice is in motion and what was in one spot may very well have rotated to a new location, but these pictures just make me question the quality control of the thickness estimations.

Editor
April 7, 2010 4:17 am

More ice, same old spin, “Meanwhile, temperatures over the central Arctic Ocean remained above normal and the winter ice cover remained young and thin compared to earlier years.”
The Arctic Ocean could remain completely frozen year around and NSIDC would still find signs of sea ice decline…

April 7, 2010 4:22 am

“Cold weather” caused late melt, but “warm climate” caused 2007 low.
Place your bets for summer minimum.

Editor
April 7, 2010 4:26 am

NSIDC: “The negative Arctic Oscillation this winter slowed the export of older ice out of the Arctic. As a result, the percentage of ice older than two years was greater at the end of March 2010 than over the past few years.”
I would have given honorable mention to the recovery in the young ice since a couple years ago and the related recovery in the 1-2 yr old ice last year. I might have even called it remarkable. I wouldn’t have given full credit to the more ephemeral negative AO.
Clearly I’m not cut out to work at the NSIDC. There’s a good chance next year will have a further increase in the 2 year old ice, perhaps I’ll spend the next year looking for some anomaly to excuse further recovery.

Ian B
April 7, 2010 4:48 am

Yamaka
Remember that this is Arctic sea ice, and so is floating. It moves in response to wind and current (which was largely responsible for the extremely low mimimum value in summer 2007).
A couple of interesting points:
1) This winter has been relatively warm in the Arctic, yet has seen more ice accumulation than several other recent years, and with a very late maximum – shows that there are other factors than temperature to consider (wind and current, precipitation, local conditions in different basins)
2) The extent based on both 15% and 30% sea ice is running close to long term average, suggesting that the high extent is not limited to very fragmented and thin ice, but to significant accumulation.
However, there seems to be poor correlation between maxima and minima – the extent at peak melting always seems to be tightly bounded. Perhaps someone with more time and knowledge on this subject could take a look at how the ice margins during rapid melting (and freezing) match with isotherms during these periods.

Editor
April 7, 2010 5:05 am

Przemysław Pawełczyk (01:00:12) :

Probably I am not the first commenter rising the question of the maps with the misleading colors used in nearly every climate issue presented here on WUWT weblog.
Why do use ***only*** anomaly maps without absolute counterparts?

You’re not the first, and not all graphics/maps display anomalies.
Maps with absolute temperatures have their place, but once you figure out there’s a 50K difference between the cold and warm areas in the region shown on the maps above, that all becomes background knowledge and not very interesting in discussing longer term ice cover changes.
One source of maps with absolute temps is http://wxmaps.org/pix/clim.html, but they don’t reach the poles. http://wxmaps.org/pix/hemi.fcst.html does reach the north pole, but only at 850 mb, and the graphs are very “busy” and tough to read.
Perhaps you could contact the NSIDC and ask that they produce a series of maps of average temperatures for the covered region for each month of the year. Ask for maps that cover the satellite record (those cover the warm PDO phase) and also for the last 10 years (to cover the peak PDO-influenced temperatures).

hunter
April 7, 2010 5:09 am

This of course is weather.

Mike Davis
April 7, 2010 5:19 am

Yamaka:
The wind driven ice changes the location and area covered even during ice growth seasons. Wind driven compaction will give the appearance of ice loss. OTOH the wind can also spread the ice to cover more area. These figures represent locations with more than either 15% or 30% depending on who is guessing the amount of ice. Claims of either greater or lesser in recorded history are equal to exaggeration /bias. I will say thank you for this example of the spin NSIDC and other government groups put on weather issues to justify their existence. One day they will learn there is only so far over the reality line they can cross before they make their positions valueless.

Henry chance
April 7, 2010 5:22 am

How are we coming on tourist boat rides in the Northwest passage?
Did they refund the tickets?

Stephan
April 7, 2010 5:23 am

Oh noo dios mio que pasa?
http://ocean.dmi.dk/arctic/icecover.uk.php

Jack Bailey
April 7, 2010 5:56 am

Where is the discussion on reflectivity with a larger sea ice area no matter what the thickness?

Bruce Cobb
April 7, 2010 5:56 am

It’s shocking and sad to see Serreze gradually go from scientist in 1992 and finding “no evidence of global warming” to manmade warming True Believer in 2009 and his statement “you are probably looking at ice-free summers by 2030. I’d call that a death spiral”.
By 2030 the whole manmade global warming/climate change hysteria will be a distant memory of a nightmarish time in human history, when reason, rationality, and science were thrown out the window, and those attempting to restore them were reviled, disparaged, and threatened. Mankind will be seen to have gone slightly mad, and children will study it in history books and marvel at the level of stupidity, avarice, and self-aggrandizement of so-called “climate scientists”, and the despicable actions of NGOs, politicians, the MSM, and assorted carpetbaggers seeking to capitalize from it.

OceanTwo
April 7, 2010 5:57 am

I don’t have problems with anomaly maps, even if they do ‘look bad’. But this last point is the issue – they *look* bad.
From that standpoint, they are abused: they are presented to the layman (a person who has no background knowledge) and the extreme elements are highlighted, in text and pictures, and disingenuously ‘correlated’ to unrelated occurrences.
The problem isn’t with the anomaly mapping/charting but with the education and understanding of the average person to whom the information is being presented to.
I believe, today, we are less educated than we were in the past. This is a world-wide phenomenon (of course, I’m committing the sin of extrapolation from what I observe in both the US and the UK).
There is an expanding gray area where facts, theories, causality, politics and ideology are intermixed and interchanged – the uninitiated and undereducated cannot distinguish these effects for what they really are.

terry46
April 7, 2010 6:00 am

From what all the global warming crowd was telling us I thought all the ice was supposed to be gone by now. If it is so warm why has the ice grown?

starzmom
April 7, 2010 6:03 am

About the claim that Arctic temperatures are above normal–how many temperature sensors do they have and how far apart are they? How much extrapolation goes into that statement? It comes from NOAA. Is it related to the temperature map that appears to be based on a handful of data points extrapolated across thousands of square kilometers? Just asking.

kadaka
April 7, 2010 6:03 am

At the moment there are no Arctic-wide satellite measurements of ice thickness, because of the end of the NASA Ice, Cloud, and Land Elevation Satellite (ICESat) mission last October.
Thus they are admitting their guessing is worse than before?
…and the winter ice cover remained young and thin compared to earlier years.
So the ice has gone from rotten to raw.
Thus the Arctic is healing up, but it really should put on a bandage over the bad spot.

terry46
April 7, 2010 6:18 am

Thanks, Stephan (05:23:03), for showing us the present ice extent. Now will this make the cable news? Maybe on Fox but definitely not on MSNBC nor CNN. Do you suppose we need to contact NSIDC to let them know of the sea ice extent? They probably already know this, so how they will spin this one? I KNOW, I KNOW, GLOBAL WARMING.

HereticFringe
April 7, 2010 6:18 am

Note that their March average includes a lot bigger difference between the statistical average and the current average than the April data is likely to show, in which case their report in May should show a big uptick.

Alberta Slim
April 7, 2010 6:21 am

Stephan (05:23:03) :
“Oh noo dios mio que pasa?
http://ocean.dmi.dk/arctic/icecover.uk.php
The chart Stephan refers to, looks a lot clearer.
It also explains the info.
Przemysław Pawełczyk take a look.

April 7, 2010 6:24 am

I must say I was pleasantly surprised with the almost neutral, (with respect to AGW,) tone of the report. May this trend continue into the future.

wws
April 7, 2010 6:30 am

I loved the part where they said “However, this replenishment consists primarily of younger, two- to three-year-old multiyear ice; the oldest, and thickest multiyear ice has continued to decline.”
Last year the ice was no good because it was made up primarily of that nasty, rotten, 1 – 2 year old ice. Next year they will be lamenting all of that unreliable 3 – 4 year old ice. I wonder how long they think they can keep milking this?

