I wouldn't be surprised in the least if 2015 caught up to 2012.
In 2012.....the central part of Canada (north to south) was VERY WARM. This was the year that the US set all kinds of crazy records in March of 2012 (the LOW for one day for Marquette, Michigan was higher than the OLD RECORD HIGH).
A couple things stick out for me in looking at the above maps:
1) The concentration levels of 2015 are lower than 2012
2) The Beaufort, Hudson Bay, and areas around Greenland are the areas where 2012 was way ahead of 2015.
3) The Chukchi sea is the one area where 2015 is way ahead of 2012. And that MAY prove to be critical...as it allows more warm Pacific waters to melt away the ice in the Beaufort and the CAB on that side of the Arctic.
Again....won't be surprised EITHER WAY....it is only a waiting game....and the game is winding down to the last few minutes (years) before the Arctic ice is gone at the end of melt season. This year.....highly doubtful. 2016....possibly (again...I think MOST of the ice will be gone next year)....2017....2018?
I do know that the ice is SUSEPTIBLE to "going" WITHIN the next few years....and I suspect most of it will be gone (except for a smattering here and there) by NEXT September.