Great Lakes Earth Map--And the Questions that Come With It

[JohnDailey]

Dark brown=mountains. Light brown=uplifts. Black=Igneous provinces still visible today at their original extent with no consideration of erosion.




Let us say that, in the future, some scientists have created satellites capable of something that seems science fiction for now — punching the walls of the universe to study an alternate reality. By that scenario, some hundreds of “alternate Earths” from hundreds of alternate universes would already have been discovered and meticulously studied. As much as half of them would still be ruled by humans, unfolded by events that turned out differently. One universe, for example, had an Earth where 9/11 never happened, or where the outcome of the Revolutionary and Civil Wars ended up differently.

One of the most interesting to note was a planet that scientists call “Alternate Earth 111”, known to the public as “Great Lakes Earth”.

Why?

Because at first glance, it seemed that almost every continent is dominated by lakes, even those larger than the Great Lakes that we have in North America.


The Americas
The Appalachian Range used to exist, but all that remains nowadays are their metamorphic bedrocks. Since then, the Atlantic Coast is a labyrinth of islands, straits, channels and sounds, making New England the eastern equivalent of the Inside Passage, caused by five million years of being repeatedly scraped and bulldozed by ice. The terrain is not quite dramatic, the tallest above sea level being only 122.2 feet (37.25 meters.)

While our Rockies stand no taller than 14,440 feet above sea level, the tallest peak in a Great Lakes Rockies is measured to be 20,310 feet. Back home, our Rockies formed between 80 and 55 million years ago through the Laramide Orogeny, the subduction of the North American and Pacific plates at a shallow angle. Their Rockies first formed 55 million years ago as the result of a collision between eastern and western North America. They stopped becoming active as recently as nine million years ago. Since then, a series of faulting had shed off the mountains’ sedimentary skin and exposed the tougher granite-and-gneiss core. No wonder, then, that transdimensional explorer Mark Greene called the Great Lakes Earth Rockies “a single, continuous spine of breathtaking Tetons.” West of the Rockies stands an uplift varying in elevation above sea level between 2,000 and 13,000 feet (between 610 and 3962 meters.)

Minor differences in geological history could create major differences in geographical shape. Without the Cascades or the Alaska Range, the distinctively whiplike Alaskan Peninsula simply does not exist. The area we’d recognize as San Andreas (Baja Peninsula and southwestern California) is fused into what we’d call southeastern Alaska. Evidence in the rocks beneath the soil shows that San Andreas did indeed collide with Alaska only 24 million years ago, but the mountain-building period did not last long, and the peaks were reduced into quarter-mile-tall hills.

The Black Hills of South Dakota don’t exist on Great Lakes Earth. The Ozarks, larger in area and elevation than back home, are the closest analogy. The tallest stands 7242 feet (2207 meters) above sea level. They started life as a dome of granite that, over millions of years, had been replenished with fresh supplies of magma. This allowed the crystals that made the granite dramatically larger, making the rock itself a lot harder. After 2.2 billion years under the surface, the dome popped above sea level only as recently as 20 million years ago. Even though rain and river played a part in carving the dome into numerous spires, pillars and gorges, the real player in shaping the Ozarks is lower air pressure, exfoliating the surface into pieces like layers of onions.

True to the spirit of the planet’s name, North America is full of large lakes. The largest of which is Agassiz. In fact, it is the cornerstone of all of Great Lakes Earth’s great lakes — enormous depressions, tectonic rifts or volcanic calderas reshaped and filled in by ice, rain and river. To have an idea on the shape, size and scope of Agassiz, we must look at the familiar faces of the Great Lakes — Superior, Michigan, Huron, Erie and Ontario — and then flood off the entire basin. This is Lake Agassiz, 95,000 square miles and 5500 feet at its deepest. Agassiz started out as a series of rifts and faults that failed to split the continent. The valley wouldn’t become a lake until the ice bulldozed the depressions during the Pleistocene glaciations.

