Who are the major powers please and what type of state do they have? I.e. republican, constitutional monarchy, aristocratic, some form of autocratic system or what?
The USNA, Russia, Germany, Japan, Australia, Greenland, and Iceland. All are Democracies
Assuming that USNA occupies most/all of N America?
Having Iceland and Green especially up there suggests that some dramatic changes as in our world neither have the basis for substantial populations or economic bases. Is Greenland still largely ice covered or is a lot of it dry land in your world?
Having Russia and Japan especially as democracies - especially if it means no monarchy - are substantial changes. Also in our world all of those bar Japan would be predominantly white European societies which could be ominous for the rest of the world.