This is my first time really using stack exchange so yeah. forgive me if i messed something up or if im not using it right.

Ive been making an alternate earth and i have repeatedly stumbled upon an issue regarding ocean currents, especially in the North Atlantic. How would ocean currents work here if a large landmass or continent in the North Atlantic work? Would the gulf stream be diverted up the Continent, leaving North America without a warm current (or even any current?). Or would something else happen?

Below is an example of what i mean by North Atlantic Continent, from my alternate earth.enter image description here

  • $\begingroup$ A concern is that without topography of the oceans answers are going to be more speculative. For example between Newfoundland and the mid Atlantic ridge there seem to be a fair number of islands, historically there is a large shallow bank there, Is that all completely shallow? That would block major currents traveling through there. $\endgroup$ Apr 5 at 19:45
  • $\begingroup$ @PurePerfection786 i believe this would destroy the current that is responsible for heating up europe without it would probably be really cold there. Though the exact implications are unclear as a giant continent in the middle of the Atlantic changes probably a lot of the weather in your world. $\endgroup$ Apr 5 at 20:08
  • $\begingroup$ Without the Gulfstream being what it is, Great Britain and Ireland and northern France would be just about as warm and fertile and productive as Newfoundland... But anyway, the biggg problem is that to have a continent snaking on the middle of the Atlantic you will need to change everything about how the Americas and Europe came to be the Americas and Europe. That is to say, why do you have the same coastlines for Europe and Africa and the Americas when you have that sinusoidal continent midway? It makes no sense. $\endgroup$
    – AlexP
    Apr 5 at 20:45
  • $\begingroup$ This is a remarkably complex question that probably violates the help center's Book Rule (too broad). Notably with the level of complexity you've provided (kudos for that, BTW, we don't often see that level of detail). For one thing, there would be no north Atlantic gyre. And without it, probably no gulf stream at all. Ugh. The more I think about it the more this violates the book rule: literally a book could be written about this and the answer would still be inadequate. $\endgroup$
    – JBH
    Apr 6 at 8:00
  • $\begingroup$ And this might mess up the current that is flowing up from the south Atlantic into the Gulf of Mexico with the result that the Gulf might be much warmer than it is today. The weather changes would be huge. VTC as this changes too many things to be able to answer. $\endgroup$
    – David R
    Apr 6 at 14:36

1 Answer 1


Would the gulf stream be diverted up the Continent, leaving North America without a warm current?

The Gulf Stream's water flows to Europe now. Your proposal would either stop or divert it, and Europe would become much much colder.

You should start with a map of how all the currents flow now, and consider how your giant dam would disrupt the current situation.

enter image description here — From Gulf Stream - Wikipedia

But you also need to consider the geography of the land masses.

Notice how the two sides of the Atlantic have very similar profiles. The two landmasses were originally connected, and over time they drifted apart. That leaves you with two choices:

  • There were to giant faults, one on each side of the new island, so its west side will need to look like it was ripped off the Americas, and the American coastline will have to be reshaped accordingly. Ditto for the east side and Europe/Africa.
  • If you preserve the current shapes, your new island must have built up later, from massive volcanic eruptions along the fault line between the two tectonic plates. Your island will need to look like that is how it was formed.

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