West of the Rockies, there are even more lakes—Bonneville, Carson, Olympia, Hamilton and Red Deer. All of them formed separately late during the Cenozoic as tectonic weaknesses sank the land, sometimes to the point below sea level. Further shaping the lakes were the last five million years of ice ages strengthening and weakening the freeze-thaw cycles. As a result, not only do they have their distinctive shapes, they are also deep. Bonneville, the deepest, is currently over a thousand feet deep.

What we’d presume to be the Brooks Range in northern Alaska actually isn’t. The Murchison Mountains, as we call them, are actually volcanic peaks standing 14,411 feet (4392 meters) above sea level at the tallest. They stand at one of the points where the Arctic Plate sinks beneath the Laurasian Plate.

The Yellowstone mantle plume is still present. Except that instead of Wyoming’s northwestern corner, it can be found in northeastern California. The upland itself covers an area of 5,000 square miles and stands almost like an island between the surrounding lakes and lowlands.

Five million years ago, the oceanic Panamanian Plate had been invaded on both fronts—by the Caribbean Plate in the northeast and the Pacific Plate in the southwest. This uplifted the basaltic slab to above sea level and had volcanoes guarding the plateau. The Twins, as they are called, are still active. One twin is currently 6,684 feet above sea level, the other 9,698 feet. Curiously, the Twins make up the coastline of Central America on Great Lakes Earth, which makes sense considering their young age. What doesn’t make sense is how they could be so tall in so short a time. The same problem is said of the Andes, which also make up South America’s entire western coastline. But if we look at a bathymetrical map, we start to understand why—from Argentina to Guatemala, the Pacific Plate is paralleled by the younger, narrower Nazca Plate. It first formed only ten million years ago and uplifted the Andean coastline for five million years before reaching the Panamanian Plate. This double-subduction may explain why the Andes, 25,122 feet above sea level and still rising, as they have been for the last 45 million years, had such devastating eruptions in the last 10,000 years, with an average of one eruption measuring eight on the VEI every thousand years.


Questions follow:

Are these changes enough to spare northeastern Nebraska from the onslaught of Tornado Alley without sacrificing the Midwest’s prairie fertility in the process?
Will all these lakes and rivers (not pictured) turn the Wild West into a greener Eden?
How much of the Amazon Basin will still be rainforest?



Eurasia
Physically absent in the supercontinent are Turkey, Iran, and the Low Countries (Belgium, Netherlands, Luxemburg and Denmark). Back home, Scandinavia is one of Earth’s recognizable peninsulas. On Great Lakes Earth, the body we’d recognize as the Baltic Sea is actually known as the Baltic Plain.

The dominating feature of Asia is a large region of basaltic rock, the Siberian Traps. It formed as a series of eruptions spewed out lava 60 to 43 million years ago. Since most of northern Asia was a receding series of shallow seas at the time, the eruptions resulted in all four compositions of lava—low on both gas and viscosity, high on gas but low on viscosity, low on gas but high on viscosity and high on both gas and viscosity. However, 96% of those eruptions happened underwater, so they wouldn't react exactly like they would on land. Each eruption could last anywhere between 10,000 and 60,000 years, with breaks varying between 30,000 and 80,000 years. When the last eruption had finished, seven million square miles of Eurasia were buried under four million cubic miles of lava.

Eurasia is subject to Great Lakes Earth’s largest sea, one that we used to have back home — the Tethys. Back home, the Mediterranean has an average depth of 1500 meters and a maximum of 5267. The Tethys’ depth is 1205 meters on average and 7,000 maximum. Even so, the ratio between deep and shallow water is remarkably similar to that of the Mediterranean — more or less than 45% of the sea is no deeper than 200 meters (the required maximum depth for a sea to be “shallow”). It’s also connected to two oceans with two different personalities — the Indian to the east and the Atlantic to the west. What we’d recognize as the Arabian Peninsula is, on Great Lakes Earth, an extension of northeastern Africa, erasing both the Red Sea and the Gulf of Aden out of existence. This further widens the passage from the Indian Ocean to the Tethys.

The island of Newfoundland is the southeastern extension of Iceland. It stands at a point where a stationary mantle plume, loaded with silicon, stands at a crossroads between the Mid-Atlantic Ridge and the edge of the Arctic Plate. Unlike our Iceland, in which the Ridge has split it in east-west, the Iceland of Great Lakes Earth is split in a north-south division.

