It could be, if some of the remaining places where polar bears find sea ice are subjected to more human pressures from shipping. But the biggest concern is that sea ice has retreated far more than we thought it was going to. That the Northwest Passage is already open suggests sea ice models might be too conservative.
Do you expect the polar bear population to keep shrinking?
We looked only to the end of this century. And based on the best estimates of future sea ice, we forecast that there would still be polar bears remaining in the Canadian Arctic Islands. Humans caused the problem, and humans can fix the problem. We predict that there will be polar bears around to repopulate their territory if sea ice comes back. It's an expression of hope.