To continue the discussion on the quantitative effects of Nares export, if volume lost is indeed around 1km3 per day, having the strait open for an extra of 3-4 months this year means the extra export of roughly 100 km3 over the season. OTOH, if the ice had not been exported it still would have lost some of its thickness to bottom and top melt, so the net volume lost to export should be around 60 km3. As the minimum volume of the CAB in September can often reach 4000 km3, and in 2012 reached 3400 km3, the loss amounts to 1.5%-2% of the volume at minimum. Not negligible, though not decisive either.
Of course, there are the qualitative effects of export - making the ice in the Lincoln Sea mobile, perhaps making it more vulnerable to waves and winds, potentially increasing Fram export through unlocking of the whole ice pack in the region, and more.
Note: if anyone can come up with better measurements to the numbers used in the quantitative estimate that would be appreciated.