the science suggests that it may be the case that the north pole might be ice free for a week or two in the summer by 2060. the polar regions would continue to freeze in the winter. i am not aware of any predictions of the northwest passage actually opening up year round at all. there are some suggestions that it might be open for four months some years some time in the 2100s. it's about a 2 month journey through the passage, so even a four month time window is barely usable, unless you want to winter on the other side. projections for a truly usable northwest passage are so far in the future, and would require so much unchecked global warming, that they're barely worth contemplating.
the reality is that the shipping lanes are not opening up and that, even in the worst case scenarios, it's going to be at least 100 years before this is even worth seriously talking about.
what does that actually mean, though?
it means a shipping lane full of dangerous ice bergs and unpredictable weather events. if the passage is three weeks slow in opening, or freezes over six weeks early one year due to weather, you could lose billions of dollars. nobody is going to rely on that any time in the near future.
there are real ramifications of climate change on shipping that the science supports, like an ice free, year round great lakes shipping route. hudson bay may become accessible year round.
but the reality is that the giant arctic ice sheets are not going anywhere for many decades or centuries to come - not even in worst case scenarios, which climate activists still hope to prevent.