This is more credible than a projection only, IMO, with the proviso of course that sea ice modeling is hard.Here is an abstract of the 2009 Wang paper that predicts a nearly sea ice free Arctic by September 2037. It is based on 6 IPCC physics based models. Also, the the top quartile prediction is 2028.
We're going to have to finish up here soon, unfortunately, but it may be worth leaving the thread with a link to [post=2374600]msg #23[/post] of thread "State of the Climate", where mheslep gave a link to the Sea Ice Outlook project at the "Arctic Research Consortium US". This was basically a competition between research groups to predict sea ice change one year in advance. A short term prediction is a rather different beast, subject to larger variations with local effects of wind and current obscuring the trends that are in many ways easier to model: but the failings of the models were intriguing.
In brief; loss of summer ice by 2040 is reasonably well founded; but given the uncertainties it might be rather more, or less, time required.
Yes, that gives a lot more weight to the projections. I'm sure all the modelers will be continuing to look at the matter and refine their models for some time yet. The one consistent feature of applying physics to the problem is that the loss of ice is not merely an aberration, but a real physically well founded consequence of changes that will be continuing to take place for many years yet.So, I feel confident that my projection is about the same as that obtained from the physics based models.
Cheers -- sylas