April 7, 2010 6:32 am

Ok, I have a really stupid question – but it’s bugging me so I got to ask.
That last image compares ice from September 2009 – when ice extent starts growing – with ice in April 2010 – when the ice extent starts shrinking, right?
How come there is more 2nd and 3rd year ice at the start of the growing season than at the end of it? How was it that much of that 2nd and 3rd year ice managed to disappear at the same time that fresh new ice was appearing?
My best guess would be that winds and currents combined to compress that older ice so making at appear that there was less of it at the end of the season than at the start – but if that were the case then the whole basis for measuring sea ice extent is pointless. Surely we ought to measure the overall mass of ice rather than just how far it extends?

Pamela Gray
April 7, 2010 6:39 am

To infer ice thickness based on age is a mistake. Ask anyone who lives on the shores of the wind blown Great Lakes. Ask anyone who has lost their river side house to an ice jam. Ask anyone who has crossed the bridge at the bottom of Chief Joseph grade during a long cold winter. Ice compaction is the key to thickness and slow melt, along with winds that are either weakly out to Fram Strait, or are blowing INTO Fram Strait. Maybe we should ask our Ice Reporters at NSICD to take a course in floating ice and wind mechanics in a confined bowl. Or better yet, have them rent a house on the edge of one of the windward sides of the Great Lakes during a cold winter. Bet they will not talk about thin one year ice ever after.

John Egan
April 7, 2010 6:46 am

Eye of the Gyre
As I posted at Climate Progress – the Beaufort Gyre is back.
The Beaufort Gyre is a region almost the size of the Gulf of Mexico with a four-year clockwise spiral – speaking of spirals – in which ice remains trapped for long periods. The dramatic loss of sea ice in 2007 was predominantly in the region of the Beaufort Gyre.
http://nsidc.org/images/arcticseaicenews/20100406_Figure6.png
If you look at the multiyear ice map, you can see a significant plume of second year and older ice extending on the southern edge of the Beaufort Gyre all the way to northeast Siberia before wrapping around. Already, multiyear ice makes a 3/4s circle. Given that 2007 was a year of extreme ice loss, it seems that the Beaufort Gyre is well on its way to reestablishing older ice patterns. 2011 may see a complete loop of multiyear ice with ice in the interior relatively protected from summer melt. That could produce a dramatic increase in the Sept 2011 sea ice minimum.
In addition, NSIDC says that the new ice is “thin” –
Yet this map from Canadian Climate shows that first year ice in the Western Arctic is thick.
http://ice-glaces.ec.gc.ca/prods/WIS56SD/20100329180000_WIS56SD_0004895913.gif
One last note, the NSIDC map also shows open water in the Canadian Archipelago. That is a serious error – not only because the waters of the Northwest Passage are, most certainly, frozen in March – but also because significant amounts of multiyear ice are found in the channels among the Queen Elizabeth Islands.

Tain
April 7, 2010 6:47 am

No mention that ice extent has gone up during an El Nino year. If it weren’t for El Nino, how much more ice might there have been?

R. Gates
April 7, 2010 6:53 am

NSIDC’s latest analysis is an accurate accounting of exactly what occured in March 2010. Furthermore, their point about the warm conditions over the central arctic is also exactly right, and there is a large area of ice in this region that will show rapid melt when the full thrust of the melt season hits. I stand by my prediction of a 4.5 million sq. km. minimum sea ice extent for Sept. 2010 (as measured by IJIS/JAXA). Hudson Bay over to Greenland and then up into the central arctic has been very warm during the extreme negative AO of the winter and the ice will melt faster than normal in these regions.

Henry chance
April 7, 2010 7:00 am

So climate has NOT change. We still have more ice in the winter and less ice in the summer.
The passion to insert spin is so obvious for the warmist. It is an itch they can’t get rid of by scratching.

Dave Wendt
April 7, 2010 7:05 am

If the summer minimum in 2009 was larger than in 2008, why does the Sept 09 map show no ice less than one year old?

John Egan
April 7, 2010 7:13 am

Speaking of predictions – 5.75 mil sq km JAXA.
The ice conditions of the Sea of Othotsk and the Gulf of St. Lawrence have little impact on summer melt in the Arctic Basin since neither is directly linked to the core Arctic. Yes, Newfoundland, Labrador, and southern Greenland have had an extremely warm winter – but the powerful Baffin Island Current moves ice and cold water southwards. Thus, any loss of ice in Baffin Bay and any warming water is going to have a limited impact on the Arctic Basin.
The Bering Sea is a different story. The Bering had greater than normal ice this season – plus, the greatest inflows into the Arctic Basin are through the Bering Strait. Not to mention that ice melt and ice movement is generally from the Bering towards Greenland. So, not only is there more ice and more multiyear ice, but it will take longer for the ice melt to move into the Beaufort Sea.
The switch in the Arctic Oscillation also suggests that wind patterns prevalent in recent years – esp. in 2007 – will not be present. Of course, all bets are off if winds are similar to 2007 – since it has now become well recognized that winds, rather than temperatures, were the primary factor in the 2007 melt.

NZ Willy
April 7, 2010 7:23 am

Here in New Zealand we are sort of hostages to the Antarctic ice cycles. During the summer ice melt the Antarctic blows cold air until late summer. The point is that the freezing/melting cycle keeps that air near 0C/32F, which is seen as cold in summer, and warm in winter.
So lots of freezing would stop the air from becoming too cold. The “warm Arctic air” through the past winter could be evidence of lots of ice growth. Just a thought.

Dave Wendt
April 7, 2010 7:24 am

The graph showing ice age back through the eighties seems to be at odds with Rigor and Wallace 2004 which claimed the ice through the eighties was up to 80% multi year ice.
http://iabp.apl.washington.edu/research_seaiceageextent.html

R. de Haan
April 7, 2010 7:26 am

R. Gates (06:53:10) :
NSIDC’s latest analysis is an accurate accounting of exactly what occured in March 2010. Furthermore, their point about the warm conditions over the central arctic is also exactly right, and there is a large area of ice in this region that will show rapid melt when the full thrust of the melt season hits. I stand by my prediction of a 4.5 million sq. km. minimum sea ice extent for Sept. 2010 (as measured by IJIS/JAXA). Hudson Bay over to Greenland and then up into the central arctic has been very warm during the extreme negative AO of the winter and the ice will melt faster than normal in these regions.
Total nonsense.
According to Joseph D’Aleo (and Joe Bastardi http://www.accuweather.com):
“ENSO models see a quick demise to this El Nino. Some have La Nina returning as early as this summer. This means a hot late summer for the central US but a return to cold across Alaska, Canada and the northern US this next winter.
Arctic ice extend will remain normal. Nothing to panic about”.
http://icecap.us/images/uploads/winter12.jpg

April 7, 2010 7:28 am

Pamela Gray (06:39:34) :
To infer ice thickness based on age is a mistake. Ask anyone who lives on the shores of the wind blown Great Lakes. Ask anyone who has lost their river side house to an ice jam. Ask anyone who has crossed the bridge at the bottom of Chief Joseph grade during a long cold winter. Ice compaction is the key to thickness and slow melt, along with winds that are either weakly out to Fram Strait, or are blowing INTO Fram Strait. Maybe we should ask our Ice Reporters at NSICD to take a course in floating ice and wind mechanics in a confined bowl. Or better yet, have them rent a house on the edge of one of the windward sides of the Great Lakes during a cold winter. Bet they will not talk about thin one year ice ever after.

Still steadfastly denying the reality of this spring’s ice drift Pamela?
The wind is indeed the key to ice thickness and build-up, however it’s not going the way you want it to!
http://i302.photobucket.com/albums/nn107/Sprintstar400/20100325-20100331.jpg
Of course the ice is being stretched by this flow rather than compacted so the ice is very fragmented with leads opening up all over the place. The subs could surface anywhere they want this year.
Look here off the Canadian archipelago where the thickest ice is found, leads everywhere:
http://rapidfire.sci.gsfc.nasa.gov/realtime/single.php?2010095/crefl1_143.A2010095204500-2010095205000.1km.jpg

April 7, 2010 7:43 am

John Egan (07:13:48) :
Speaking of predictions – 5.75 mil sq km JAXA.
The ice conditions of the Sea of Othotsk and the Gulf of St. Lawrence have little impact on summer melt in the Arctic Basin since neither is directly linked to the core Arctic. Yes, Newfoundland, Labrador, and southern Greenland have had an extremely warm winter – but the powerful Baffin Island Current moves ice and cold water southwards. Thus, any loss of ice in Baffin Bay and any warming water is going to have a limited impact on the Arctic Basin.

