"reconstructed" 

"reconstructed" 

Give me a proper answer. 

Are you seriously believing that anyone can reconstruct ice extent in 1137AD?
It's a joke, the last few years have shown how it can vary surprisingly in a short period, and the main reason for the catalyst 2007 decline was unusual wind patterns exporting ice. 
Surely I don't need to find again links to those beaches in North Greenland which indicate open water there much more recently that 2000 years ago. 

http://www.cbc.ca/news/canada/north/story/2013/09/03/north-barge-delays.html



"We have not seen ice with this type of coverage in quite a few years and I really don't know how far back we might've seen it," says Bill Smith, a spokesman with Northern Transportation Company Ltd., which services the communities.

"It's the opposite of what we've been seeing for the last few years where, generally, ice conditions have been improving from a transportation perspective."

Are you seriously believing that anyone can reconstruct ice extent in 1137AD?
It's a joke, the last few years have shown how it can vary surprisingly in a short period, and the main reason for the catalyst 2007 decline was unusual wind patterns exporting ice. 
Surely I don't need to find again links to those beaches in North Greenland which indicate open water there much more recently that 2000 years ago. 

Are you seriously believing that anyone can reconstruct ice extent in 1137AD?
It's a joke, the last few years have shown how it can vary surprisingly in a short period, and the main reason for the catalyst 2007 decline was unusual wind patterns exporting ice. 
Surely I don't need to find again links to those beaches in North Greenland which indicate open water there much more recently that 2000 years ago. 

I think you may be contradicting yourself a little there. First you ask if someone can seriously believe it's possible to reconstruct sea-ice extent ~1KA ago. Then you go on to make assertions for a similar timeframe that involve, er, sea ice extent!

The problem with long term reconstruction is the resolution.
We can be fairly sure in broad brush terms but if there was a ten year spell when ice was much reduced 1000 years ago there wouldn't be much evidence of it now.

No, the main reason for the losses in 2007 was the steady weakening of the ice over the last 20-30 years. If you analyse the data you will see that 2006 set new records for ice loss.

If the ice had been in its more robust state then odd wind patterns wouldn't have had much - if any - effect.

http://www.theguardian.com/environment/2010/mar/22/wind-sea-ice-loss-arctic 


Much of the record breaking loss of ice in the Arctic ocean in recent years is down to the region's swirling winds and is not a direct result of global warming, a new study reveals

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North York Moors weather 

The problem with long term reconstruction is the resolution.
We can be fairly sure in broad brush terms but if there was a ten year spell when ice was much reduced 1000 years ago there wouldn't be much evidence of it now.

No, the main reason for the losses in 2007 was the steady weakening of the ice over the last 20-30 years. If you analyse the data you will see that 2006 set new records for ice loss.

If the ice had been in its more robust state then odd wind patterns wouldn't have had much - if any - effect.

http://www.theguardian.com/environment/2010/mar/22/wind-sea-ice-loss-arctic 


Much of the record breaking loss of ice in the Arctic ocean in recent years is down to the region's swirling winds and is not a direct result of global warming, a new study reveals

Try reading the report Four. Even the headline confirms the role of climate change.

I repeat, as you seem not to have absorbed the point, that it is the thinning and weakening of the ice that has made it susceptible to these changing synoptics. Trying to divert attention from the obvious is disingenuous at best.

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Location: South Cambridgeshire
130 metres ASL
52.0N 0.1E

How are "extent" and "area" used to determine a 'total'? - or are they always treated separately?

This is "area" at present.

This appears to be a common problem with some folk GTW? They only note 'change' when they see ice disappear and do not think about how it came to be at the threshold that allows total melt out?

We see this manifest every winter as the Arctic freezes over. Certain sections of our community speak in terms of 'recovery' when they see ice area approach 'average' wiyhout any for the 'condition' of that ice.

That said the next PIOMAS data will give a better idea of how well the ice has performed this melt season by giving an idea of the 'volume' of the ice remaining?

