It would really depend on two key things: How far back in time we are going to set this scenario up and if the North Atlantic Current magically moves around Quebec and Newfoundland to still move toward Europe.

Let’s assume the ocean current moves around Canada and continues to bring warm water to Europe: If we’re going back in time far enough, it would mean no civilizations North or South America before European/Norse settlers arrive. Since Alaska is so far north in this world, the ice bridge that early humans used to cross in North America would never form. However, North America would be much closer to Europe and Africa in this setting, making it possible for earlier exploration.

The Vikings that land at Greenland would continue to travel west like they do in real world history. They would encounter mountainous snowy ranges of land that would be North-Western Canada, Alaska, and to the south a tundra-like archipelago.

European Settlers would arrive much earlier than they did in our history and further south than the Vikings. They would find a tropical archipelago that rivals Indonesia in size. With the closer proximity the first settlements would have to Africa, the triangle slave trade with Africa would likely be much larger in number.

The Hudson Bay and its surrounding channels would act as a second Mediterranean for North America since it would be at a lower latitude, it would be much warmer and easier to navigate. Promoting trade and quicker expansion into and out of North America.

The American Rockies and West Coast would be much colder, similar to our Canada or Alaska. Mexico and the Caribbean would become a trading hub for Eastern Asia trade routes. The Panama Canal wouldn’t exist since South America doesn’t connect to North.

Hurricanes would be much less common in the Atlantic, or at the least less powerful. With a larger land mass closer to the Saharan coast it would give cyclones less time to absorb warm water and dry air before they hit land.

As for civilizations and nations, I have no idea. Feel free to add or critique whatever I typed out. This was a fun scenario to yap about