In Asia, what looks to us like Borneo is a big extension of eastern India, erasing the Bay of Bengal from the map. Sumatra is an extension of India’s western coast. The rest of Indonesia, as well as the island chain of the Philippines and the Malay Peninsula, don’t exist.

Back home, the Himalayan range in Asia is impressive enough. On Great Lakes Earth, they are even more so. The highest peak, Kailash, stands 33,500 feet (10,210.8 meters) above sea level and still rising. If the base of Mauna Kea in Hawaii were above sea level, this would have been its equal. Their Himalayas are older than ours, if the differences in height suggest anything. Ours first formed 50 million years ago. Theirs rose from the plains between 65 and 70 million years ago.

65 million years ago, sub-Himalayan Asia was subject to a series of lava eruptions lasting a total of 30,000 years. When it was all over, the lava covered a thickness exceeding one mile, an area of one-and-a-half million square miles and a volume greater than one million cubic miles.

The islands of Japan on Great Lakes Earth are the result of multiple faults and subductive hot spots, stationary mantle plumes standing in the intersections of colliding plates. Japan, consisting of six large hotspots, stands three miles southeast of the Laurasian Plate and five northwest of the Pacific Plate. The fact that the mountains make up the coastlines suggest that Japan on Great Lakes Earth formed very recently—no longer, it’s been surmised, than 11 million years. Like the Andes, Japan was subject to massive, earth-destroying eruptions.

The Alps remain tall, as they are back home. However, they are formed as the result of a piece of Africa, known to us as Balk, colliding with southeastern Europe 40 million years ago. Currently, the range’s highest peak, Olympus, stands 22,838 feet (6961 meters) above sea level and is still rising. Behind the Alps is a plateau that covers lands we’d recognize as Romania, Moldova, Slovenia, Austria, Slovakia and Hungary. Also, Balk’s terrain on Great Lakes Earth consists of plains and hills rather than mountain ranges like back home.

The Scandes, stretching the length of the northern Scandinavian coast, are the results of ocean/continent collisions — volcanoes. They are also taller than they are back home — 18,510 feet (5642 meters) above sea level and still rising.

The Ural, Caucasus, Pyrenees and Apennine mountain chains used to exist on Great Lakes Earth, but not anymore.

Questions follow:

With open connections to both the Indian and the Atlantic, what would the Tethys’s personality be?
Will a higher Himalayas — which means a higher Tibetan Plateau — pose any noticeable differences on India’s climate, precipitation and landscape?
Would adding Borneo and Sumatra pose any difference to the climate and landscape of the Indian subcontinent?
With the rest of Indonesia, the Philippines and the Malay Peninsula out of existence, how would this absence affect ocean currents?
How would all this added water affect the Mediterranean Basin as well as the Indian monsoon?
Concerning the Siberian Traps, 40 million years of erosion would mean an altogether different Russian landscape, no doubt, but to what extent? Would we still see vast, singular bands of boreal forests and steppes, or would we expect to see Russia hosting a wider variety of habitats?
Would a larger Deccan Traps pose any difference to the 65 million years of erosion?
How would the changes in mountain building and coastlining affect the climate and landscape of the rest of Europe?



Africa
Like some of the other continents, Africa has its share of great lakes — Chad, Congo and Makgadikgadi. Lake Makgadikgadi, the southernmost, is also the youngest—100 feet (30 meters) at the deepest and formed as water flowing from the Aden Bahçesi inundated a series of fault lines only three million years ago.

The Atlas Mountains used to exist on Great Lakes Earth, but not anymore.

The defining mountain range of Africa is the Aden Bahçesi, which first formed 45 million years ago as the Indian Plate sank beneath the African Plate. Currently, the tallest peak stands 21,810 feet (6647.7 meters) above sea level and still rising.

