It doesn't need to be made about the arctic circle anyways. While we can argue until the cows come how about hurricanes and the California drought and things like that, there is no ambiguity about the arctic - it has severely warmed and this is having drastic changes on local weather and ecosystems. Salmon aren't an isolated case, every species up there has been severely screwed up.
A near-total majority of scientists who study the climate say humans are causing climate change and the opposition is a mix of people paid by the fossil fuel industry, conservatives motivated by tribal loyalties to make another tedious attack on environmentalists, and would-be contrarians who may or may not realize they've been duped by the previous two groups.
The only debate is how much further death and destruction will be caused by the short-term profit crowd.