Except that, as in 2007, the North water polynya is open very early which provides a route for MY ice loss directly from the Arctic, estimates under these conditions are ~10% of the outflow through the Fram.
http://rapidfire.sci.gsfc.nasa.gov/realtime/single.php?2010095/crefl1_143.A2010095204500-2010095205000.500m.jpg

Steve Goddard
April 7, 2010 7:53 am

This is the first recent year with multi-year ice north of Alaska, which is where the low anomalies have been occurring the past few summers.

Mike Ford
April 7, 2010 7:57 am

Why only 1979-2000 for an average? Why not average all full years, 1979-2009? Is it because the 2000’s will put the median below the current average? If that’s the case, well, we certainly can’t show that. Hide the incline!

Norm Milliard
April 7, 2010 7:58 am

Old Ice, New Ice is so interesting. On average, the most old ice you can have is 33% or so since 67% melts every year.
In terms of global warming, it seems the primary concern is refectivity of the ice and I can’t believe that light knows the difference between old ice and new ice or between thick ice and thin ice.
Without a decided continuous decline in the ice versus time curve, regardless of the age of the ice, it’s hard to get too excited over these short term trends. Our knowledge of the history is too limitied to get excited over three year trends or even 30 year trends?
I fear the politics is more important than the science to many of the goverment agencies, their chance to stamp the future with their own brand.
The need to create new taxes is real and great with our recent and projected government’s spending sprees. We are not simply fighting deceptive science; there is a bigger purpose here. There is an attempt to realign our national form, this requires control and cash to support it.

Henry chance
April 7, 2010 8:21 am

Joe Bastardi and some climate “scientist” were on Colbert last night. The pretend scientist didn’t know the arctic ice had been expanding.
Do the pretend scientists actually conduct observations or do they just take bulletins from the IPCC?
http://www.colbertnation.com/the-colbert-report-videos/269929/april-06-2010/science-catfight—joe-bastardi-vs–brenda-ekwurzel

April 7, 2010 8:32 am

I know of quite a few people in the NH who complained about the arctic winters they had the past few years. But aren’t we all happy that the ice is coming back?
it was worth the suffering in the cold!!!….or do we rather prefer global warming?

maelstrom
April 7, 2010 8:39 am

Interesting. Looks like an increase in Gulf of Bothnia and Commander Islands/Aleutians, but decrease off northern East Greenland.

MattN
April 7, 2010 8:40 am

….it’s just weather, nothing more….right?

Stephan
April 7, 2010 9:10 am
The ghost of Big Jim Cooley
April 7, 2010 9:22 am

It ain’t over yet – there’s a tiny uptick on that red line.

Nonegatives
April 7, 2010 9:22 am

..winter ice cover remained young and thin compared to earlier years.
Unlike most of us who wish to return to those earlier years of being young and thin!
Ponce de Leon missed his mark, the Fountain of Youth is in the arctic!

D. King
April 7, 2010 9:30 am

wws (06:30:19) :
I wonder how long they think they can keep milking this?
Just until the carbon markets (Cap and Trade) fully spin up.
But you’re right, this tap dance is looking labored.

kadaka
April 7, 2010 9:36 am

News alert: New hurricane forecast from Colorado State University by Philip J. Klotzbach and William M. Gray.
Reuters’ report with mention of the AccuWeather forecast as well.
Last year was below average, this year is forecast above average… I take it that it’s a safer bet to pick the other extreme rather than a repeat of the same extreme?

Urederra
April 7, 2010 9:46 am

I don’t understand figure 3.
It seems that the average monthly Arctic Sea extent was higher in March 2008 and March 2009 than in March 2010… Or am I missing something?

Grumpy Old man
April 7, 2010 9:51 am

In focusing on Artic ice, the skeptics (or flat earthers of which I am one) are putting too much meaning on one signal. How Artic ice expands and retreats is no doubt connected to global climate but over a period of just a few years, it is more pertinent to look at winds and currents. Of course it easy to laugh at the warmists with their ridiculous predictions of an ice free Artic but if warming continues, it may yet come about. The Earth has warmed since the Little Ice Age and may yet continue to do so. The real question is can we do anything about it? The answer I feel is no. The theory of CO2 warming just doesn’t add up ( see the Roman warming period and the Middle Ages warming period).
Sure, lots of folks want us to believe in CO2 warming and they are sure to makes lots of money out of it with Carbon trading scams but climate will do what it is driven to do – most probaly by the variability of the Sun. We should be looking at a whole host of signals from ocean salinity to glacier melt to have some idea of where our climate is going. Probaly the biggest factor is cloud cover and we don’t even understand this process as yet, although we have pointers.
Given the history of climate, it seems certain that we will face another ice age. Is it in 20 years, 200 years or even 2000 years? Whenever, we certainly know how to survive the next ice age or be able to get off this planet.
I have followed this blog for a few years now and it has always been instructive and thought provoking but please don’t turn it into a point scoring exercise. We need some really serious thought about this. We know that the warmist have a closet mentallity worthy of the most fundamentalist taliban but we must try to see the big picture and not rubbish everything the warnists say but look at it objectively and answer it in a proper critical fashion, ie – scientifically. One signal is not enough.

Urederra
April 7, 2010 10:01 am

Urederra (09:46:56) :
I don’t understand figure 3.

Never mind, I see it now.

Paddy
April 7, 2010 10:26 am

If the average ice extent was the average for the period from 1979 thru 2009, would the current ice extent curve intersect with the average curve? This does seem plausible.

April 7, 2010 10:28 am

Beth Cooper (01:31:07) :
Leon Brozyna, it’s a question of mindset: is your tumbler of, let’s say… whisky on the rocks, half full or half empty?
Then there’s the third option — that the glass is exactly the right size for the drink.

George E. Smith
April 7, 2010 10:34 am

Well one thing that continues to puzzle me, is why they compare recent results with the mean from 1979 to 2000. The JAXA ice graphs only seem to go back to 2003; presumably because that’s when they started observations.
But surely the NSIDC has had enough time to masticate the 2000-2009 data until it fits their agenda, so why not include it in the average.
Seems to me that they cherry picked an anomalous period of high ice; namely 1979-2000, and decided to try and sell everybody that that is what is normal; yet they can’t have had any satellite measurements before 1979; so they have no robust basis for assuming that 1979-2000 was normal, rather than perhaps the most advanced ice growth in a long time.
There’s plenty of historical records, of large areas of ice free arctic oceans from the distant past, so I don’t see the validity of their assumption that 1979-2000 represents long term normal conditions; rather than a cherry picked fluke.

April 7, 2010 10:36 am

I share and support Przemysław Pawełczyk’s observation (01:00:12) about temperature anomaly maps being misleading, and don’t understand the rather rude and unthoughtful attitude toward Mr. Pawełczyk by the moderators.
Those who call Mr. Pawełczyk “Mr. Unpronounceable” should think again. His name is very pronounceable and simple to those who know the rules of the Polish language. Your inability to pronounce it is an evidence of your limited education, nothing else.

Don Penman
April 7, 2010 10:55 am

Having watched the Arctic Ice over the last few years along with many others on this website ,The Arctic ice area and extent remains as unpredictable as ever.I hope that the minimum ice extent is much larger this year ,it would have been last year if the early pattern had continued throughout the summer.I am sure that co2 is not causing the world to warm therefore I am ignoring the “major Parties” in the coming election in the UK and voting for UKIP, when will the UKIP be included in the opinion polls.