Lakes Chad and Congo had a shared history. They originated less than 200 million years ago as a series of horsts and grabens that would quickly be inundated aftewards. It wasn’t until 80 million years ago, when the seafloor slowed down and sea levels began to recede, that perhaps the deepest points on Great Lakes Earth during the Cretaceous period became surrounded by dry land. In time, freshwater diluted the lakes, pushing the salinity deeper and deeper. Today, Lake Congo to the south averages 221 meters deep, with a maximum of 2001 meters, the bottommost 15 feet being brine. Lake Chad to the north has an average depth of 337.5 meters with a maximum of 3791 meters, with the Pharaoh’s Brine taking up the bottom 20 meters.

Questions follow:

Are any of these changes enough to turn North and South Africa from desert to more verdant habitat, like savanna?
Would having a tropical megalake be enough to make a noticeable difference to the equatorial climate of the Congo rainforest?



Australia
First and foremost, it’s not called “Australia” in Great Lakes Earth, but rather “Sahul”. The first major difference is the presence of Lake Eyre, a body of fresh water over 460,000 square miles in area and 49 meters at the deepest.

The northern and eastern coasts of Sahul are worth noticing. To the northwest, it looks as though the two main islands of New Zealand are glued into the mainland. It’d also look as though someone were shoving the island of New Guinea down the throat of mainland Australia, known geographically as the Gulf of Carpentaria. The northern and eastern extremes of Sahul are defined by volcanic mountains, the tallest standing 18,500 feet above sea level.

The final difference is that Sahul is much further south than Australia. So much so, in fact, that by comparison, the distance between it and Antarctica is cut by half.

Questions follow:

Will the Outback still be desert?
In the same scenario, Indonesia and the Philippines don’t exist. What kind of ocean current(s) would one expect to see influencing Sahul?
What kind of climatic and ecological influences would we expect Lake Eyre and the continent’s closer proximity to Antarctica to create?



Pole to Pole
Compared to our oceans, the Arctic Ocean of Great Lakes Earth seems to have a little elbow room. The reason — the Atlantic on Great Lakes Earth is wider than ours by over 1350 miles. Africa, Eurasia and Sahul have, compared to our Old World, moved that far eastward, creating a landbridge that connects Asia to North America, erasing the Bering Strait off the map and shrinking the Bering Sea. To that extent, it would be like turning the Russian urban locality of Egvekinot (66.3205 degrees North and 179.1184 degrees West) into the next-door neighbor of Teller, Alaska. But that is in our eyes only. On Great Lakes Earth, North America has always been a part of Laurasia for 250 million years.

The island of Greenland looks, to us, rearranged to the extent that Mont Forel, the island’s highest peak, is located in 90 degrees North — the North Geographic Pole.

There is another difference, one that applies also to the Southern Ocean surrounding Antarctica. Back home, the Arctic’s average depth is only 1205 meters, whereas its deepest point is 5,625 meters. The Southern Ocean averages 4,000 meters deep and has a maximum depth of 7,235. On Great Lakes Earth, the Arctic averages 663 meters deep with a maximum of 7235 meters, whereas the Southern Ocean averages 2212 meters deep with a maximum depth of 5625 meters.

Then, of course, there is the Arctic Plate, something that doesn’t exist back home. Horizontally cutting Iceland in half, we can find the border straddling the coasts of Baffin Island, Alaska, and Scandinavia, creating the Scandes and the Murchison mountains.

Questions follow:

How would these differences affect ocean currents and polar landscapes?
Could any of these changes have influenced the global average temperature and precipitation? If so, to what extent?



Ocean Deep
Back home, the Pacific Ocean, the largest of the five, has an average depth of 4028 meters and a maximum of 10,924 meters. On Great Lakes Earth, the Pacific’s depth averages 2025 meters  and the maximum is now 8486 meters.

Back home, the Indian Ocean averages around 3963 meters deep with a maximum depth of 7258. On Great Lakes Earth, the Indian Ocean averages around 1467 meters deep and has a maximum depth of 7906 meters.

The Atlantic Ocean back home has an average depth of 3926 meters and a maximum of 8605 meters. On Great Lakes Earth, its average depth is now 1725 meters, and the maximum is now 10,911 meters, the same as the Pacific.

