I’d imagine places like Svalbard. Technically it’s inhabitable now, and has been for decades but it’s the most Northern year round sustained population on the globe.
Further North is Arctic tundra and there isn’t a sustained population. Maybe he’s referring to areas like that.
Though I will say that back in 2019 I saw an article about how every winter a bunch of Reindeer in Svalbard die due to climate change. As the spring rolls in and snow melts, Reindeer corpses are left behind in the fields 🥺.