April 7, 2010 11:05 am

Norm Milliard (07:58:32),
You are right about old ice vs new ice. You’re right about the rest of it, too.

rbateman
April 7, 2010 11:23 am

Still melting slower than 2003:
03,25,2003,14800781 – 03,25,2010,14282344 – -518437
03,26,2003,14771094 – 03,26,2010,14264688 – -506406
03,27,2003,14755781 – 03,27,2010,14256719 – -499062
03,28,2003,14718594 – 03,28,2010,14299219 – -419375
03,29,2003,14647031 – 03,29,2010,14363438 – -283593
03,30,2003,14533906 – 03,30,2010,14405781 – -128125
03,31,2003,14428281 – 03,31,2010,14407344 – -20937
04,01,2003,14409219 – 04,01,2010,14395000 – -14219
04,02,2003,14335781 – 04,02,2010,14379531 – 43750
04,03,2003,14250469 – 04,03,2010,14328438 – 77969
04,04,2003,14172813 – 04,04,2010,14264219 – 91406
04,05,2003,14129375 – 04,05,2010,14228281 – 98906
04,06,2003,14098750 – 04,06,2010,14207969 – 109219

Richard Sharpe
April 7, 2010 11:24 am

Phil. (07:28:06) said:

Of course the ice is being stretched by this flow rather than compacted so the ice is very fragmented with leads opening up all over the place. The subs could surface anywhere they want this year.

I seem to remember that happening before … not much has changed, eh.

enneagram
April 7, 2010 11:32 am

Ice melting keep as a permanent GWR´s propaganda issue:
http://news.yahoo.com/s/ap/20100407/ap_on_re_us/us_disappearing_glaciers_5
Though:
“Evaporation is accelerated if a wind is blowing, to take the vapor away from the inmediate neighborhood of the snow crystals and to prevent the vapor from condensing on the crystals”
Pauling, Linus, “General Chemistry”

April 7, 2010 11:34 am

Alexander Feht (10:36:44) :
Those who call Mr. Pawełczyk “Mr. Unpronounceable” should think again. His name is very pronounceable and simple to those who know the rules of the Polish language.
There may be some forehead-doinks when they realize they’ve seen the Anglicized version — Polachek.

enneagram
April 7, 2010 11:36 am

Disappearance of high altitude glaciers, where temperatures are always BELOW ZERO, happends during COLD TIMES, when there is no or little water in the atmosphere to keep the balance of NORMAL ice sublimation.
Global warmers have their reasoning INVERTED about the water cycle.

Jimbo
April 7, 2010 11:42 am

R. Gates (06:53:10) :
“….I stand by my prediction of a 4.5 million sq. km. minimum sea ice extent for Sept. 2010 (as measured by IJIS/JAXA).”
I commend you for at least having the guts to make a prediction that can be confirmed or falsified within your lifetime / working life. By the way what would you say if we see further recovery, ie a greater sea ice extent than September, 2009?

NZ Willy
April 7, 2010 11:57 am

R. Gates (06:53:10) : “NSIDC’s … point about the warm conditions over the central arctic is also exactly right, and there is a large area of ice in this region that will show rapid melt when the full thrust of the melt season hits.”
To melt ice, such heat must be applied, that after the ice has melted if you apply that same amount of heat again, the water will be 2/3 of the way to boiling. The point is that NSIDC’s sub-freezing “warm conditions” are totally irrelevant to future melting speed.

Jeff T
April 7, 2010 11:57 am

@ R. de Haan
Please read the update at the end of the “adjustment” article you refer to
http://www.americanthinker.com/2010/04/was_the_arctic_ice_cap_adjuste.html
It shows that there hasn’t been any inappropriate modification of the ice data.

Jimbo
April 7, 2010 12:08 pm

Phil. (07:28:06) said:

“Of course the ice is being stretched by this flow rather than compacted so the ice is very fragmented with leads opening up all over the place. The subs could surface anywhere they want this year.”

Probably right! Here is one sub surfacing wherever it liked including the North Pole!!!
“Skate (SSN-578), surfaced at the North Pole, 17 March 1959.”
http://www.navsource.org/archives/08/tn/0857806.gif
from http://www.navsource.org/archives/08/08578.htm
http://www.icue.com/portal/site/iCue/flatview/?cuecard=41751
See this fascinating study about Arctic sea ice conditions just 6,000 to 7,000 years ago.
http://www.ngu.no/en-gb/Aktuelt/2008/Less-ice-in-the-Arctic-Ocean-6000-7000-years-ago/

AndyW
April 7, 2010 12:23 pm

Grumpy old man said
” How Artic ice expands and retreats is no doubt connected to global climate but over a period of just a few years, it is more pertinent to look at winds and currents. ”
How do wind and currents explain the general reduction over the last 30 years?
http://www.zen141854.zen.co.uk/arctic.jpg
Andy

nandheeswaran jothi
April 7, 2010 12:24 pm

R. de Haan (01:46:09) :
thanks for the timely reminder.

April 7, 2010 12:33 pm

NZ Willy (11:57:35) :
R. Gates (06:53:10) : “NSIDC’s … point about the warm conditions over the central arctic is also exactly right, and there is a large area of ice in this region that will show rapid melt when the full thrust of the melt season hits.”
To melt ice, such heat must be applied, that after the ice has melted if you apply that same amount of heat again, the water will be 2/3 of the way to boiling. The point is that NSIDC’s sub-freezing “warm conditions” are totally irrelevant to future melting speed.

Actually they’re not, the temperature at the ice surface determines the thickness of the ice.
http://nsidc.org/seaice/processes/thermodynamic_growth.html

Terry Ward
April 7, 2010 12:42 pm

AndyW (12:23:18) :
Grumpy old man said
” How Artic ice expands and retreats is no doubt connected to global climate but over a period of just a few years, it is more pertinent to look at winds and currents. ”
How do wind and currents explain the general reduction over the last 30 years?
http://www.zen141854.zen.co.uk/arctic.jpg
Andy”
If they (wind and currents) were the only variables then 30 years of data would not present us even the smallest of clues as to their interactive possibilities, or the tiniest corner of their chaotic palette of chance outcomes.

Dave Wendt
April 7, 2010 12:58 pm

AndyW (12:23:18) :
“How do wind and currents explain the general reduction over the last 30 years?”
This video which accompanies the Rigor and Wallace 2004 paper I linked above {updated to 2007] may help to explain it
http://iabp.apl.washington.edu/animations/Rigor&Wallace2004_AgeOfIce1979to2007.mpg
Here is the commentary that the authors provide
The red dots shows the current location of buoys used to estimate the age of sea ice. The areas of older, thicker ice are shown in white, while younger, thinner sea ice is shown as darker shades of blue.
This animation of the age of sea ice shows:
1.) A large Beaufort Gyre which covers most of the Arctic Ocean during the 1980s, and a transpolar drift stream shifted towards the Eurasian Arctic. Older, thicker sea ice (white ice) covers about 80% of the Arctic Ocean up to 1988. The date is shown in the upper left corner.
2.) With the step to high-AO conditions in 1989, the Beaufort Gyre shrinks and is confined to the corner between Alaska and Canada. The Transpolar Drift Stream now sweeps across most of the Arctic Ocean, carrying most of the older, thicker sea ice out of the Arctic Ocean through Fram Strait (lower right). By 1990, only about 30% of the Arctic Ocean is covered by older thicker sea ice.
3.) During the high-AO years that follow (1991 and on), this younger thinner sea ice is shown to recirculated back to the Alaskan coast where extensive open water has been observed during summer.
The age of sea ice drifting towards the coast explains over 50% of the variance in summer sea ice extent (compared to less than 15% of the variance explained by the seasonal redistribution of sea ice, and advection of heat by summer winds).
The frame jumps are fairly large [2-3 months] so you may want to click through the 87-93 time period frame by frame to really appreciate what they describe.

