Looking at the average thickness graph, I can see why it may be more than just a few year to an ice free arctic. It has taken close to 30 years to lose 1 meter and there is still just over 1 meter to go.

Useful to remember that multi - year ice is still a very significant portion of the total during the September minimum. Wondering if multi-year ice will disappear all at once, or if there will be a gradual reduction in the oldest ice first. That is could we expect to have a time in the near future where only First, 2nd, 3rd and 4th year ice is present or will it all be gone in 1 summer?

Somewhat off topic, but a report has come out about the first sailboat to traverse the Northwest Passage. Several nice photos including one from site of graves from Franklin expedition. http://belzebub2.com/?lang=en http://www.cbc.ca/news/canada/north/story/2012/08/29/north-northwest-passage-sailors.html

Best way I know to create images is to use Paint.net. For Excel stuff, just paste it and then resize to 420 pixels wide. Then post it to a blog and use the img src="....." line of html (include < before and > after).

The 90 day surface temp anomaly map shows below normal temps over most of the Bering and portions of the Chukchi and Beaufort seas. However, these areas almost always melt out. So, ice formation this winter over the rest of the Arctic was likely below normal; especially the Barents and Kara seas.

Walt Meier is stating that the ice is only 10 to 30 cm thick at most (4 to 12 inches)! http://earthobservatory.nasa.gov/IOTD/view.php?id=77513

The volume of ice melt is not related by any simple mathematical expression to atmospheric temperatures. This is because, the Arctic is so large and there are many other factors as well. For example, ocean currents and temperature play a role as does the mechanical properties of ice as it breaks up. The intensity and direction of the wind can either enhance or diminish the export of ice from the Arctic to southern (and warmer) waters. Finally, ice itself tends to keep the ocean heat contained within the ocean. So, in some respects, melting of ice results in greater export of heat from the Arctic and cooler temperatures.

One problem with extrapolating the PIOMAS data is that there is a possibility that the data set contains a bias that is growing over time. The system works by measuring the time difference for microwaves bouncing off the ice and the water. However, there are also melt ponds on the ice which could be throwing off these measurements. More melt ponds could mean a greater bias.

JC; One reason why there is so much data over the last 30+ years is we only have good satellite data starting from 1979.

It maybe that something else has happened with 2010 and 2011. Both of these years show a dramatic late season loss followed by a later recovery. Could it be that melt ponds are becoming much more common and in turn are not being measured by the satellites accurately? Alternatively, the melt ponds may be occurring earlier in the season of 2010 and 11. I'm suggesting this because it seems very odd that the amount of melting in the 2nd part of the season has fallen so much for 2010 & 2011.

So, this paper is stating that in the past 12 years, despite warming temps and melting ice, there has been a net cooling of the ice sheet from more fresh snow in some areas. However, with a little bit more continued warming, the albedo will shift so that higher elevation dry areas begin to feed back positively and result in net warming over the entire sheet. In other words, the sheet has not reached a state of maximum melting, since it's only the lower elevation area that have positive feedbacks.