If Global Warming was to occur it would affect all of the regions differently. Some places it would affect of lots of things and some only a couple or not at all.
Cordillera- Global warming would affect the Cordillera region, the population would be more dense and there would be no room for anything. On one side of the Cordillera region there is like a wall of mountains so the population can’t spread out.
Interior Plains- Global warming would not affect the Interior Plains, global warming would allow the population to settle more up North.
Canadian Shield Region- Global warming would not create any problems in the Canadian shield. If global warming was to occur it would allow the population for the Shield region to be able to settle and spread out more.
Appalachian Region- If global warming was to occur, the Appalachian regions would have more room for settlement because they could spread out and move up into the Canadian shield.
St. Lawrence Lowlands- Global warming would create problems in this region, because the temperature would increase so lots of people would move there. Also there is a lot of agriculture so the population would go up.
Arctic- There would be problems if global warming was to occur, the temperature would go up so the ice would start melting and the animals wouldn’t be able to survive. But also if the temperature went up we would be able to spread out.
Remember that for the Shield, Canadians already don’t want to live there because of the topography so an increased temperature wouldn’t change it much.
In the Arctic, if we use the temperature map of Canada, it probably still wouldn’t warm up enough for people to want to live there. The furthest north we’d go is probably into the NWT.
Also, keep in mind that density is what may bring problems with settlement.
You forgot to state your assumptions about where people settle. This would help your reader to understand how you came to these conclusions.