April 7, 2010 12:59 pm

@Larus (03:46:29) :
@Przemysław Pawełczyk
If you want to establish whether or not a given area is warming over time (which is an important element of the AGW debate) what better way to do it than present current temperatures as deviations from long-term mean (anomalies)?
E.g. +10 deg from the long-term mean +6 deg is not the same as +10 deg over -12 deg mean.
Meanwhile many posts here torments my eyes with red/darkred sheets only and not showing the base or the mean to which I should relate the anomalies.
Examples:
1) Why Joe Bastardi sees red: A look at Sea Ice and GISTEMP and starting choices
http://wattsupwiththat.com/2010/03/23/why-joe-bastardi-see-red-a-look-at-sea-ice-and-gistemp-and-starting-choices/
2) GISScapades
http://wattsupwiththat.com/2010/03/25/gisscapades/
If you are a WUWT frequent reader you probably know how many times keyboard keys were pressed during discussions “how the AGW activist win public support scarring people with from-the-hell colors painting their maps”.
I even allowed myself to joke one time in comments to 1) post about the red colors :
Przemysław Pawełczyk (05:12:20) :
🙂 No, it isn’t. 😉 You (we) should show “normal people” such graphs:
http://www.wetterzentrale.de/pics/Rnhemsnow.html
With all ICE in RED. 😉 The more RED the more ICE. 😉
I have been looking frequently to daily Asia temp maps in the last few month. Nearly all the Asiatic regions was painted in magenta color (~ -35 C deg).
Seeing anomaly maps I know that +10 C deg (BIG RED) anomaly means -25 C deg in reality.
To be exact, this year the Western part of Asia was plotted darkblue on anomaly maps and with orange on the Eastern parts. It doesn’t mean the permafrost was/is now thawing in the Siberian regions closer to Alaska. But how can I be sure?
I know that permafrost didn’t yield CH4 but if you are not a professional and you do not have your brain trained to see the unseen, you left computer screen after reading such article with somewhat dizzy state and ambiguous impressions. I know also that, as polls show, many more people do not believe in AGW theory but are they convinced in 100%? I doubt it.
A lot of people comes here to make their minds against AGW stance. A pinch of popular science relish would do them the right thing – convinced them with their eyes. That’s a psychology matter. That’s why I jested with PsyOps (http://en.wikipedia.org/wiki/Psyop) remark in my former comment.
And last but not least.
Przemysław Pawełczyk should be pronounced Pshemislav Paveltchik. 🙂 It’s rather simple, isn’t it? 🙂
Best regards to all
Przemysław Pawełczyk

Harry Lu
April 7, 2010 1:32 pm

If you check out this plot
http://img682.imageshack.us/img682/3148/deltaseaiceaveragearea.png
which is the linear fit for each day of the year over the AMSRE 2002 to present data.
it shows that the area has been increasing for days up to end of april and then takes a rapid dive to its minimum.
I would expect the same this year – the are will be high (higher than normal) until the begnning of may it will then dive to the minimum (unknown).

NZ Willy
April 7, 2010 1:47 pm

NZ Willy (11:57:35) : “NSIDC’s sub-freezing “warm conditions” are totally irrelevant to future melting speed.”
Phil. (12:33:59) : “Actually they’re not, the temperature at the ice surface determines the thickness of the ice. http://nsidc.org/seaice/processes/thermodynamic_growth.html
Your cite is for ice growth, the issue here is ice melt.

Steve W.
April 7, 2010 2:00 pm

Looking at this: http://ocean.dmi.dk/arctic/icecover.uk.php
You would say the extent trend is flat, and not declining yet! I know we would EXPECT it to be declining now, but is it yet? 🙂 This is great fun to watch.
By the way, something has happened to Arctic ROOS. http://arctic-roos.org/observations/satellite-data/sea-ice/ice-area-and-extent-in-arctic
They are still showing 3/30.

R. de Haan
April 7, 2010 2:01 pm
Henry
April 7, 2010 2:05 pm

What I find curious is that late winter maximum extent is relatively stable year to year (essentially the Arctic Ocean, Hudson Bay, Sea of Okhotsk, Gulf of Bothnia) but the late summer minimum varies much more.
By contrast the late winter DMI polar temperature varies a lot but the late summer temperature is also relatively stable (presumably close to a melting point).
I would assume when there is not a natural constraint then wind and similar effects have much more impact.

April 7, 2010 2:13 pm

Wasn’t it so cold in 1978 they said we were headed for an ice age? Seems unfair to compare (plot) anything from such a cold start? Regardless, it appears things are getting back to normal, (if normal ever left considering the Northwest passage was already open in 1903-1906 when Roald Amundsen sailed it or that the Northeast passage has been open to shipping and commerce since 1934, both long before man-made CO2 contributed to any supposed trend of arctic sea ice melt).
http://wattsupwiththat.com/2009/10/07/the-surprising-real-story-about-this-years-northeast-passage-transit/

jorgekafkazar
April 7, 2010 2:39 pm

Norm Milliard (07:58:32) : “In terms of global warming, it seems the primary concern is ref(l)ectivity of the ice and I can’t believe that light knows the difference between old ice and new ice or between thick ice and thin ice.”
Some weathered ice does show a reduction in albedo, but it’s not directly related to age. Zenith angle is more important than ice or water surface condition.

Anu
April 7, 2010 2:44 pm

Well, that was nice – the early Spring ice almost reached the recent “average” extent line. Brings back memories.
Now, off to the Summer melt:
http://nsidc.org/images/arcticseaicenews/20091005_Figure3.png
Will it be right around the longterm melting trendline ?
http://nsidc.org/images/arcticseaicenews/20091005_Figure2.png
Somewhere between 2007 and 2009 ?
Or is the Death Spiral speeding up the trendline, with another plunge even worse than 2007 in store ? Hard to say – the ice is thinner than this time 2007, the ocean slightly warmer, the global temperature slightly warmer, the sun (with sunspots picking up) slightly brighter – given the right winds and cloudless days, these underlying trends could combine for a massive ice loss.
But it might not be till 2013, or 2015. You can’t rush the slow train wreck of climate change.

Stephen Skinner
April 7, 2010 3:46 pm

Looking at graphs of ice extent whether annually or covering thousands of years, there are no horizontal lines anywhere. Ice is either growing or in retreat, all the time.

George E. Smith
April 7, 2010 4:12 pm

“”” jorgekafkazar (14:39:52) :
Norm Milliard (07:58:32) : “In terms of global warming, it seems the primary concern is ref(l)ectivity of the ice and I can’t believe that light knows the difference between old ice and new ice or between thick ice and thin ice.” “””
Well that could be a risky wager.
The Infra-Red Handbook, has graphs of snow reflectance versus wavelength for various times after first fall; and it is pretty illuminating.
In the near IR from 1.0-2.5 microns, snow reflectandce changes quite rapidly with time. At 1.1 microns where snow reflectance is a maximum, 14 hour old snow has a reflectance of 90%. That drops to 65% after 44 hours, and to 45% after 70 hours.
At 1.3 microns, another local maximum, those numbers are 55%, 40% and 20%.
Even more dramatic at 1.8 microns, giving 20, 15, and 3% respectively.
That is with source and detector each 5 deg off zenith angle (specular reflection), for source and detector at 0deg and 30 deg (diffuse reflection), over that whole o.7 to 2.5 micorn range, fresh snow exhibits typically double the reflectance of 2 day old snow.
The snow density in that time went from 0.137 to 0.216.
Beyond 1.5 microns in the near IR, even fresh snow, never gets above 20% reflectance, and after a couple of days it is well under 5%.
Ice specially on a small scale, and maybe wet, behaves like a refractive solid, and most of the incident radiation is refracted into the solid, and at long wavelenghts absorbed by the high absorption coefficient in the LWIR.
So I’m not impressed by polar ice contributions to earth albedo. The reflectance isn’t high, and the irradiance isn’t either.

rbateman
April 7, 2010 5:31 pm

After taking up the actual measurements of sea ice area and plotting them out, I’m not particulary surprised to see an entirely different story than the ‘infilled hole’ extent.
Disparity exists between the two data sets.
The hole in the satellite coverage has been the playground of imaginations running wild.
Clearly, the Arctic experienced an extended melt season, it wasn’t anything near what it was puffed up to be.

April 7, 2010 7:05 pm

Steve W. (14:00:24) :
By the way, something has happened to Arctic ROOS. http://arctic-roos.org/observations/satellite-data/sea-ice/ice-area-and-extent-in-arctic
They are still showing 3/30.

They had problems with their satellite about a year ago since then they’ve been the odd-man out among the data sets, maybe having more problems?