Questions follow:

How would the changes in depth affect ocean currents, therefore the global climate?

[Mechalich]

So, um, you've dramatically rewritten Earth's geology in a large number of idiosyncratic ways by adding together fiat changes that do not appear to comport directly to any specific model system. As such, the only thing to say is that everything would change in massive ways. Properly answering even one of your questions is a wholly reasonable way would take immense effort (or a really awesome computer program, but I'm not aware of any).

Why, exactly are you doing this? And at what scale to the answers matter? For the purposes of most fantasy worlds you only really need to model the climate on one continent or region (an area roughly the size of Australia handles it) and you can largely ignore the rest.

If you want an alternate earth with a large number of massive lakes, I feel like there's probably a much less complicated way to get it. I think you could get that effect simply by reducing overall continental elevation ranges and thereby having 'flatter' continents.

[Eldan]

I mean, you could put in the Hadley cells and make some very broad guesses about dry and wet areas, but that's about all you can do without endless amounts of work.

[Lacuna Caster]

It's an interesting thought-experiment, sure, but yeah, any of the questions you've asked would take a trained climatologist to even begin answering.

Have you taken a look at DeGenesis, out of curiosity? It's kind of similar in outline, with large portions of the earth's surface reshaped by a series of meteor impacts that also introduced mutagenic alien life along with an incipient ice age, though over a much shorter time-frame. Main focus is on culture and biology rather than climate science, but maybe it would give you some ideas?

[JohnDailey]

Why, exactly are you doing this? And at what scale to the answers matter? For the purposes of most fantasy worlds you only really need to model the climate on one continent or region (an area roughly the size of Australia handles it) and you can largely ignore the rest.

This is for a worldbuilding/alternate history textbook. And of course they matter because if the world isn't believable, then neither will the stories. No, I can't ignore three-quarters of the world because the global climatic system is interconnected.

[nineGardens]

This is for a worldbuilding/alternate history textbook.

Okay, so when you say a worldbuilding/alternate history textbook, do you mean a textbook on HOW TO do alternate histories?
Or a textbook that exists inside and alternate history you are writing?

And of course they matter because if the world isn't believable, then neither will the stories.

Okay... so I think it is worth considering here that "Believable" and "Perfectly scientifically accurate" are very very different bars.
What I mean by that is that 99% of your audience are not climetoligists. They do not know the first thing about how the climate works. If you make a story that is "Believable" to the 99% of the population who are not climatoligists, then you have done a pretty good job of believable.

If you then set you sights a little higher, and do some sensible LOCAL modelling (Oh look, a lake made central africa less desserty, because that IS how weather works") then you have probably made it convincing enough for 99.99% of the population.

If you have described a climactic system well enough that it would take a full scale global mathematical modelling in order to dispute your claim, then I think it counts as believable.

And more to the point:
Stories primarily lose believably not because of the science, but because of the characters.
Harry Potter loses significant believability not because there is magic in the story, but because Time turners are significantly underutilized by the main characters, who all know of their existence, yet don't make use of it nearly all the time. Or, perhaps more accurately, it loses believablity because a student is given a time machine in order to attended all her classes. The time machine itself we all accept.

You are right- the world does need to be believable, and in turn, the climate needs to be believable... but there are a million and one things that can break believably in a story, and as long as your climate is PLAUSIBLE you are good enough.

More to the point, if less Tornado Alley gives you the story you want, then just state "There are climate/geological details that make this work", and unless your story is REALLY centered in on the climate, people are willing to accept.

No, I can't ignore three-quarters of the world because the global climatic system is interconnected.

Well sure, you are right...
But unless your story is world spanning, you can just handwave and say "The rest of the worlds climate is such a shape as to make THIS part of the climate behave in the way my story needs it."

Unless your main character is a climatologist, it is unlikely that your stories are going to provide enough details that even a trained climate expert will be able to point to a contradiction.

It's like.... if you pick up a card from a deck of cards and say "This is the four of hearts"- unless you ALSO give me the entire rest of the deck to look it, it will be very hard for me to catch whether you are lying or not.
Even if you draw a dozen cards, I probably won't catch you lying.
It isn't until you are drawing a large fraction of the deck that you have to start thinking hard to make sure you don't contradict yourself.


