It's an excellent question.
The reality of climate change is that while there will be times when there are open navigation transits through the Northwest Passage in the height of the summer navigation season, the reality is that climate change actually increases the unpredictability. There is an Arctic gyre that tends to move the ice up against the western edge of the Arctic archipelago, and that includes lots of old ice inclusions and icebergs that can create navigational difficulties even in the summer navigation season. As well, we can see that the effects of climate change can create storms and other phenomena that complicate the situation in the north.
Climate change is not something that's necessarily going to make the north more accessible at sea. It makes it more unpredictable, and in some ways more dangerous.