Anu
April 7, 2010 7:11 pm

George E. Smith (16:12:39) :
So I’m not impressed by polar ice contributions to earth albedo. The reflectance isn’t high, and the irradiance isn’t either.

You might be more impressed when you realize the albedo doesn’t just apply to the infrared. And that after “thin ice’ melts in the summer, we are dealing with open ocean.
http://nsidc.org/seaice/processes/albedo.html
Sea ice has a much higher albedo compared to other earth surfaces, such as the surrounding ocean. A typical ocean albedo is approximately 0.06, while bare sea ice varies from approximately 0.5 to 0.7. This means that the ocean reflects only 6 percent of the incoming solar radiation and absorbs the rest, while sea ice reflects 50 to 70 percent of the incoming energy. The sea ice absorbs less solar energy and keeps the surface cooler.
As they suggest:
You understand the concept of low albedo intuitively when you avoid walking barefoot on blacktop on a hot summer day. Blacktop has a much lower albedo than concrete because the black surface absorbs more energy and reflects very little energy.
In any event, the changing climate has no need to impress anybody.

henry
April 7, 2010 9:37 pm

“…Ice extent was above normal in the Bering Sea and Baltic Sea, but remained below normal over much of the Atlantic sector of the Arctic…”
And this has always been one of the problems – those that gather, process and chart the data get to say what “normal” is.
The chart in fig 2 shows a “normal” for years 1979-2000, and they show traces for only a couple of years outside that range. The trace for 1999, is naturally, within the normal range.
At the end of 2010, will they re-chart to include the latest years? Will they really want to be forced to re-define “normal” as a lower value?
As it is now, they can point to each year after 2000 and call it as below normal. If the “normal” lowers, they’ll lose that edge – the ice will, for a couple of years, fall in the “normal” range. No alarm there, right?

Larus
April 8, 2010 4:16 am

@ terry46 (06:00:16) :
“From what all the global warming crowd was telling us I thought all the ice was supposed to be gone by now. If it is so warm why has the ice grown?”
No Terry, you’re wrong. What the global warming crowd was telling us was that all the ice at the summer minimum might be gone by 2050 at the earliest, possibly well after 2100 (as per IPCC predictions).
What you are looking at now is the winter maximum in 2010.
In short:
1. Summer is not the same thing as winter.
2. A minimum is not the same thing as a maximum.
3. 2010 is not the same thing as 2050.

Gail Combs
April 8, 2010 4:34 am

John Egan (06:46:57) :
Eye of the Gyre
As I posted at Climate Progress – the Beaufort Gyre is back….
…..In addition, NSIDC says that the new ice is “thin” –
Yet this map from Canadian Climate shows that first year ice in the Western Arctic is thick.
http://ice-glaces.ec.gc.ca/prods/WIS56SD/20100329180000_WIS56SD_0004895913.gif
REPLY:
I noticed on the chart are a lot of numbers without labels. can you tell me what the labels are? Location, Feet or Meters or CM of Ice???
Thanks, Great information by the way. Post it to American thinker and elsewhere
http://www.americanthinker.com/2010/04/was_the_arctic_ice_cap_adjuste.html

April 8, 2010 4:47 am

Larus (04:16:05),
Since ice cover is increasing compared with recent years, what’s your fallback position?
click

Gail Combs
April 8, 2010 5:09 am

Alexander Feht (10:36:44) :
“…. don’t understand the rather rude and unthoughtful attitude toward Mr. Pawełczyk by the moderators…”
REPLY:
Anthony was the one who answered the question. His temper is rather short right now because he is having to deal with a Global Warming Stalker.
Given the bad economy and politicians determined to ram economy crippling regulations and taxes down our collective throats, many of us are short tempered these days, especially those who have spent years trying to shove information into closed minds.
I have noticed as Cap and Trade type law becomes more likely to become and after the Health Care bill was passed despite the majority of Americans being opposed to it, tempers around here are much shorter. Yes I know many are not US citizens but if Obama gives the UN sovereignty of the USA it affects everyone. He already is doing so:
at the G20 summit last year in April Obama agreed to sign off on International control over our US financial institutions to the Financial Stability Board. They want control over every detail, not surprisingly right down to setting pay and compensation levels. http://www.investorsinsight.com/blogs/forecasts_trends/archive/2009/04/28/the-end-of-america-s-financial-independence.aspx

Larus
April 8, 2010 5:55 am

@Smokey
I will be prepared to reconsider my position on the decrease of Arctic ice coverage as soon as the trend reverses itself. So far we are seeing a very clear downward trend over decades of observation.
The loss of Arctic ice coverage is characterised by a statistically significant long-term trend that involves a good deal of short-term variation.
In other words, new record years have followed one another relentlessly every few years. In between the record years people like you occupy themselves with trumpeting the trend’s supposed reversal.
BTW, it’s exactly the same story with global temperatures.

JustPassing
April 8, 2010 7:08 am

Europe’s ice measurement satellite Cryosat-2 – now launched.
http://news.bbc.co.uk/1/hi/sci/tech/8606303.stm

Gus
April 8, 2010 7:16 am

arctic-roos.org has updated its ice extent graph to April 6th. It seems to show only very slight loss of extent since March 31st. It looks significantly less than the loss shown on the NSIDC graph. Has any one else noticed that?

kadaka
April 8, 2010 7:55 am

Gail Combs (05:09:29) :
REPLY:
Anthony was the one who answered the question. His temper is rather short right now because he is having to deal with a Global Warming Stalker.
(…)

Wow, that sounds unfortunate.
Running through the sub-thread, I found the reply in Przemysław Pawełczyk (01:00:12) to be in the classic “short but polite” format, I didn’t think about it when I first read it. Someone is complaining about work that wasn’t Mr. Watts, and this was summarily pointed out. Same format used in Przemysław Pawełczyk (01:13:06) when it was decided to be “irked” by the previous reply.
But then came that beautiful declaration in Alexander Feht (10:36:44) :

Those who call Mr. Pawełczyk “Mr. Unpronounceable” should think again. His name is very pronounceable and simple to those who know the rules of the Polish language. Your inability to pronounce it is an evidence of your limited education, nothing else.

Heh. The vet we’ve used for over a decade now has a long Polish last name, his main staff have worked closely with him for many years, and when asked they can provide a few “close enough” vocalizations. Take that as you will.

HR
April 8, 2010 8:56 am

Hate to spoil the party but should we really get excited about a one month blip when there are 30 years of decline in end of season ice extent to compare that with? In fact there are Norwegian observational records that suggest declines going back to the 1960’s.

April 8, 2010 8:59 am

Anu (14:44:55) :
Well, that was nice – the early Spring ice almost reached the recent “average” extent line. Brings back memories.
Now, off to the Summer melt:
http://nsidc.org/images/arcticseaicenews/20091005_Figure3.png
Will it be right around the longterm melting trendline ?
http://nsidc.org/images/arcticseaicenews/20091005_Figure2.png
Somewhere between 2007 and 2009 ?
Or is the Death Spiral speeding up the trendline, with another plunge even worse than 2007 in store ? Hard to say – the ice is thinner than this time 2007, the ocean slightly warmer, the global temperature slightly warmer, the sun (with sunspots picking up) slightly brighter – given the right winds and cloudless days, these underlying trends could combine for a massive ice loss.
But it might not be till 2013, or 2015. You can’t rush the slow train wreck of climate change.
————
REPLY: Actually, I’m still marveling at the sudden train wreck of what used to be called the “scientific consensus” for climate change!
Lots of “mights”…by 2015, we might all be dead of a mutant, recombined influenza virus or bioweapon released by a rogue state.
There is no climate emergency, just natural processes at work. If you are going to be glued to your Windows 98 tower until 2015, waiting for the Arctic to become permanently ice-free, I feel sorry for you.