Also: I apologies for not answering any of your original questions. I am not a climatologist, but all the things you suggested seemed plausible enough to me.



Andddddd... I have belaboured the point and used far too many words to say a simple thing.
Oh well.

[Mechalich]

if you're looking to build a high plausibility alternate Earth that you can model in detail you have too many changes set into your system. The initial post involves drastically changing land forms, ocean structure, continental position, elevation, and more. You have dozens of major changes that would all have major implications to the point that you're no longer building an alternate Earth history, you're crafting a new planet.

If you want to make an alternate earth as an exercise in world-building, try changing just one or two variables and working from there. For example, just moving Greenland to the north pole as you have done would create a land-based Arctic Ice cap and would drastically alter ocean processes and global temperature as a result.

[Eldan]

I agree with Mechalich there. THis is the kind of changes and level of detail where you're beyond "ask a geographer what would change" and more into "let's rent some expensive server time" territory.

[Lacuna Caster]

This is for a worldbuilding/alternate history textbook. And of course they matter because if the world isn't believable, then neither will the stories. No, I can't ignore three-quarters of the world because the global climatic system is interconnected.

Okay... so I think it is worth considering here that "Believable" and "Perfectly scientifically accurate" are very very different bars.
What I mean by that is that 99% of your audience are not climatologists. They do not know the first thing about how the climate works. If you make a story that is "Believable" to the 99% of the population who are not climatoligists, then you have done a pretty good job of believable.

If you then set you sights a little higher, and do some sensible LOCAL modelling (Oh look, a lake made central africa less desserty, because that IS how weather works") then you have probably made it convincing enough for 99.99% of the population.

Yeah, I'd have to agree with Nine Gardens here. I'm generally the last person to pooh-pooh good-faith efforts at scientific verisimilitude, but unless your specific player-group are all paid consultants for the IPCC, hand-waved explanations are probably good enough to allow for extensive suspension of disbelief.

[JohnDailey]

Okay, so when you say a worldbuilding/alternate history textbook, do you mean a textbook on HOW TO do alternate histories?
Or a textbook that exists inside and alternate history you are writing?


Okay... so I think it is worth considering here that "Believable" and "Perfectly scientifically accurate" are very very different bars.
What I mean by that is that 99% of your audience are not climetoligists. They do not know the first thing about how the climate works. If you make a story that is "Believable" to the 99% of the population who are not climatoligists, then you have done a pretty good job of believable.

If you then set you sights a little higher, and do some sensible LOCAL modelling (Oh look, a lake made central africa less desserty, because that IS how weather works") then you have probably made it convincing enough for 99.99% of the population.

If you have described a climactic system well enough that it would take a full scale global mathematical modelling in order to dispute your claim, then I think it counts as believable.

And more to the point:
Stories primarily lose believably not because of the science, but because of the characters.
Harry Potter loses significant believability not because there is magic in the story, but because Time turners are significantly underutilized by the main characters, who all know of their existence, yet don't make use of it nearly all the time. Or, perhaps more accurately, it loses believablity because a student is given a time machine in order to attended all her classes. The time machine itself we all accept.

You are right- the world does need to be believable, and in turn, the climate needs to be believable... but there are a million and one things that can break believably in a story, and as long as your climate is PLAUSIBLE you are good enough.

More to the point, if less Tornado Alley gives you the story you want, then just state "There are climate/geological details that make this work", and unless your story is REALLY centered in on the climate, people are willing to accept.



Well sure, you are right...
But unless your story is world spanning, you can just handwave and say "The rest of the worlds climate is such a shape as to make THIS part of the climate behave in the way my story needs it."

Unless your main character is a climatologist, it is unlikely that your stories are going to provide enough details that even a trained climate expert will be able to point to a contradiction.

