Did anyone here actually read the OP's article? It seems not. The phrase "effectively ice-free" refers to thin, fractured ice being judged solid ice cover from a satellite's perspective. Such ice allows for the movement of vessels and responds quite differently to winds and sea currents. The article is NOT suggesting that the Arctic is actually ice free in summer. 22 pages in and the central argument of the OP doesn't seem to have been seen by anyone.
Thin fractured ice eh?? How THICK is "multi-year" arctic sea ice?? Say 5 yr ice or 10 yr ice?
Then compare that to the WestAntarcticIceSheets that spill off the coast there....