Craig Stephens
April 8, 2010 9:34 am

Why is the current year ice extant compared to the average from 1979 to 2000 instead of the average from 1979 to 2009? There is such a small data set it seems wrong to cut 1/3 in any analysis. Is there no estimate of arctic sea ice over a longer period? I read a book about the rescue of the “Orca” a Whaling ship trapped in arctic ice back in 1897. The implication is that there was a detailed (but flawed) understanding of sea ice patterns more than 100 years ago.
Thanks – Craig

jorgekafkazar
April 8, 2010 11:25 am

George E. Smith (16:12:39) :
“”” jorgekafkazar (14:39:52) : [You omitted my reply to Norm, George. Why not just quote Norm directly?]
Norm Milliard (07:58:32) : “In terms of global warming, it seems the primary concern is ref(l)ectivity of the ice and I can’t believe that light knows the difference between old ice and new ice or between thick ice and thin ice.”
“Well that could be a risky wager. [Norm didn’t propose a wager, merely disbelief–jk.] The Infra-Red Handbook, has graphs of snow reflectance versus wavelength for various times after first fall; and it is pretty illuminating.”–George
George, the comment was about ice, not snow. Ice has different properties.
“That is with source and detector each 5 deg off zenith angle (specular reflection), for source and detector at 0deg and 30 deg (diffuse reflection), over that whole o.7 to 2.5 micorn range, fresh snow exhibits typically double the reflectance of 2 day old snow.” –George
Probably so, but if you’d read my comment, which you evidently didn’t, zenith angle is more important than ice or water surface condition at the poles. Zero to thirty degrees zenith angle doesn’t occur at the poles.
“Ice specially on a small scale, and maybe wet, behaves like a refractive solid, and most of the incident radiation is refracted into the solid, and at long wavelenghts absorbed by the high absorption coefficient in the LWIR.”
True, but, again, less so at polar zenith angles. Norm and Smokey were wrong and so are you, though you got it a lot closer than Norm did.

jorgekafkazar
April 8, 2010 11:30 am

Alexander Feht (10:36:44) : “…Those who call Mr. Pawełczyk “Mr. Unpronounceable” should think again. His name is very pronounceable and simple to those who know the rules of the Polish language…”
…and who can utter consonants that require pointing your tongue at your uvula.

Larus
April 8, 2010 2:07 pm

@ There is no climate emergency, just natural processes at work.
Why should that be a question of either-or? In a way, there is nothing “unnatural” about the effects of human-generated greenhouse gases or their related feedback processes. We are simply prodding climate to go a certain way, and it obliges in its lumbering way – there is nothing supernatural about it. And (naturally) the long-term effect of that is likely to be a dire climate emergency.

April 8, 2010 2:20 pm

Larus (14:07:58):
“We are simply prodding climate to go a certain way, and it obliges in its lumbering way – there is nothing supernatural about it. And (naturally) the long-term effect of that is likely to be a dire climate emergency.”
How frightening! A ‘dire climate emergency.’
Where’s your evidence?

Larus
April 8, 2010 10:54 pm

Smokey, there’s a ton of evidence of all sorts, and you know it. But I’m genuinely intrigued by your refusal to be frightened. Do you refuse to be afraid because you actually reject the evidence, or is there a different reason? (like, you just don’t care, or are the kind of person who fears nothing?) I’d really like to know.

Roger Knights
April 9, 2010 5:32 am

Larus (05:55:19) :
@Smokey
I will be prepared to reconsider my position on the decrease of Arctic ice coverage as soon as the trend reverses itself. So far we are seeing a very clear downward trend over decades of observation.
The loss of Arctic ice coverage is characterised by a statistically significant long-term trend that involves a good deal of short-term variation.
In other words, new record years have followed one another relentlessly every few years. In between the record years people like you occupy themselves with trumpeting the trend’s supposed reversal.

We’re aware that there’s been a 30-year downtrend. Prior to that there was — from what we can gather from pre-satellite information — a 30-year uptrend. Etc. This fits in with the (roughly) 60-year cycle of the Pacific Decadal Oscillation. Here’s a link to prof. Akasofu’s paper (a long but neat PDF) on the matter, “Two Natural Components of Recent Climate Change,” here:
http://people.iarc.uaf.edu/~sakasofu/little_ice_age.php

BTW, it’s exactly the same story with global temperatures.

Except for the past seven years. Or maybe even since 1995. The long-term uptrend started over 150 years ago.

Roger Knights
April 9, 2010 5:55 am

Larus (22:54:49) :
Smokey, there’s a ton of evidence of all sorts, and you know it. But I’m genuinely intrigued by your refusal to be frightened. Do you refuse to be afraid because you actually reject the evidence, or is there a different reason? (like, you just don’t care, or are the kind of person who fears nothing?) I’d really like to know.

Smokey has indefatigably & repeatedly expounded the climate-contrarian position on this site, as have others. Check the archives. (But brew up a gallon of coffee first.)

George E. Smith
April 9, 2010 11:35 am

“”” Anu (19:11:35) :
George E. Smith (16:12:39) :
So I’m not impressed by polar ice contributions to earth albedo. The reflectance isn’t high, and the irradiance isn’t either.
You might be more impressed when you realize the albedo doesn’t just apply to the infrared. “””
Well I’m not aware that I ever said that albedo only applies to the Infra-red; and certainly not in regard to that long wave IR that comprises the roughly 288 K thermal radiation from earth.
In fact albedo applies ONLY to solar spectrum reflectance. If we aren’t talking about surface reflections of “sunlight”; meaning surface of land sea and air (clouds) it isn’t albedo; it’s simply reflectance. Any reflection of atmospheric LWIR off the ground or oceans (or ice) is not a contribution to albedo. Albedo represents the fraction of the incident TSI radiation, that is reflected back into space without contributing any energy to this planet.

George E. Smith
April 9, 2010 12:15 pm

“”” jorgekafkazar (14:39:52) :
Norm Milliard (07:58:32) : “In terms of global warming, it seems the primary concern is ref(l)ectivity of the ice and I can’t believe that light knows the difference between old ice and new ice or between thick ice and thin ice.”
Some weathered ice does show a reduction in albedo, but it’s not directly related to age. Zenith angle is more important than ice or water surface condition. “””
“”” jorgekafkazar (11:25:56) :
George E. Smith (16:12:39) :
“”” jorgekafkazar (14:39:52) : [You omitted my reply to Norm, George. Why not just quote Norm directly?]
Norm Milliard (07:58:32) : “In terms of global warming, it seems the primary concern is ref(l)ectivity of the ice and I can’t believe that light knows the difference between old ice and new ice or between thick ice and thin ice.”
“Well that could be a risky wager. [Norm didn’t propose a wager, merely disbelief–jk.] The Infra-Red Handbook, has graphs of snow reflectance versus wavelength for various times after first fall; and it is pretty illuminating.”–George
George, the comment was about ice, not snow. Ice has different properties.
“That is with source and detector each 5 deg off zenith angle (specular reflection), for source and detector at 0deg and 30 deg (diffuse reflection), over that whole o.7 to 2.5 micorn range, fresh snow exhibits typically double the reflectance of 2 day old snow.” –George
Probably so, but if you’d read my comment, which you evidently didn’t, zenith angle is more important than ice or water surface condition at the poles. Zero to thirty degrees zenith angle doesn’t occur at the poles. “””
“”” Zenith angle is more important than ice or water surface condition. “””
“”” Zero to thirty degrees zenith angle doesn’t occur at the poles. “””
Well it seems I didn’t explain myself very well.
I was citing snow reflectance data from the Infra-red handbook. The first numbers I cited, were for specular reflectance off the surface, so the illumination and detection were optically disposed according to the normal laws of reflection, so only reflected light with the same magnitude angle off the (surface) zenith was measured. In the second set of numbers the illumination was at zero (surface) zenith angle, but the detected reflected light was at 30 deg (surface) zenith angle, so could only be scattered light; not specular reflectance.
So I used the term “zenith angle” rather than the more scientifically accurate “angle of incidence measured from the normal to the surface”.
Excuse me for choosing brevity over pedantry.
The reason that fresh snow turns into old snow in a few hours with lower reflectance, is that the “snow” turns into “ice”.
Single hexagonal “ice” crystals that make up “snow” melt and refreeze as a much more amorphous mass, that behaves on a macro scale, more like an optical surface, rather than a nano-particle with a size not too differnt from the wavelength of the light.
So to get back to your “zenith angle”, I concur, that when the surface consists of optically flat ice that is perpendicular to the earth’s radius, then at the pole you would not get zenith angles in the zero to 30 deg range.
But if that surface should buckle from stress, and form piled up ice masses that might have any possible surface orientation, from zero to 90 degrees relative to the mean earth surface; then regardless (or irregardless) of the sun’s altitude angle above the horizon, sunlight could impinge on arctic sea ice at any possible incidence angle from zero to 90 degrees.
And I WAS responding to Norm directly; and included YOUR shingle, ONLY to show exactly where it was that I found NORM’S statement. Since I was reading the thread from the bottom up; since the responding window is at the bottom, I naturally came upon your cut and paste before Norm’s original statement.
And finally: “”” “Well that could be a risky wager. [Norm didn’t propose a wager, merely disbelief–jk.] “””
For the following words:- ““Well that could be a risky wager.”” please substitute these:- “”Well that could be a difficult position to defend.””
Please forgive me for using figures of speech and thereby impugning Norm’s respectability; by suggesting he might be a gambling wastrel.”
“”” True, but, again, less so at polar zenith angles. Norm and Smokey were wrong and so are you, though you got it a lot closer than Norm did. “””
Is it permissable for one to read that statement of yours, as implying that Norm’s position ‘might be a difficult one to defend’ ?