It's like.... if you pick up a card from a deck of cards and say "This is the four of hearts"- unless you ALSO give me the entire rest of the deck to look it, it will be very hard for me to catch whether you are lying or not.
Even if you draw a dozen cards, I probably won't catch you lying.
It isn't until you are drawing a large fraction of the deck that you have to start thinking hard to make sure you don't contradict yourself.


Also: I apologies for not answering any of your original questions. I am not a climatologist, but all the things you suggested seemed plausible enough to me.



Andddddd... I have belaboured the point and used far too many words to say a simple thing.
Oh well.

To answer your first question, it's the latter. And adding to the point, I'm confining myself to the order of reality. World comes before history. History comes before story. Done in this order, you can create a believable world in which your stories will be believable, too. Done in a different order, even slightly, and you're just making stuff up as you come along, which shows poor planning. That's pretty much the common problem that modern fantasy suffers.

[Lacuna Caster]

To answer your first question, it's the latter. And adding to the point, I'm confining myself to the order of reality. World comes before history. History comes before story. Done in this order, you can create a believable world in which your stories will be believable, too. Done in a different order, even slightly, and you're just making stuff up as you come along, which shows poor planning. That's pretty much the common problem that modern fantasy suffers.

Okay, well, I went back and read your original post more thoroughly, and... well, it seems to me that some of your starting parameters presume that you can solve the climate question first? For example, if ocean currents or prevailing winds are disrupted by these changes to land-masses, would ice ages still occur in such a way as to scoop out some of the northern lakes?

I'm also curious as to what kind of inciting incident/s would have caused these changes in tectonic drift? Was there one or more significant meteor impacts (or a lack thereof, given your history seems to stretch back to the late-cretaceous), or do you just consider tectonic drift sufficiently non-deterministic that one could expect these divergences naturally? Do humans or something similar to them still exist?

I'm assuming you have some kind of expert background in geology, but I, uh... don't, so I'm not sure I can otherwise comment intelligently. Best of luck elsewhere, I guess?

[Goblin_Priest]

This is for a worldbuilding/alternate history textbook. And of course they matter because if the world isn't believable, then neither will the stories. No, I can't ignore three-quarters of the world because the global climatic system is interconnected.

The biggest issue in "believability" is, well, the changes themselves. Why? Why is there now a mountain range in the flattest part of North America? Why are water levels high enough to re-create the Champlain Sea (SuperSized version), but not to turn the amazon into a lake and sink Buenos Aieres?

The changes seem completely arbitrary to me. If you want an earth-like planet, with minor changes... there are plenty of models to use. "Earth without ice caps" looks fairly different due to increased water levels. Otherwise, go back in time. As close as the last ice ages, those had important effects on the landscapes. Or go back a few geological eras. Not only is the planet more believable, due to being based on RL models, but you'll probably be able to find actual documentation on how the planet was like. Because, to go back at your premise:

One of the most interesting to note was a planet that scientists call “Alternate Earth 111”, known to the public as “Great Lakes Earth”.

Why?

Because at first glance, it seemed that almost every continent is dominated by lakes, even those larger than the Great Lakes that we have in North America.

Of all the possible variations of Earth, I can't see why "having more lakes" would make this one "the most interesting to note".

But if you insist on going down this route, as others said, meteorologists represent a minority of the population. And I'm fairly confident that if you asked this to a meteorologist, he'd tell you it'd be pretty much impossible to predict. Meteorological systems are impossibly complex. They have a hard time guessing what tomorrow's weather will be like, don't expect them to predict massive planetary changes. Just handwave it all, I'd say.

[Flumphburger]

Lakes of those sizes forming in those places would require the entire geological history of earth from the Triassic onward.

Unless you're positing, like, alien geoformers who showed up at some point and just created a punch of lakes with supertech or whatever. In which case, we'd need to know when that happened.

[Blackhawk748]

Firstly, why is there a mountain range running through Nebraska? Just, what?

Secondly, those aren't lakes, those are freshwater seas and they are massive, like holy crap.

I have no real way of trying to explain what this would do to the weather other than...have fun predicting it. I live in the Midwest in between one of the Great Lakes and another large lake inland and weather prediction is an absolute nightmare around here, so I can only imagine what those will do.