|The sharp shrinkage of Arctic ice is evident versus the yellow average./NBC|
Here's some likely fallout.
First, this is going to increase the push for "Northwest Passage" commercial shipping. In turn, the soot from marine diesel in the summer will further accelerate ice melt. And, that itself will be a vicious circle of feedback in the summer, in ways that may not yet be fully known to the degree Arctic currents change.
Second, that push will possibly exacerbate international tensions. Canada has made quite clear that it will keep a strict watch on border issues for ships attempting the passage, including against the Colossus of the South, the US of A.
Third, Canada, the US, Russia for sure, possibly Norway and possibly Greenland and/or Denmark, are all going to look to further expand Arctic oil exploration, which we really don't need for multiple reasons. Add in wrangling over continental shelf issues, highlighted by Russia planting its flag, via submarine, on the North Pole seabed, and this could get dicey.
Fourth, as noted above, this will likely affect currents at some point. I'm no scientist, so I don't know how, and certainly don't know whether western Europe would be plunged into a short-term winter freeze. But, other things could be affected, like fish stocks in the Grand Banks, which aren't fantastic right now anyway.