中国人民政治协商会议第十二届聊城市委员会委

Question

In the attached image, the Americas have been flipped. How does this affect ocean currents and world climate? I know that Europe will be much cooler without the Gulf Stream, the South Pacific Gyre will cease to exist, and the South Atlantic Gyre will be much larger, but how does this affect the climate and ecosystems of the relevant landmasses?

Answer 1

1. Climate, part I: Europe.

   • The only parts of Europe which would be much cooler are Ireland and possibly southern Great Britain. Much cooler here means maybe two degrees centigrade (or four degrees farren height) in winter.

   • Other than that, maybe the western coasts of France, Belgium, the Netherlands, and Norway might be just a little cooler, say one degree centigrade (or two degrees farren height) in winter.

     The point is that the North Atlantic Drift does not do all that much for heating western Europe. It does help a little, but the main reason why western Europe is warmer than eastern Canada and USA is that it is western Europe.

   • The bulk of Europe has nothing to do with the North Atlantic drift and won't experience any change in climate. The oceanic influence does not really extend much east of Paris or so; places like Berlin, Vienna, Saint Petersburg, Budapest, Bucharest etc. don't care much about the Atlantic ocean.

   • And, of course, the Mediterranean cities won't be affected at all.

2. Climate, part II: the Americas.

   • On the other hand, the climate of the Americas may be quite different than in the real world. Labrador and Newfoundland will be significantly warmer, because after the flip they are now on the western coast of a continent. The Rockies and the Andes will find themselves on east coast of the Americas, blocking the path of the trade winds and low to mid latitudes, but allowing the westerlies to blow across the continents at higher latitudes. I would be willing to entertain the idea that the Great Plains of North America would be a Greatest Sahara...

   • Most importantly, the hydrography of the flipped Americas would be vastly different from the hydrography of the real unflipped Americas; for example, the bulk of Brazil would be very much drier, so no Amazon...

3. Ecosystems.

   Flipping the Americas implies vastly different plate tectonics than in the real world. In the real world, the biggg major division within the placental mammals is between the Boreoeutheria who evolved in the northern Laurasia and the Atlantogenata who evolved in the southern Gondwana. (Gondwana the Mesozoic supercontinent, not Gondwana the region in India which is only a small part of the gigantic ancient landmass.)

   For example, the Platyrrhines, the New World monkeys, came from Africa rafting on storm-driven vegetation 40 million years ago when the Atlantic was much narrower than it is today. But in the Flipped Americas World, the southern Atlantic was never narrow. No monkeys in South America...

   With vastly different plate tectonic there is no chance that there was ever a Gondwana supercontinent. The entire evolution of the mammals since the early Triassic would have been different in the fictional world with the flipped Americas.

   Most strikingly, remember that during the Last Glacial Maximum Ireland and Great Britain were just parts of an enormous peninsula extending west from mainland Europe, Iceland and Greenland were very much larger, Beringia was a vast area of dry land, and the Aleutines were a continuous peninsula:

^{An impression of the World of Flipped Americas during the Last Glacial Maximum. The ice is not shown. Click to embiggen.
Own work, made based on the public domain map "Global sea levels during the last Ice Age" made by the American National Oceanic and Atmospheric Administration, and available on Wikimedia.}

North America almost touches Iceland; and the Aleutine peninsula comes close to the westernmost coast of the Greater British Peninsula... The peopling of the Americas would have happened very differently on the Flipped Americas World.

4. History.

   • At first sight, the great biggg major change in history is that in the Flipped Americas World the colonization of South America would have been delayed by centuries, and it would most likely not have been the Spanish and the Portuguese. You see, Brazil was discovered by the Portuguese in 1500 because of geography and how the trade winds work: a sailing ship going from Iberia to the Cape sails south-west with the trade winds, and continues until it crosses the Equator and intercepts the westerly winds, then turns south-east. In the real world, the turning point is necessarily not far from the coast of Brazil; but in the Flipped Americas World the ship turns south-east somewhere in middle of the Greater Southern Atlantic, nowhere near the eastern coast of South America.

     Columbus would have reached the fierce Aztec Empire instead of the unsuspecting and peaceful Antilles. Chances are he would have never returned from his expedition.

   • And the second great biggg major change in history is that the British would have colonized Flipped Alaska at some point in the Middle Ages if not earlier. See how the Aleutines come close to Ireland?

   • And then, the Polynesian expansion would have reached Flipped Brazil at some point in the 1200s if not earlier. In real history, the Polynesian expansion stopped when there were no more islands within reach of their less-than-optimal ships; but with the Pacific so much narrower, they would have had no reason to not colonize Flipped Brazil. And Flipped Brazil has ample resources of wood and rubber and so on, so it is perfectly imaginable that the Polynesians would have established a cross-Pacific trade network supplying Brazilian goods to China. And China would have been incentivized to take over this trade route for itself. A Chinese empire in Flipped Brazil...

Answer 2

There will be a "Gulf Stream", and Europe will be heated. Little less because of the smaller gap, and most heating goes to Alaska, but will be there. The Arctic will be colder because the "Gulf Stream" does not go there-very cold Russia(if it exists). Mountains on East America means less rain in interior, cold stream on west means America is lots colder and arid. The Sahara drops dust on the Atlantic not on the Amazon, which means there is not big vegetation there. Maybe the Amazon is a sand desert if the North Pacific current circle reaches there and makes all Central America colder for 10' or even 20'K. Cold current from Antarctic make South America very cold-no mountains protection against it. El Nino/La Nina on Atlantic - dunno how to even think about it.

One more thing - less distance between North America and Europe means early conquest. Especially with that line of islands between Ireland and Alaska (heated by "Gulf Stream" with quite nice climate) then have islands from tip of South America to Australia. Think all World will be mapped before X century, maybe even BC...