A word of warning about this season. The Arctic does not stand alone and is connected to the rest of the planet. Any 'switch' in patterns will cover the rest of the hemisphere so any continuation of the pattern, and further years with higher ice levels, will involve similar conditions over other parts of our hemisphere. If we look around at the impacts of this different pattern we quickly see that the bigger picture is not all that rosey? If we stay in the Arctic we have to accept the heat records we saw over Canada and Siberia this summer ( and the record wildfires there) and the continuing impacts that the cryosphere suffers under such forcings.

The loss of the permafrost, and changes to albedo and surface temps that this drives, does not ,long term, help keep the sea ice at higher levels. We warm the planet, we lose the ice and the melt of the permafrost releasing the carbon it holds into the carbon cycle further plumping the planets GHG blanket.

I'm selfish and have enjoyed this summers weather here in the UK (compared to the washouts we endured post 07'?) so I'm hoping the pattern holds but in a warming world I am not going to be blinkered in the prospects for Arctic ice.

We started the season at near average ice cover and though we have seen a season conducive to ice retention we have still watched the ice dwindle away to it's present levels.

I am concerned that until we see the type of thickness' we saw through the 70's and 80's (or 50's for that matter!) we will not have the thickness levels to survive another 'perfect melt storm' year, an event that comes around every 10 to 20 yrs and so any relief at the season now finishing will be tempered with that understanding.

Finally we have the recent paper looking at the global temp rise 'slowdown' through the noughties and  pointing to a cold pacific ( warm atlantic) as being the undelying cause (with it's attendent increase in La Nina events pegging temps back) . The paper calls this a 'decadal' event and so we must be approaching it's end.....was this years pattern shift a reflection of that switch? Are we on the cusp of once again seeing rapid global temp rises ( and more frequent Nino events?) and how will a warming planet eventually impact the working of the Arctic? I hold my own understandings on this subject....... 

How are "extent" and "area" used to determine a 'total'? - or are they always treated separately?

This is "area" at present.

I prefer this version because it gives the 1979-2006 mean.

How are "extent" and "area" used to determine a 'total'? - or are they always treated separately?

This is "area" at present.

I prefer this version because it gives the 1979-2006 mean.

*There being several papers out recently correlating global warming with changes in ocean temperatures in the Pacific.

Low pressure seems about to dominate the arctic once again. The diveregence of ice it may cause may signal the end to the melt season. NSDIC usually gives their report about 5 days afterwards. September is a good month as we get two updates instead of one (the first is already out). 

There has been a major revision in the sea ice extent data on the IJIS site.  There is now an entirely new database, with the old one labelled 'Version 1' and the new one 'Version 2'

http://www.ijis.iarc.uaf.edu/en/home/seaice_extent.htm

Comparison of the two datasets here

http://www.ijis.iarc.uaf.edu/en/home/revision_v2.html

The main changes seem to be an increase in the ice extent values in the winter, more so the further back you go.

There has been a major revision in the sea ice extent data on the IJIS site.  There is now an entirely new database, with the old one labelled 'Version 1' and the new one 'Version 2'

http://www.ijis.iarc.uaf.edu/en/home/seaice_extent.htm

 

Comparison of the two datasets here

http://www.ijis.iarc.uaf.edu/en/home/revision_v2.html

The main changes seem to be an increase in the ice extent values in the winter, more so the further back you go.

Oh wow yes, in spring we even see some significantly above average extents! (2000 average that is ). The line looks smoother awell, do you think we can expect less corrections?

Incidently did the 111k super centuary drop turn out to be in error? 

The moment you have all been waiting for......

Yes its PIOMAS time!

Amazingly 2013 is above 2010 now in average thickness and volume! Still a long way to go to get back to pre 2007 levels though. This uphill climb can just as easily be undone next summer though...

 

Incidently did the 111k super centuary drop turn out to be in error? 

Yes, it became a 15k decline instead. 

 

Incidently did the 111k super centuary drop turn out to be in error? 

Yes, it became a 15k decline instead.