April 9, 2010 5:39 pm

Larus (22:54:49) :

Smokey, there’s a ton of evidence of all sorts, and you know it. But I’m genuinely intrigued by your refusal to be frightened. Do you refuse to be afraid because you actually reject the evidence, or is there a different reason?

It’s not that I would refuse to be afraid, if there was solid, empirical evidence showing that the climate was acting abnormally. But there isn’t, and it isn’t.
Simply saying that “there’s a ton of evidence of all sorts” doesn’t make it so.
True, there are a ton of opinions out there, and there are computer climate models, and there are carefully selected tree rings, and there are retreating [and advancing] glaciers, and there are predictions that the oceans will become acid, and that the polar ice caps will melt, and claims that the sea level is rising abnormally fast, and that hurricanes will increase in intensity, and that CO2 is bleaching the corals, and so on.
All of those claims and more have been deconstructed, most of them right here on WUWT.
If you look at the situation through the eyes of a scientific skeptic, the first thing you will ask yourself is this: Is the climate outside of its long term parameters? That is the null hypothesis which must be disproved, rejected or nullified.
In other words, is there anything that can be verified with empirical [real world] evidence, based on raw data and methodologies made available to skeptics, that shows the climate is acting abnormally? Or, are the current climate fluctuations within normal historical parameters?
At first glance it might appear that each new piece of “evidence” proves AGW. But upon closer scrutiny, all the claims fall apart. Every one of them. The climate is well within its normal long term parameters. The MWP was warmer than today. The LIA was colder than today. CO2 has been many times higher in the past without triggering a catastrophe, and so on.
If the public panics at every report of a receding glacier, or discovery of a three-headed frog, or birds flying into cliffs, then it’s easy to convince worried people to open their wallets. And that’s what this scare is all about. $Billions every year, and the prospect of $Trillions, is a big incentive to sound the alarm.
I get scared about real problems, like an asteroid that will sooner or later impact the Earth: click
We’re overdue, but the funds for preparing against that emergency, like the funds drained from other areas of science, have been sucked up by the global warming scare. If an asteroid like this hits [and this was a fairly small one], it will be too late for pointing fingers.
jorgekafkazar,
You were right about the ice melt, and I was wrong. I was assuming Norm meant the annual summer/winter change in the 15% ice cover. That’s what I get for assuming. Thanks for pointing it out.

Editor
April 9, 2010 6:29 pm

In some haste – you don’t have to look for “whole of climate” things for evidence. IMHO you need to look for the things that have the potential to distinguish between natural and AGW.
CO2 traps one wavelength – does this particular wavelength show a decline in the outgoing radiation? Roy Spencer recently reported as saying No.
IPCC says warming originates in tropical troposphere (AR4 fir 9.1(c),(f)), do satellites show it happening? No, the surface has warmed more.
Until those two problems are overcome, AGW is refuted by the evidence.

Larus
April 9, 2010 11:59 pm

Smokey, thanks for replying.

April 10, 2010 5:38 am

Mike Jonas (18:29:33) :
CO2 traps one wavelength – does this particular wavelength show a decline in the outgoing radiation? Roy Spencer recently reported as saying No.

Well Spencer’s wrong, see for example:
http://www.nature.com/nature/journal/v410/n6826/abs/410355a0.html
http://www.eumetsat.int/Home/Main/Publications/Conference_and_Workshop_Proceedings/groups/cps/documents/document/pdf_conf_p50_s9_01_harries_v.pdf

Editor
April 10, 2010 4:10 pm

Phil – the body of the paper does not appear to support the abstract, and hence also does not support the associated article, at least wrt CO2 (the paper seems to concentrate mainly on methane). Average CO2 at Mauna Loa in 2006 was 381.84ppm, in 1970 I don’t have the figure but it would probably have been around 325ppm (1980 was 338.69). So, on a logarithmic scale, the increase in CO2 over the 36 years was about 2.8%. The TES and IRIS measurement graphs (black lines) for 1970 and 2006 are virtually identical in the CO2 absorption band. Also, in the CO2 band, IRIS is noticeably further below the model in 1970 than TES was in 2006 – in other words the absorption did not increase as predicted by the model.
Having said all that, I would also have to say that I doubt that any of this is all that reliable, with very small differences being examined between two measurements made in different ways. ie, maybe it hasn’t been possible to properly distinguish trend from noise and measurement variation.
OTOH, I would have thought that over 36 years, if AGW is correct, the trend (we are after all talking about 2.8% or over half of all the industrial-era CO2 increase) should have been simply obvious.

JAN
April 11, 2010 7:58 am

HR (08:56:38) :
“In fact there are Norwegian observational records that suggest declines going back to the 1960’s.”
In fact there are Norwegian observational records suggesting decline going much further back to the 1860’s. See:
http://www.climate4you.com/
(Click on “Sea Ice”, then “Sea Ice in a longer time perspective” and scroll down to the chart labeled “April Ice Extent”.)
This chart shows clearly the long term decline in ice extent since 1864 for 3 Arctic areas; NS – Nordic Seas (Atlantic area), ES – Eastern Seas (Siberian area), and WS – Western Seas (N. Canada & Alaska). From the caption: “Apparently, much of the sea ice reduction in this region occurs in concert with the termination of the Little Ice Age and the following warming during the 20th century.”
Interestingly, most reduction has taken place in the Atlantic area, and also that the reduction was faster during 19th century than during the 20th century, for all areas. Also interesting to note that there is strong covariation among the 3 areas, and that the minimums in the 1920’s, 1930’s and even late 1950’s were not much different from the 1990’s. This chart also places the satellite records from 1979 to 2000 into perspective, showing how the starting point was on the highest peak for the period since 1970.
Scrolling further down to the next graph, there is a chart showing April sea ice exent for the Atlantic sector since 1769. Here we can see that the sea ice extent in 1769 is recorded to be quite similar to that of 1995, and indeed much less than in 1866. Assuming covariation with other Arctic sectors, as shown in first graph, most likely the sea ice extent in 1769 was not much different from that seen in the 1990’s.
All this points to the fact that the sea ice extents in recent decades have not been outside of normal for previous centuries. The negative anomaly in 2007 was due to “weather”, not AGW.

Ammonite
April 19, 2010 11:32 pm

Grumpy Old Man has it right. Across short runs the noise (variability due to randomness) overwhelms the signal (purported trend(s) due to AGW). Sensible conclusions cannot be drawn over a few years of data in such circumstances. Early declarations (by non-scientists) that arctic ice would be lost in a few years post 2007 have not been supported to date. Declarations that arctic ice has ‘recovered’ in the last few years in light of the downward trend line of Average Monthly Arctic Sea Ice Extent are not that meaningful either.
Recent studies suggest that both Greenland glaciers and Antartic ice sheets are being eaten from below by increasingly warm ocean waters. This systemic attack does not bode well for arctic ice in summers to come…